Gorshkov A.M. "Pumps" State Energy --dat, 1947, 198 pages (5.25 MB. DJVU)
The guidance outlines the physical basis and principles of the calculation and the design features of piston, centrifugal, axial pumps, rotary, screw, mamut pumps, inkjets, erlifes, Taranians, etc. This manual can be recommended as an additional textbook for training students in educational institutions , energy directions.
The book discusses the main types of pumping equipment received widespread in the energy and industry. Do not even look at the year of publication (more than half a century), theoretical foundations and physical laws on which the work of the pumps remained the same and the design calculations are quite relevant today. Additionally, with questions outlined in the book, you can get acquainted with the Table of contents below.
Chapter first. Basic information 3
1. Purpose Pump 7
2. General classification of pumps 8
3. Brief historical information about pumps 8
4. The pressure developed by the pump 10
5. The efficiency of pumps 14
6. Types of engines to pumps 17
Chapter Second. Piston pumps 17
7. Principle of operation 18
8. Classification of piston pumps and typical schemes 19
9. Performance (feed) pumps 23
10. Air Caps 29
11. Suction and discharge processes 30
12. Indicator chart 43
13. Main details and accessories of piston pumps 48
14. The designs of piston pumps and their industrial use 56
15. Source positions when choosing a piston pump 66
16. Changing the pump operation mode (regulation) 67
17. Rules for starting, stopping and caring for pump 69
CHAPTER THREE. Centrifugal pumps 70
18. Principle of operation 71
19. Classification of centrifugal pumps 72
20. The ideal flow of fluid in the handling wheel 74
21. Basic Centrifugal Pump Equation 76
22. Device for energy conversion in pumps 82
23. Theoretical characteristics of the centrifugal pump 85
24. Actual characteristics of the centrifugal pump 88
25. Universal pump characteristic. Proportionality laws 94.
26. Speed \u200b\u200bratio 97
27. Suction height. Cavitation 99.
28. Axial pressure and ways to unload 105
29. Basic parts of centrifugal pumps 107
30. Constructions of centrifugal pumps and their industrial use 110
31. Determining the operating mode of the pumping unit 127
32. Parallel and consistent operation of pumps 132
33. Regulation of centrifugal pumps 136
34. Stroke, stop and care for centrifugal pumps 137
Chapter fourth. Propeller (axial) pumps 138
35. Principle of operation 139
36. Basics of wing theory 141
37. Determination of the pressure and supply of the pump 145
38. Characteristics of propeller pumps. Regulation 148.
39. Constructions of propeller pumps and their industrial use 151
40. Choosing a pump type 157
Chapter Fifth. Pumps used in power engineering 158
41. Pumping equipment of thermal stations 159
42. Pumping equipment peatwork 165
Chapter Six. Other types of pumps 167
43. Foreign pumps 173
44. Rotary pumps 174
45. Screw pumps 177
46. \u200b\u200bInkjet pumps 177
47. Erlifed 179.
48. Hydraulic Taran 181
49. Assembly 183.
50. Pulse meter 183.
51. Gamphrey pumps 184
Subject indicator 187.
Tutorial
Start in the operation of the nutritional electric pump after repair
Gruzdev VB
The method of preparation and start of the nutritional pumping unit with an electrical drive is considered. In detail describes the sequence of technological operations during the launch of the nutritional pump and its oil system. A brief description of the operation of centrifugal pumps on the network is given. The appendix shows the illustrations explaining the operation of the nutritional pump. Emergency situations are also given and their successful solution. Compiled lists of control questions to each chapter.
It is intended for students in part - correspondence training in training in the specialty 140100 "Heat and Power Engineering". It can be useful to students of other specialties, when studying the discipline "Modes of operation and operation of the TPP", as well as all engineering and technical workers and working thermal and nuclear power plants.
electric oil pump centrifugal pump
Introduction
Chapter 1. Main parameters and classification of pumps
3.3 Possible causes of emergency disconnection of a working oil pump
3.7 Control questions
4.4 Control questions
5.5 Control questions
Applications
Literature
Introduction
The purpose of this study manual is to study with students with the general scheme of the strapping by pipelines and auxiliary equipment of the nutritional electric pump and its oil supply system, as well as their start-up work after repair.
When describing the nutritional electric pump and start to work after repair with options for emergencies, both the most nutrient pump and its auxiliary systems, used well-known technical literature on pumps and more than 20 years of experience of the author of the author of the Zaina GRES (Tatarstan) , Leningrad and Chernobyl NPP, which made it possible to summarize and create a real allowance, and thereby develop a methodology for preparing for a start-up and launch of nutritional electric pumps to work after the repair of power units of thermal and nuclear power plants.
During the study, students will receive the skills to solve operational tasks when starting the operation of the power pumps with an electrical drive. The launch of the nourishing pump with a turbid, where the steam turbine is used instead of the drive electric motor, is not significantly different with the exception of start-up operations on the drive turbine. In the next manual, we will consider such a launch of the nutritional pump, the more turbines are equipped with a large fleet of nutrient pumps of Russian and foreign power units with a capacity of 300 and more MW.
Now we remember that the pumps are called hydraulic vane machines intended for lifting and supplying liquids, in our case - feed water from DeaErator.
Chapter 1. Basic parameters and classification of pumps
The terms in the pump area are installed GOST 17398-72 "Pumps. Terms and Definitions". According to this, GOST pumps are divided into two main groups: dynamic and volumetric.
Dynamic is called pumps in which the fluid under the influence of hydrodynamic forces is moved in the chamber (open volume), which is constantly communicating with the input and output of the pump.
Volumenny is called pumps in which the fluid moves by periodic changes in the volume of the liquid chamber, alternately communicating with the entrance and output of the pump.
Dynamic pumps are divided into padded, friction and inertial pumps.
Blades are called pumps in which the fluid moves due to the energy transmitted to it when the impact blades of the impeller. Bladed pumps combine two main groups of pumps: centrifugal and axial. In centrifugal pumps, the fluid moves through the impeller from the center to the periphery, and in the axial, through the impeller in the direction of its axis. Often pumps are supplied in the form of a pumping unit, the pump and the engine connected to it. As an engine can be both electrical and steam machines.
In addition, there is a concept for a pumping unit, i.e. the pump unit with a set of equipment mounted according to a specific scheme that ensures the operation of the pump in the specified conditions.
In addition to terms relating to constructive and other signs of pumps, GOST 17398-72 establishes the terminology of the basic technical indicators of pumps and pumping units.
The main of these indicators is the volume supply of the pump - the volume of the fluid supplied by the pump per unit of time. Water supply is measured in m 3 / s or m 3 / h. It is allowed to measure the flow in L / s.
There is a concept mass feed - the mass of the supplied fluid per unit of time. Mass feed is measured in kg / s (T / s) or kg / h (t / h) and is defined as the second main indicator of the pump is the pressure-developed pressure or pressure and is determined by the increase in the specific energy of the water when its flow from the entrance to the pump output . The pressure is most often measured in a water column meters (water m. Art.) Or in the atmospheres (atm).
To determine the value of the total pressure of the pump n, the following formulas are used:
H \u003d p 2 / ρg - p 1 / ρg + ΔH + (V 2 2 - V 2 1) / 2G, (water. V. Art.) (1)
H \u003d HM + (V 2 2 - V 2 1) / 2G, (water. Art.), (2)
where P 2, p 1 is the water pressure, respectively, in the pressure and suction pipes of the pump, ATM;
ΔH \u003d (z 2 - z 1) -
the distance vertically between the point of installation of the pressure gauge on the pressure and the vacuum meter on suction, m;
v 2, V 1 - water velocity in the injection and suction pump nozzles, m / s;
ρ is the density of water, kg / m 3.
HM is a pump manometric pressure, which is the sum of the testimony of the pressure gauge on the pressure of the pump, the vacuum meter on the USHE, and the geometric pressure between the points of installation of these devices ΔH.
The pump pressure can also be expressed in the form of water pressure at the outlet of it:
P \u003d nρg, (m. Vod.st.) (3)
The pressure is measured in KPA, MPa, ATM or KGS / cm 2, and the pressure is in the meters of the pumped fluid. For example, a water column meter is recorded as - waters. Art., and 10 m. Waters. Art. \u003d 1.0 atm. \u003d 1.0 kgf / cm 2 \u003d 0.1 MPa. The volume supply Q of the pump is measured in m 3 / s, and the mass feed M - in kg / s, which is defined as
where ρ is the density of the medium, kg / m 3.
In turn, the bulk feed is almost the same along the entire length of the flow part of the pumps and can be calculated on the average velocity of the medium using the stream equation:
where f is the cross-sectional area of \u200b\u200bthe fluid flow, m 2;
C is the speed of the medium, m / s.
The amount of energy spent per unit time per pump drive determines its useful power:
NP \u003d ρG QH, (kW) (6)
Np \u003d ρqh / 102, (kW) (7)
where q is the pump performance, m 3 / s;
ρ is the density of the medium, kg / m 3;
N - full pressure pump, m. Vod.st.
Energy loss are inevitable in any working process and the actual power spent on the pump drive, more theoretical value:
N \u003d np + Δn, (8)
where Δn is the Cum of all energy losses arising due to the imperfection of the pump as a paddle machine.
To estimate the completeness of the use of energy that is supplied to the pump from the engine, use the characteristic called an effective efficiency of the aggregate:
Thus, knowing the efficiency, the pressure and pump feed can be calculated by finding the power consumption of the pump:
N \u003d ρgqh / η \u003d np / η, (kW) (10)
But the dimensionless value is very important for bladed machines, which is called the speed gain.
The ratio ratio NS is used to compare the geometric parameters and technical and economic indicators similar to the pumps with different values \u200b\u200bof the pressure, flow rate and number of revolutions. Why do you need it? The NS coefficient allows, when designing and operating one pump to replace others, which is especially important at present. Physically, the coefficient of high speed is understood as the frequency of rotation of the virtual model pump, geometrically similar in all elements of natural, with the same hydraulic and volumetric coefficients of efficiency, provided that the model pump creates a pressure equal to 1 meter of water column, with hydraulic power in 1 hp. ., i.e. The flow of the model pump is q \u003d 0.075 m 3 / s on the maximum perm., if we assume that the water density is 1000 kg / m 3 under normal physical conditions.
It is known that the coefficient of speed is the function of three arguments - the performance of q, the pressure of H and the number of revolutions N rotor of the pump, i.e. NS \u003d F (Q, H, N), and estimates the optimal mode of operation of the blade machine. With it, it is also convenient to classify the type of pump type of the working body, to evaluate the choice of the number of compression steps, summarize the technical and economic indicators of various types of pumps. The formula for calculating the NS is removed by natural modeling of processes in blade machines, i.e. empirically, and is written in the following form for pumps supplying water with a density ρ \u003d 10 3 kg / m 3
nS \u003d 3.65 N√Q / H 3/4, (11)
where n is the number of revolutions of the pump, rpm;
Q - supply (performance) of the pump, m 3 / hour;
H - pressure pump, waters. Art. (For multistage pumps with identical working wheels, the head coming on one wheel).
Thus, the rapidity ratio allows you to combine various wheels of pumps into the group on the basis of their geometric similarity and is a purely calculated parameter, with which it is convenient to classify the type of pump on the working bodies, evaluate the choice of the number of steps for a multi-stage pump, to summarize the technical and economic indicators of various pumps.
Usually apply the following classification of the working wheels of centrifugal pumps in terms of speed ratio:
one). Pacific, n s \u003d 50-100;
2). normal, n s \u003d 100-200;
3). speed, n s \u003d 200-350
Let us give an example of the practical application of the speed gain. For example, we need to determine the number of steps of the selected nutrient pump with a flow rate Q \u003d 650 m 3 / hour, pressure of 2000 waters. Art. (200 atm), the number of revolutions N \u003d 2850 rpm (drive from an asynchronous electric motor).
First, define the NS speed coefficient according to formula (11), which will be equal to 663.
nS \u003d 3.65 N√Q / H 3/4.
Then ns \u003d 3.65 x 2850 x √ 650/2000 3/4 \u003d 663,16 ≈ 663.
Now we determine the head of one stage of the N1 pump by the formula:
H1 \u003d (3.65N √Q / NS) 3/4
H1 \u003d (3.65N √Q / NS) ¾ \u003d (3.65 x 2850 x √650 / 663) ¾ \u003d 400 m. Waters. Art.
Sharing the required complete pressure of 2000 waters. Art. On the head of one stage, we obtain the number of steps of the selected nutrient pump - 2000/400 \u003d 5 steps in the pump that satisfy the specified hydraulic requirements.
The selection of the pump is usually carried out for the specified operating conditions of the external network at the required supply, pressure, temperature, as well as the physico-chemical properties of the pumped liquid (corrosion properties, viscosity and density of the liquid). The feed and pressure of the pump must correspond to the characteristic of the hydraulic resistance of the external network, which consists of a system of pipelines and reinforcement. In this case, the pump must provide the maximum possible submission for this network. But given the possible deviations of the characteristics of the selected pump in the manufacture of it at the factory, it is still chosen by 3-5% higher than the desired pressure to overcome the hydraulic resistance of the network. Much important and correct installation of the pump. Pumps sometimes establish that the level of the suction nozzle is above the liquid horizon in the receiving tank or in the chamber.
In such cases, a vacuum (vacuum) is needed in the pump inlet nozzle, due to which the liquid will be absorbed into the pump under the action of the pressure of the atmospheric air column. The height of suction developed by the blade pump is defined as:
HBS \u003d (P 0 - P 1) / ρg, (12)
where P 0 is atmospheric pressure or pressure in the container to which the pump, ATM is connected; ρ is the density of fluid, kg / m 3; G - Acceleration of free fall, equal to 9.81 m / s 2
In the pump catalogs, the allowable vacuum height of the NVS suction is always indicated, i.e. The height at which the operation of this pump is ensured without changing its basic technical indicators. It is known that the reliability and stability of the operation of energy pumps depends on the value of the permissible height of suction. Therefore, it briefly remember that such a height of suction of pumps and especially cavitation phenomenon. The fluid on the suction pipe to the pump's impeller is supplied under the action of the pressure difference in the receiving tank and the absolute pressure in the stream at the entrance to the wheel. The latter depends on the location of the pump relative to the level of the liquid surface in the tank and the pump operation mode. In practice there are three main schemes for the installation of centrifugal pumps:
Fig. 1. Installation schemes of centrifugal pumps
1. The pump axis is higher than the water level (0-0) in the receiving tank (chamber) - (Fig. 1, a);
2. The pump axis below the water level (0-0) in the receiving tank (Fig. 1, b), i.e. The pump is under the guaranteed water bay;
3. The pump axis is below the water level (0-0) in the receiving tank and it is under excess pressure (Fig. 1, c), so the pump is under the guaranteed water bay. As follows from Fig.1. The best ways to connect the pump to the water source are options b) and B), because There is a very high guarantee that the pump will not be thrown in work, i.e. In Usavy, there will always be a sub-project of water while its redundant level at the entrance to the pump is present, and the most inconvenient method is an option a). Here, water must be driven into the pump, and for this you need to create a vacuum in the pump inlet and put the check valve on the suction pipeline, always fill with water of the suction pipeline, while the check valve must keep this water and not release from the pump. When the pump is turned on, it itself will create a vacation and water on the pump under the action of atmospheric air pressure. When the pump is disconnected, the check valve must not miss the water from the pump and keep it in the pump cavity, otherwise it will have to fill it again or repair the check valve. As you can see this uncomfortable way to connect the pump, but it is used when you need to pump water from the well, an underground tank or a pit. In any case, all these methods are widely used both in power plants and other industrial enterprises and in everyday life.
From the Bernoulli equation for two sections (in our case, for the water level in the receiving tank 0 - 0 and the cross section at the entrance to the pump (Fig. 1.)) follows:
HG.V. + H P.V. \u003d PA / ρG - PN / ρG- V 2 V / 2G, (13)
where h p.v. - loss in the suction pipe, Pa;
ra - atmospheric pressure, PA;
rV is an absolute pressure at the entrance to the pump, Pa;
vV - water velocity at the entrance to the pump, m / s.
The left part of equation (13) is a vacuum height of the pump suction and is measured in a water column meters of the pumped fluid.
You can also write down that the height of the suction of the pump HB
HB \u003d H G.V. + H P.V. (fourteen)
From the analysis of formulas (13, 14) it follows that if the water in the pump comes with the sub-line (Fig. 1, b),
HB \u003d H P.V. - H G.V. (fifteen)
The negative value of H B indicates the operation of the pump with the backup.
When the pump is running according to the diagram shown in Fig. (1, c), the expression of the vacuum height of suction acquires the form:
HB \u003d / ρg, (16)
where P 0 is the absolute pressure of the medium over the free surface of the liquid, Pa.
Depending on the design of the vane pump, the geometric height of suction is counted differently.
For horizontal pumps H G.V. - This is the difference between the pump axis and fluid level in the receiving tank.
For pumps with vertical shaft N G.V. It is counted from the middle of the input edges of the blades of the impeller (in the multistage pumps of the wheel of the first stage) to the free surface of the fluid in the receiving tank.
It must be remembered that the normal operation of the centrifugal pump is provided only in this mode when the absolute pressure at all points of its inner cavity is greater than the pressure of the saturated vapor of the pumped fluid at a given temperature.
If such a condition is not respected, the phenomena of vaporization and cavitation begins, which lead to a decrease or even stopping the pump feed (the pump "breaks") and fail.
Cavitation - from the Latin language (Cavitas) means - emptiness. So what is this phenomenon under such a beautiful and sonorous name?
Cavitation is the process of a continuity disorders inside the fluid flow, i.e. Education in drip liquid cavities filled with gas, steam or their mixture (cavitation bubbles or "cavity", i.e. emptiness). Usually cavitation flows are characterized by a dimensionless parameter (cavitation number):
, (17)
P - hydrostatic pressure of the incident flow, Pa;
P S - the pressure of saturated vapor of liquid at a certain ambient temperature, Pa;
ρ - medium determination, kg / m³;
V is the flow rate at the entrance to the system, m / s.
It is known that cavitation occurs when the boundary speed flow V \u003d V C is reached when the pressure in the stream becomes equal to the vaporization pressure (saturated vapor). This velocity corresponds to the boundary value of the Cavitation criterion.
Depending on the magnitude of χ, you can distinguish between four types of threads:
· Provitalization - solid (single-phase) flow at χ\u003e 1;
· Cavitational - (two-phase) flow at χ ~ 1;
· Film - with a stable separation of cavitation cavity from the rest of the solid stream (film cavitation) at χ< 1;
· Supercautional - with χ<<1.
The required cavitation reserve ΔH TP is usually calculated according to the characteristic submitted by the pump manufacturer. The ΔH TP curve begins with a zero feed point and slowly grows with magnification. When the feed exceeds the point of maximum pump efficiency, the ΔH TP curve increases sharply by exponential. The zone to the right of the maximum efficiency point is usually cavitational dangerous.
The cavitation supply is not amenable to control from the point of view of mechanics and the pumping station driver only hears it as metal noise and clicks, but this is already developed cavitation.
Unfortunately, there are still few devices to observe and prevent cavitation. Although the pressure sensor on the suction side of the pump that feeds the alarm when the pressure drops below is permissible for this pump must be applied everywhere.
According to the experience of exploitation of pumps, it is known that the sounds of crackling disappear after covering the pressure gate. But, thereby reducing the flow and cavitation, you can not reach the technological parameters of the pump itself.
In order to correctly eliminate cavitation be sure to use the basic principle - at the entrance to the pump should always be liquid more than at the output.
I will give a few simple ways to achieve this:
1. Replace the diameter of the suction nozzle on a larger size. It must be remembered that the diameter of the pump of the pump should always be larger than the diameter of the pressure;
2. Purge the pump closer to the water source or to the nourishing tank, but not closer to the 5-10 diameters of the suction pipe;
3. Implement resistance in the suction pipe, replacing its material on less rough;
4. Replace the suction valve on the girlfriend characterized by smaller local losses;
5.If suction pipe has turns, then reduce their quantity or replace the tans of small on large rotation radii, orienting them in the same plane (sometimes replacing the rigid flexible tube);
6. Increase the pressure on the suction side of the pump with an increase in the level in the feed tank or a decrease in the pump setting axis, or install the booster pump.
It is well known that cavitation arises as a result of a local pressure reduction below the critical value and for a real liquid it is approximately equal to the pressure of a saturated pair of this fluid at a given temperature. As a result, the formation of a large number of smallest bubbles filled with vapors of liquid and gases released from it. The formation of bubbles is externally similar to boiling liquid.
The bubbles arising from reduction of pressure increase in size and are carried out by a stream.
In this case, there is a local increase in the speed of the fluid movement due to the constraint of the flow cross section with allocated steam or gas bubbles.
Finding into the area with a pressure above critical, bubbles are destroyed, with their destruction occurs at high speed and therefore is accompanied by a local hydraulic blow in this microscopic zone. Since condensation occupies some region and proceeds continuously for a long time, this phenomenon leads to the destruction of significant areas of the surface of the working wheels or the guide machines of the pump.
Almost the appearance of cavitation during the operation of the pump can be detected by characteristic crackling in the suction area, increasing noise and the sudden appearance of increased vibration of the pump. Cavitation is also accompanied by chemical destruction (corrosion) of the pump material under the action of oxygen and other gases that have been separated from the liquid in the area of \u200b\u200breduced pressure.
With a simultaneous action of corrosion and cyclic mechanical effects, the strength of metal parts of the pump is rapidly decreasing. In this case, the effects of cavitation on the metal parts of the pump is enhanced if the pumped liquid contains weighted abrasive substances: sand, fine particles of slag, etc.
Under the action of cavitation, the surface of the parts becomes rough, spongy, which contributes to the rapid abrasion of suspended substances. In turn, these substances, abrade the surface of the pump parts, contribute to strengthening cavitation.
Cavitational destruction is most susceptible to cast iron and carbon steel, and the least - bronze and stainless steel.
Fig. 2. The destruction of the impeller of the centrifugal pump under the influence of cavitation
In order to increase the stability of parts of the pumps from destruction, protective coatings are used. For this surface, the parts are removed with solid linings from solid alloys (stellites), use local surface hardening and other ways to protect. However, the basic measure of the premature wear of the flow part of the pumps is the prevention of cavitation modes of their work.
In technical documentation for pumps (catalogs, passports, etc.), the permissible height of the suction (or permissible cavitation reserve) must be indicated for normal physical conditions, i.e., for atmospheric pressure 0.1 MPa (which corresponds to 760 mm Hg. Art. ) and the temperature of the pumped liquid 20 ° C.
Consequently, the main technical characteristics that determine the operation of any pump are:
1. pressure (NN, waters. Art; atm.; Kgf / cm 2; pa, kpa, MPa);
2. Feed (Q, l / s; m 3 / hour; kg / s; t / h);
3. Power consumption (N, kW);
4. Efficiency coefficient (η,%);
5. Rotation frequency (N, rpm);
6. Height of the pump suction (N of Sun, m. Water. Art.).
From the specified pump parameters, the feed and frequency of rotation are independent variables, and the remaining parameters are in functional dependence on the supply and frequency of its rotation. The relationship of parameters in various pump modes is usually depicted graphically as characteristics.
To obtain them, it is necessary to conduct the tests of the pump in various conditions of suction, with various heads, feeds and capacities varying from the minimum to maximum values. Only as a result of these tests can be obtained an idea of \u200b\u200bthe operation of the pump and its energy indicators.
The experimental characteristics of the pump are the necessary technical material to assess the quality of the pump, to select the mode of its operation and for the implementation of proper and reliable operation. These experienced characteristics are obtained on the tests of each pump at the factory and are attached to the technical documentation when selling a pump.
We will not consider the construction of the normal and other characteristics of the pumps, as well as the use of a mathematical apparatus for calculating pumps, because it is not included in the task of our manual, so we address the inquisitive reader to the literature, which is given at the end of the manual.
By the nature of the physical and workflow in the pump, the mechanical energy of the drive motor into the hydraulic energy of the fluid moved is occur.
We already know that there are dozens of different types of pumps, but of them the main and frequently used in power plants are volumetric and blade. In bulk pumps, energy transmission is carried out by compulsory exposure to the working body (plunger, piston, rotor) on the transported medium and its displacement (plunger, piston, rotary pumps). In the blade pumps, the transformation of mechanical energy into hydraulic is produced by an implacable rotor with a rotor with a rotor, equipped with blades (centrifugal, axial, vortex, diagonal pumps). At modern power plants, both in Russia and abroad are mainly used by the CBN - centrifugal pumps and it is axial pumps. Check valve on the pump:
Fig. 3. Scheme of the pump unit of the centrifugal type
1 - open source of water;
2 - suction piping;
3 - open injected tank;
4 - flowing insert in the pressure pipe;
5 - Centrifugal pump;
6 - electric motor;
M - pressure gauge on the pump pressure;
V - Manovakuumetre on the pump suction;
P - atmospheric pressure.
In fig. 4 shows a section and device of a conventional centrifugal single-stage pump.
Fig. 4. Centrifugal pump diagram
1 - expanding pump housing ("snail");
2 - pump shaft;
3 - impeller;
4 - blades of the impeller;
5 - Supporting (suction) pump nozzle;
6 - reducing (pressure) pump nozzle.
Inside the pump of the pump 1, having, as a rule, a spiral shape in the form of a snail, on the shaft 2 impeded impeller 3. The impeller consists of the rear and front discs, between which the blades are installed 4, bent from the radial direction to the side, opposite the direction of rotation of the worker wheels.
Using pipes 5 and 6, the pump housing is connected to suction and pressure pipelines. If, with a liquid-filled housing and a suction pipeline, lead the impeller to rotate, the fluid located in the channels of the impeller (between its blades), under the action of centrifugal force will be discarded from the center of the wheel to the periphery. As a result, a vacuum is created in the central part of the wheel, and on the periphery - overpressure. Under the action of this pressure, the liquid from the pump enters the pressure pipeline, simultaneously through the suction piping under the action of the vacuum, the liquid enters the pump. Thus, continuous fluid supply is carried out by a centrifugal pump.
Centrifugal pumps can not only be single-stage (with one impeller), as shown in Fig. 2, but also multistage (with multiple working wheels). In this case, the principle of their action in all cases remains the same - the liquid moves under the action of a centrifugal force developed by the rotating impeller.
The so-called diagonal pumps were distributed abroad, the design of which combines signs of centrifugal and axial pumps. In contrast to centrifugal in diagonal pumps, the flow comes out of the wheel at an angle not 90 °, but at 45 °.
In the diagonal pumps, the fluid flow passing through the impeller is not aimed radially as in centrifugal pumps, and not parallel to the axis, as in axial, but obliquely, as if on the diagonal of the rectangle composed of radial and axial directions.
The inclined direction of the flow creates the main constructive feature of the diagonal pumps - the location of the impact of the impeller to the axis of the pump. This circumstance allows you to use the joint action of the lifting and centrifugal forces when creating a pressure and, according to its working parameters, diagonal pumps occupy an intermediate position between centrifugal and axial pumps.
Like CBN and axial, diagonal pumps are manufactured both in horizontal and with a vertically located shaft.
Fig. 5. Diagonal pump cut with horizontal rotor
Fig. 6. axial type pump
1 - pump housing; 2 - guide fixed vehicle pump; 3 - rotating rotor of the pump; 4 - rotating around their own axis working blades of the pump rotor.
Fig. 7. Inkjet Pump
1 - confusion on the supply of the motivating medium (water, gas);
2 - nozzle exhaust liquid (gas);
3 - a mixing chamber of the mixing and suused medium (vacuum chamber);
4 - diffuser part of the injection pressure of the pump.
Fig. 8. Togoto pump
1 - pump housing;
2 - suction part of the pump;
3 - Safety-bypass valve;
4 - pressure part of the pump.
Fig. 9. Piston pump (plunger)
1 - pump housing;
2 - piston (plunger);
3 - cylinder;
4 - piston rod;
5 - crank;
6 - rod;
7 - drive;
KV - Valve on ASHE into the pump;
KN - Valve injection from the head of the pump
The Hydraulic Pumps of Centrifugal Action, which have a very high rise in pressure, especially multi-stage execution, are used on the TPP. Mechanical energy is supplied in the form of a rotating moment and a liquid is transmitted through the blades of the rotating impeller. The effect of the blades on the liquid fill in the impeller causes an increase in the hydrodynamic pressure and causes the fluid to move in the direction from the center of the impeller to the periphery, throwing it into a spiral casing. In further movement, the fluid enters the pressure pipeline. It follows that the main working body of the centrifugal pump is freely rotating inside the housing of the blade wheel. In fig. 10, 11 shows photos of the impeller of the centrifugal pump. In turn, the impeller consists of two vertical disks (front and rear fluid flow), as shown in Fig. 10, sitting at some distance from each other. Between the discs, connecting them into a single design, there are blades, smoothly curved to the side, opposite to the direction of rotation of the wheel (Fig. 9), i.e. Fluid flow. The inner surfaces of the discs and surfaces of the blades form interbalance channels of the wheels, which when the pump is filled with pumped liquid.
Fig.10. Working wheel of the centrifugal pump in the context
Fig. 11. Working wheel of the centrifugal pump assembly
From the course of theoretical mechanics, it is known that when the wheel rotates with an angular velocity ω (1 / s) on the elementary mass of the M (kg) fluid, which is in the inter-stable channel at a distance of R (m) from the shaft axis, the centrifugal force F C.B . defined by the expression:
F C.B \u003d M Ω 2 R (18)
In engineering calculations, formula (19) is also applied equivalent to formula (18):
F C.B \u003d MV 2 / R, (19)
where V (m / s) is a linear velocity of the elementary mass of the substance on the R radius from the center of rotation.
We have already said that in order to ensure the continuous movement of fluid through the pump, it is necessary to ensure its permanent supply to the pump and the pump from the pump. Therefore, the fluid comes through the hole in the front disk of the impeller on the suction pipe from the suction pipeline.
For example, the movement of water on the suction pipe into the nutritional pump is due to overpressure in the deaerator housing and the feed water column, equal to the difference in setting the installation of the DeaErator's battery tank and the installation of the nutrient pump in the engine room of the main power plant building.
The usual setting of the battery pack of the block deaerator is 20 ÷ 24 meters in the location of the deaerators of the power plant, depending on the power of the power unit, and the installation of the nutritional pump is performed at a mark of 0.0 ÷ 5.0 meters in the Masseal of the main power plant building. It follows that the difference in setting the installation of the accumulatory tank of the deaerator and the nutrient pump can be 15.0 - 19.0 (24 - 5 \u003d 19) meters and if we take the temperature and specific volume of nutrient water in the battery tank, as well as the hydraulic resistance of the hydrate piping pipeline Water to the NSAs of the Nutrient Pump, it turns out that the suboro on the suction of the nutrient pump will be 13 ÷ 17 m. Waters. Art. or 1,3 -1.7 atm. This makes it possible to partially relocate from the dangerous phenomenon of cavitation, having a guaranteed supply by the pressure of the nutrient water on the suction of the nutritional pump. In fig. 12 shows the hydrostatic diagram of the nutritional pump as an illustration of the above.
Fig. 12. Hydrostatic Nourishing Pump Scheme
A - setting the installation of the Deaerator battery tank;
B - Marking of the nutritional pump;
H1- The height of the level of the nutrient oily in the deaerator battery tank;
H2 is the difference between the installation of the deaerator battery tank and the nutritional pump.
Analysis of equations (18.19) shows that the centrifugal force, therefore, the pressure developed by the pump, the greater the greater the speed of rotation of the impeller.
But an increase in the rotational speed of the pump rotor is limited by the frequency of rotation of the electric motor, because Any high-speed electric motor is mainly used as a centrifugal pump drive, but most often an asynchronous type electric motors are used for this purpose, the speed of which is slightly below the synchronous speed.
The use of other electric motors, as well as electrical devices for adjusting the number of rotation of the electric motor, although they allow you to change the rotational speed of the pump rotor, but they did not get widespread on power plants as a feed pump drive due to its complexity and not reliability.
In this regard, recently, the electric and foreign power plants has been widely used by the power pump with hydromefta, which is provided in the application, fig. P-1.2.
Depending on the required parameters, assignments and working conditions, a large number of various designations of centrifugal pumps have been developed, which can be classified by several features. For example, according to the number of working wheels, single-stage and multistage pumps are distinguished. In multistage pumps, the pumped fluid passes sequentially through a number of operating wheels planted on the overall shaft.
The pressure created by such a pump is equal to the sum of the heads developed by each wheel.
Depending on the number of wheels (steps), the pumps can be two-stage, three-stage, etc. In essence, several single-stage pumps are located on the same shaft, which consistently increase the pressure of the entire pump, which is its main pressure-consumable characteristic.
According to the method of flowing water to the impeller, the pumps with one-sided and pumps with double-sided submarine or, so-called centrifugal pumps of the two-way water inlet are distinguished.
According to the method of removal of fluid from the impeller, the pumps are distinguished with a spiral and turbine tap.
In the pumps with a spiral tap, the pumped liquid from the impeller comes directly into the spiral chamber and then either fall into the pressure pipeline, or on the overlete channels goes to the following impellers.
In pumps with a turbine removal, the liquid before entering the spiral chamber passes through the system of fixed blades forming a special device, called the guide apparatus installed in the stator of the pump.
According to the layout of the pump unit (the location of the shaft relative to the supports) distinguish the pumps of horizontal and vertical execution.
By the method of compounding with the engine, centrifugal pumps are divided into drive (with a pulley or gearbox) connected directly to the engines with the coupling, and the monoblock, the impeller of which is installed at the elongated end of the motor shaft - console pumps.
For example, the cantilever pumps are designated as K-120-15, i.e. Console pump, with a capacity of 120 m 3 / hour and pressure of 15 atm.
The pressure of single-stage centrifugal pumps, serially produced by the Russian industry, reaches 120 m. Waters. Art. (1.2 MPa; 12 atm).
In turn, serial multistage pumps develop pressure up to 2500 m. Waters. Art. (25 MPa; 250 atm) and more.
The parameters of the centrifugal pumps of special manufacture, both single-stage and multistage, can be significantly higher.
As for the efficiency, depending on the constructive design, it changes widely - from 0.85 to 0.90 in large single-stage pumps and 0.55-0.60 in high-pressure multistage.
So low kpd. Multistage high-pressure pumps are associated with hydraulic losses in the flow of the pump and especially with high friction of the discharge steel disk of the hydraulic spot in the pump unloading system.
In turn, the friction of this monolithic cast-iron disk with a thickness of 30-40 mm and a diameter of about 300 mm at a rotational speed of almost 50 rd / s in a closed water volume (in the chamber hydrophits) leads to a noticeable heating of water in the pump, the temperature of which is taken into account in the heat cycle of Renkina .
It is also known that the power consumption of the pump at zero feed, i.e. With a closed output valve (this is idle pump), does not drop to zero and is about 30-40% of the rated power of the electric motor. This power also turns into the heat of heat, which is capable of increasing the temperature of the nutrient water to the effect of the "bearing" of the pump, in which the mechanical exposure is undergoing working wheels, an unloading device, support bearings, a pump shaft seal and ultimately can lead to emergency pump output from work . Increasing the temperature of nutrient water ΔT in without consumable mode is determined by the formula:
ΔT \u003d 632n (1-H) / 1000Q (o C), (20)
N - power of the electric motor, kW;
h - kpd. pump;
Q - pump feed, kg / s.
From equation (20) it follows that with a decrease in the supply of the pump q, the temperature of the nutrient water increases.
Sometimes, the machinists are used in increasing the temperature of nutrient water during the start of power units, which, of course, is not economical and not rationally from the point of view of the reliability of the pump unit. From, p. 68, it follows that the maximum allowable increase in water temperature reaches 11 o C and is based on the assumption that only the heat due to hydraulic losses inside the pump contributes to the increase in the temperature of the nutrient water in the pump for this value. In fact, the limit of increasing the temperature of the water in the pump is most often arbitrary. For example, for pumps that do not have unloading devices (recycling line), sometimes to maintain minimal consumption through a fitted pressure valve, an increase in temperature is allowed to 30 ° C to avoid its "bearing".
But in any case, the operation of the centrifugal pump, especially multi-stage, in Russia is not allowed more than three minutes.
In modern major power plants, the power of the electric motors of the feed pump reaches several thousand kilowatts. From here you can imagine how quickly the temperature of the nutrient water can rise at zero consumption, when these thousands of kilowatt of electrical energy will be converted to thermal energy.
But no matter how there was no centrifugal pumps differ from other pumps with a unique property of self-regulation and the possibility of forced regulation in a wide range of their performance and pressure. Under self-regulation is understood to be an independent change in the mode of operation with a change in the resistance of the network, which is especially important for the power pumps with the electric drive and the maneuverability of the power units. This CBN property is widely used during the operation of pumps, especially when they are turned on in parallel operation to a general hydraulic network, both with planned inclusion and an emergency automatic reserve (AVR). In the following section, we will look at the options for incorporating the nutritional pumping in the power plant scheme.
Chapter 2. Nutritional installations of thermal power plants
2.1 Turning on the nutritional pump to the thermal circuit of the power plant
We know that the nutritional pump is pumping the nutrient water from the deaerator, increasing its pressure to P.N. . \u003d (1.25-1.3) p 0, where p 0 is the pressure of acute steam before the turbine, taking into account the resistance of the nutrient path and the surfaces of the heating of the steam boiler. In modern power plants, several inclusion of nutrient pumps are used, but we will consider only two of them most applied.
1. A single diagram in which the nutritional pump supplies water with a finite calculated pressure through the PVD to the nutritional node of the steam boiler:
Fig. 13. The fundamental single-lifted circuit in the inclusion of the nutritional pump
This scheme is applied on power units with a capacity of up to 200 MW.
The advantages of this scheme:
1. Relative simplicity adjusting nutrient water consumption by a nutrient pump.
Feature: High pressure heaters (PVD) work under a very high pressure generated by a nutritional pump. Because of the high pressure drop in PVD, high demands for reliability of work and increased capital costs for its provision associated with an increase in the thickness of the wall of the heat exchanger hull is placed.
2. A two-lifted circuit in which the nutrient pumps of the first lift pump water through the PVD to the nutritional pumps of the second lift feeding in the steam boiler:
Fig. 14. A fundamental two-way power supply circuit of the nutritional pump
This scheme can be used on 300 MW power units and above.
The advantages of this scheme:
1. Performing PVD for less pressure, determined by the fact that the pressure of water at the entrance to the second lift pumps should be somewhat higher than the saturation pressure at the water temperature in front of the pumps, so the requirements for reliability of PVD are somewhat less than in single-models.
Disadvantages:
1. reduced reliability of nutrient pumps of the second rise pumping water with high final temperatures;
2. Complication and appreciation of the nutrient installation;
3. Extensive consumption of electricity to the pumping of water with a higher temperature;
4. Need to synchronize pumps I and II lifting and the complexity of their regulation, because The nutritive pump of the second lift works on hot water, which when the pressure decreases instantly boils.
1.2. Drive of nutritional pumps
There are two versions of feed pumps:
1) electric;
2) turbine.
Electrical Drive Pumps
Advantages:
1) simplicity of design (synchronous or asynchronous electric motor);
2) High reliability.
Disadvantages:
1) limited the unit power of the engine to 9000 kW;
2) limited possibilities for adjusting the feed water.
Turbine feed of nutritional pumps
Advantages:
1) the ability to regulate the speed of rotation, as well as water supply over a wide range;
2) compact;
3) independence from electrical power supply.
The choice of the PN electric motor is based on a thermal and economic comparison of options.
In connection with this, the power of the nutritional pump is determined by the formula:
, (21)
Q P.V. . - feed water consumption, kg / s;
Water pressure drop in the nutritional pump, kg / cm 2;
The average temperature of nutrient water at the exit from Mon, O C;
PDD pump;
Efficiency hydromefet (if it is).
The condition of the thermal economy of a turbine or electrical drive is the following ratio:
(22)
The efficiency of the transformation and transmission of energy during turbita drive and electric drive is respectively equal:
(23)
where - internal relative efficiency of the main and drive turbines;
And - mechanical efficiency of the main and drive turbines;
The throttling coefficient during steam transport in the path of the drive turbine;
CPD generator;
Efficiency of the electric transformer and the electrical network of their own needs;
KPD drive motor;
Efficiency hydromefets.
The electric drive is usually used on the CHP, and on condensation power plants (CAC) the type of drive depends on the power of the power units.
For example:
1) for power units with a capacity of 200 MW and less applied electric drives;
2) for power units with a capacity of 300 MW:
· For ne<30 % - электроприводы;
· At 30% In conclusion, I want to say that the nutritious pump in the scheme of the heat electric station, whether it is classical on natural fuel or a nuclear power plant on nuclear fuel, is an object of increased observation and control and no less important than steam turbine or steam boiler (nuclear reactor) and correctness Its operation also affects the trouble-free operation of the power unit and its reliability. In the next section of the manual, consider the work of the nutritional electric pump from the repair, where the phased entry to work, both the pump itself and all its auxiliary systems: pumps of oil system and oil coolers. 2.2 Starting to work after repair of the oil system of the nutritional electric pump Consider the technological scheme of the strapping of the oil system of the nutritional electric pump (Fig. 15), which can be both autonomous and common to several PEN (nutritious electric pump). Fig.15. Principal technological scheme of the oil system Peng 1, 2 - oil pumps of the lubrication system; 3, 4 - oil coolers, shell-tube; Mm-1, 2 - manometers, such as Obm; P-1, 2 - valves on the recycling line of the oil pump; EKM-1, 2 - electrocontact pressure gauges; MF-1, 2 - oil filters, two on one oil cooler. The oil supply system of Peng is an autonomous system with its oil clock, a group of electric pumps (usually two electricsos, of which one works, the second is on ABR or repair), oil coolers, oil filters, reinforcement, flanges and pipelines, as well as automatic protection and technological locks, and upon failover of one running Peng on the alarm, the reserve Peng is included in the AVR, which has a oil supply system, the oil with a nominal oil level and the system with oil pumps is ready to turn on to work, the cooling water duct is configured through the oil cooler Peng and Maslonasosa to work, the Peng driver adjusts as the oil temperature increases, not allowing it to exceed the nominal value. If it is impossible to regulate the temperature of the oil, urgently connect the reserve oil cooler for cooling water, and the defective output from work, for which it is necessary to close the output fittings on the oil, thereby putting an oil cooler under the crimping pressure with the pressure of the oil pump, and rinse with its refrigeration workshop and inform the coolant (STIC). The oil system of Peng on all thermal and nuclear power plants is largely unified, which simplifies its operation and working capacity, which is especially important for working personnel. The oil system of Peng works as follows. The spent hot oil with a temperature is not higher than 55 ° C of the bearings of the nutrient pump and its electric motor (two sliding bearings from the pump and the electric motor) is returned by the total drain oil of the pumping unit (line "A") in the Peng Maslob, where it comes sucks and Deemulsation, the time of which should be no more than 3-5 minutes, otherwise the oil must be selected for cleaning and replaced it on fresh oil from a nationwide oil supply coming from the central oil utility to the machine room. For lubrication of the bearings of the pump unit, turbine oil is used as for steam turbines, mainly the T-22 or TP-22 brand, the quality of which should meet the requirements of GOST - 53-2000. For reference: (T-22 is a turbine oil (T), with a kinematic viscosity ν \u003d 22 Sortistox; TP-22 is a turbine oil (T), with a kinematic viscosity ν \u003d 22 Santistox with an additive (P) synthetic composition at temperatures 20 0 C. Both brands of oils are distillate oil cracking. The number after the oil grade - 22, 32 or other brands indicates that the kinematic viscosity of the oil is 22, 32 times higher than the kinematic viscosity of distilled water. The time of demulsion shows the amount of water present in the oil And the larger this time, the more clad oil, the smaller its kinematic viscosity. The water aggressively affects the babbate fill of the liner (in Babbit's alloy to 80% tin) of the pump bearings and the Peng electric motor, which leads to the corrosion wear of the liner and decrease its service life. ). After sludge in the oil clock, the oil comes on the aircraft pumps (1, 2). Typically, the oil pumps are mounted in low-speed (up to 3-5 m 3 / h), but with high pressure - up to 30.0 atm (3.0 MPa). It follows that the Pan's oil pumps can be a screw, gear, plunger or other type, which, with incorrect start (especially in Russia), can damage as a pressure oil pressure (rupture of the flange connection of pipelines) and the pump itself (extrusion of pump seals , damage to the pressure and suction reinforcement). Then the pump oil (one pump in work, the second - on the AVR or repair) through one of the oil filters (MF-1, 2), which is connected to the work, the second - in reserve (repair), enters one of the oil coolers, Another oil cooler is in reserve or repair. Here, the oil is cooled with technical water to 40 0 \u200b\u200bs and with an overpressure of 0.7-1.2 atm, it is sent to the total supply oil pipeline, and it is distributed from it into the bearings of the pump and the electric motor, while it is unacceptable an increase in oil pressure in front of the bearings of more than 1.2 atm . With increasing oil pressure in the pressure pipe up to 1.3-1.5 ATM, a mechanical safety valve is installed, which is resetting the excess pressure at the end of the oil line into the oil. To regulate the amount of oil in front of the bearings in the oil supplies, throttle washers are installed, the diameter of which is determined by the experimental pathway, with test launches of the pump after repair and is entered into the pump repair and technical circular. On the nutritional nuclear power pumps in the housing of the pump bearings and the electric motor, a special volume for oil with an annular lubricant is made, which is designed for an emergency separation of the pump unit and to eliminate the booming of babbite fill of the bearings when the oil pumps are turned off when losing its own power unit. Also, many Pengs are widely used by the forefront screws in the form of a multi-hour auger that perform the role of booster (English - Booster, from Boost - raise, raise pressure) and they are installed on the pump shaft before the water entrance to the first step of the flow part of the pump. This makes it possible to partially distorted from cavitation. To prevent mechanical impurities from entering, which may appear from the flows entering the deaerator housing, before the input valve of Peng inside the pipeline, the protective conical mesh is installed, on which the pressure drop of the feed water "to" and "after" the grid is measured. The appearance of pressure drop is more than 2.0 atm., The grid is washed without breaking or unloading the pump for recycling. Protective grids are mounted in a special inset - "coil", which is attached on the flanges in the suction pipeline and can easily be dismantled if necessary. Now proceed to launching the nutritious pumping unit, but at the beginning of the operations on Peng, we will turn on to work with its oil system, without any pump itself, nor its drive. When the oil system is running, it is not displayed in the full repair, it is removed into repair only simultaneously with the repair of the entire pump unit, and this is understandable: without the lubrication system, the pump and its electric drive, having sliding bearings with forced lubrication, will not be able to work. All preparatory and launchers on Peng performs the operational staff of the turbine workshop led by a senior turbine shop (power unit) (STIC) at the direct order of the head of the change of the turbine workshop (NTC) for what: The outfit for the production of repair work on the oil system Peng is closed, and not covered. It usually opens one common outfit for the production of repair work on the entire pump unit: the nourishing pump itself and its oil system, the repair work on the electric motor performs the staff of the power plant, according to the separation statement between turbine and electric workshops. If it is necessary to perform any work within the pump unit, which generally discharged the general outfit, the responsible head of repair work on the general outfit is discharged by an intermediate outfit for repair work on the unit, the unit of the aggregate; In the journal of completion of work (located at the workplace of the NSTC), the heads of electricity, the heat automation and measurement workshops (CTAI), the turbine shop (it makes the last entry in this journal) perform allowing records that all repair work on the nutritional pump unit is completed, The repair personnel of the workshop was removed, the pump is ready for launching. This is the main legal document that gives the right of the NTC to proceed to launch operations on Pane. Nutrient pump driver performs the following job: checks that the repair personnel from the pump unit repair zone is fully removed; checks that the kipia is intact, not expired for the meld, are sealing, connected by pulse lines to the sensors (the root valves on the pulse lines are open), the shut-off and control and protective reinforcement is safe, the piping flanges are connected by studs, which are not rotated from the force of the hand, the coupling and electric motors are closed and closed by a protective casing, oil closed oil rugs closed, oils in the tank no level mechanism (checks the opening of the lower valve leveling glass); reports STIC that the inspection of the pump unit is completed. If there are comments that can lead to an emergency on the pump, then they are recorded in the magazine defects, which is in the workplace of the NSTC, and the launchers are terminated until the repair personnel of workshops are eliminated. The degree of readiness of the pump for the launch is determined by the NSTC, which is responsible for starting the pump; it starts after eliminating defects to inclusion in the operation of the oil supply system of Peng, the Maslobacia is adopted by Khimzech for purity, which is recorded in the NTC operational journal; bringing through the STIC of the supply of fresh oil into the MAN oil, opening the manual valve M-0 (Fig. 15); determines the characteristic noise in the oil clock and on the noise in the respiratory valve on the oil clock, that the oil went into the oil vehicle, the air is displaced through the breathing valve (the breathing valve is a safety device and is intended for sealing the gas volume of the tank with petroleum products and maintain pressure in this volume in specified limits, as well as to protect against the penetration of the flame in the reservoir); The oil leveling glass is connected to the atmosphere, opening the valves of the upper and lower end of the tube, the oil should be poured into the pre-substituted capacity (usually metal bucket) through the bottom end of the tube (usually metallic bucket), after which the valve closes and visually checks oil on its purity and transparency ( To exclude injuries, it is forbidden to use glass dishes, only transparent plastic is used); opens the hand-held valves of H-1.2, closing the valve M-O, when the nominal oil level is reached in the oil clock (usually, on a glass level-level tube, red paint shall be drawn, corresponding to the nominal oil pipe in the oil clock), starts filling of oil pumps by oil, after opening air and Drainages from their buildings, not allowing ingress of oil from air to the foundation and neighboring equipment. When spilling oil on the floor or other places, the oil is removed immediately with dry sand and clean vet. The washed sand and the rags are removed into special metal containers and removed from the workshop; closes the valve when the continuous jet of oil from the air, and drainage, oil pumps are considered to be filled with oil and monitoring; opening the pressure valves of oil pumps (H-1,2), according to pressure gauges (mm-1,2) and EKM-1 checks that they show the magnitude of the static column of oil in the oil clock (0.08-0.10 atm), i.e. The oil level in the tank is about one meter from its bottom. In general, the scale of any pressure gauge should be chosen in such a way that when the pump is running the value of its pressure in the second third of the entire scale; serves technical water to the oil coolers in the summer, opening the manual valves (TV-1,3), as well as air-coolers from the oil coolers, fill the oil coolers of water, (control - from the air conditioner there is a continuous jet of water, air workers to close), put the oil coolers in Water under pressure engineering (control - when opening the valve emptying the oil space of the oil cooler - no water). In the winter season - the tech tub to the oil coolers are not supplied, and at the beginning of the growth of the oil temperature and babbito liners of bearings, gradually submit to the tech industry, not allowing a sharp decrease in oil temperature; outputs on 1/3 output valves Technoda (TV-2, 4) from the oil coolers, puts oil coolers under the duoka engineer; orders the assembly of electricity to the oil pumps; checks together with the Personnel of CTAI protection and blocking on the oil pumps (standard list and purpose of technological protection and power pumps, see Appendix 3); oN 1/2 oil recycling valves (P-1, 2), and suction valves (H-1, 3) pumps, pressure valves (H-2, 4) closed; includes an electric motor of one of the oil pumps, gradually opening the suction valve of the oil pump and its recycling, on the local control panel of oil pumps (MN MN), controls the loading of the pump motor over the ammeter; disables the first broken pump, the second oil pump is in operation, knowing that the operation of oil pumps for recycling more than 30 minutes is unacceptable; inspects during the operation of the oil pumps for defects; asks for SMTTS, what kind of oil pump, according to the workshop schedule, should remain in the work and when the oilsystem is ready for the Pane itself, to apply oil from the working oil pump to the feed collector of the Pan through one of the oil coolers, while gradually closing the recirculation valve, on the M-3 manometer to control the M-3 pressure gauge that the oil pressure at the end of the pressure oil peng corresponds to the nominal value, according to the instruction manual for PEN; switches the key MN key to the "Work Mode Mode" key to the "Work" position, and the backup is to "Reserve", otherwise, on the fact of disconnecting the working pump, the backup oil pump will not be turned on and the nutritional pump will be disabled, which will lead to a violation operation of the power unit; he records the Operational Journal (Daily Statement) of MPEN on the testing of oil pumps of Peng and the state of its oil utilities, reports that the SMTC reports and is waiting for its further orders, not stopping the operation of the oil system of Peng. Chapter 3. Modeling a situation with emergency disconnection of a working oil pump 3.1 Original Status of Equipment In the operation of the nutritious electric pump with one of the two Maslons, the second oil pump is on the AVR), one of two oil coolers (the second in reserve or repair). There are no deviations from nominal parameters. Protection, alarm, blocking and automation of Peng pumping unit are entered into operation in full, as recorded in the operational journal (daily statement) MPEN. 3.2 Possible causes of emergency disconnection of a working oil pump Disconnecting the electric motor of the working oil pump due to faults, for example, from internal damage, short circuit in the terminal box (water entering, breaking the earthing tire of the motor housing), erroneous shutdown by personnel, malfunction of the control circuit, overloading to the current and others. Defects of the pump itself, associated, for example, with the jams of the pump or its bearings, breakdown the impeller, the discharge of the coupling of the pump with the electric motor, the operation of technological protection, etc. 3.3 Scenario of emergency proceedings When a single working oil pump is disconnected, for example №1, oil pressure at the end of the peng pressure line is reduced. In this regard, the value of the oil pressure in the ECM-1 installed at the end of this line reaches the AVR alarm setpoint. Then the ECM-1 block contacts serves an electrical signal in the inclusion circuit of the backup oil pump No. 2, standing on the AVR, the pump unit is turned on into operation without exposure time, replacing the disconnected oil pump. The entire process of passing the ABR and the launch of the backup oil pump to work flows no more than 3.0-4.0 seconds. So - that, a sharp reduction in oil pressure at the end of the oil pressure line of PAN due to the large volume of its volume and the breakdown of the oil wedge in the bearings of the pump sliding and the electric motor will not be. When the nominal oil pressure is reached at the end of the oil line of the PAN and establishing this value in EKM-2, block-contacts on ECM-1 and EKM-2 are placed in the nominal working position and again ready to use an electrical signal to turn on the backup pump when the oil pressure is reduced in pressure line of oil peng. 3.4 ACTIONS OF OPERATIONAL PERSONALS, when disconnecting the working and inclusion on AVR reserve oil pumps The Peng driver will learn about the disconnection of the oil pump on light and sound alarm (revuv) and the loss of the light board on the light panel of the local Panes Control (Peng). After passing around the AVR and turning on the backup oil pump, the Penne driver inspects the inclusive of the oil pump and the emergency disabled, checks the value of the nominal oil pressure on ECM-2 at the end of the oil system of the operating pad of the Operating Pane. In the absence or presence of remarks, MPEN reports the incident of the STIC and NSTC and records this in the operational journal (daily statement) of Peng. If there are clear defects on the disconnected Maslons of the SMTC and the NSTC personally examine the defective oil pump, the NSTC records in the journal of defects and in its operational journal, reports this to the head of the turbine workshop or its deputy manner. 3.5 ACTIONS OF OPERATIONAL PERSONNELS, when disconnecting the working and not inclusion of backup oil pump Peng driver will find out about the disconnection of a working oil pump on light and sound alarm (revuv) and the discharge of the scoreboard on the light panel on the middle of the Peng. Warning signals will not be removed until the driver does not focus them with the acknowledgment button on the Middle Peng, it proves that the emergency signal is accepted. After turning off the working pump and not passing the AVR signal to the backup olon pump (the oil pump did not turn on) MPEN immediately should be recently translated the lock key from the "AUR" position to position - "manual control", and try to turn on the oil pump manually. If you do not turn on the oil pump, immediately translate the locking key of both oil pumps to the position - "Repair", and report the happening of the SMTC event and the NSTC (the position of the "Repair" lock key, imposes a ban on the inclusion of Pane both in place and from the block shield - HOSE). MPEN is obliged to urgently control the emergency stopping of the nutritional pump, while it should go to the opening of an electrified recycling line in the deaerator, and the pressure valve Peng to close. When closing the pressure valve and not opening the recycling valve, immediately remove the power of the valve from the "automaton" and open it manually knowing that more than three minutes of Peng can not work in Russia. According to ECM-1 (on the pressure pipe of Peng), check the zero excess pressure in the pressure line of the stopped Peng, this proves that the feed valve of the pump holds, and there is no reverse rotation (control of the pump coupling). MPEN is obliged to check the normal inclusion on ABR reserve Peng and translate its key locks to the middle of Peng from the position - "AVR", to the position - "work", and take under the enhanced control of the remaining Pan. About all the works of MPEN reports SMTC and NSTC and fulfills a detailed entry in the operational journal (daily statement) Peng and writes in the name of the head of the turbine workshop. A detailed explanatory note on non-AVR in the oil pumps, which the NTC reports. It carefully studies it, analyzes and when disassembling an emergency, explains the staff of the MPEN personnel. The NTC's explanatory note is obliged to transfer to the head of the turbine workshop personally to adopt both administrative and technical solutions. 3.6 ACTIONS OF OPERATIONAL PERSONALS WITH FIRE ON OMELOSIST PEN With the next bypass of the working pumps, the Penne driver discovered on one of them fire oil in the oil clock or on the oil line. MPEN is obliged to immediately report this to the NSTC and the hassle, and independently proceed to steam fire: stop the burning pump by disconnecting from the mains of the nearest button of the KSA (button-stop of the emergency stop running Peng), which must be somewhat and installed in easily accessible places within the pump; include in the work Pump Furniture (NPPHT) with a local key and control that through the foam generators installed above the oil clock or over the Maslian region of Peng, there is plenty of high-time foam, make sure that the focus of the ignition is localized and open. Usually the pumps of the film potential (at least three) are installed in a strictly protected separate building on the territory of the power plant next to the underground reservoir of the storage of the foaming agent. In Russian power plants, several types of foaming agents are used, but mostly those that have a shelf life of at least 36 months. Currently, a number of different foaming agents are produced in Russia, for example, 6CT, 6Ts, 6MT, 6TF (3%), 6Ts-B, 6TF-y, which mainly include aqueous solutions of a mixture of surfactants with stabilizing additives. But all the same, they are all created on the basis of 6 and are designed to extend the fires of classes "A" and "B", i.e. It is for our occasion. PO-6 is a biodegradable foaming agent of the target appointment with an increased fire extinguishing capacity, prepared on the basis of aqueous solution of triethanolamine salts of primary alkyl sulfates with stabilizing additives with a hydrogen indicator pH \u003d 7.0 - 10.0 and the freezing temperature not lower than minus three degrees. But the most stable foams are formed on the basis of protein foaming agents, which are obtained from a variety of substances or fully consisting of protein, or containing it in significant quantities. These proteins are extracted from the blood of animals, skin, bones, horns, hoofs, bristles, feathers, fish scales, oilseed oils, as well as products obtained from milk. In the manufacture of such foaming agents, proteins are pre-hydrolyzed, since the products of their hydrolysis have a much higher foaming ability than the original proteins and proteins. For this, they are subjected to heat treatment, as a rule, in an alkaline medium. Moreover, the hydrolysis is not brought to the end, because The products of the finite decay of amino acid proteins, although quite strong foaming agents, but they give an unstable, rapidly destroying foam. All protein foaming agents are a nutrient medium for various types of microorganisms. Therefore, antiseptics are introduced into their composition - fluorides or phenol. Without them, the foaming agents quickly lose their properties, replete and smell felt. In the production of the foaming agent, the PO-6, the blood of animals, obtained from the meat processing plants, was first hydrolyzed by caustic, then neutralized by ammonium chloride or sulfuric acid. The resulting solution is evaporated to a given concentration. To increase the stability of the foam into the composition of the foaming agent, iron sulfate is introduced. The multiplicity of the resulting foam emerging from the fire barrel with a foam generator, for example, the type of GPS is more than 60 times, i.e. From the unit of the volume of the Po-6 foaming agent, 60 volumes of foam are resistant to about 300 seconds (five minutes) on the fire focus. This time is enough to locate and block free access of atmospheric oxygen, i.e. Stop burning. NPPTs are consumers of reliable power supply and refer to the system security system of the first category, so one of them has a drive from a DC source with a complete loss of its own power plants, i.e. under the conditions of MPa (the maximum design accident) and, depending on the power, be launched from reversible electrical transducers or from nominal batteries; stop the included NPSHT; MPEN in the operational magazine (daily statement) Peng is recorded about the event that occurred; the same actions perform MPEN in a fire on the electric motor or on the pump itself; it is forbidden to extinguish the water of burning electric motors or electrified reinforcement, which are under voltage without dielectric gloves and a special grounding device on the brand. 3.7 Control questions 1. What cases is the AVR of Maslonasosov applied? 2. What is the purpose of the oil filter on the oil coolers? 3. Why should the vortex oil pumps can not be allowed to work in Russia? 4. Apply the need for the recycling line of Peng oil pumps. 5. Create the quality of the used turbine oils. 6. Entry the need for a system of protection and locks on the oil pumps of Peng? 7. Communicate the need for check valve on the pumps. 8. What will the emergency disconnection of the working oil pump and not the inclusion of the backup oil pump? 9. What valuables should the Penne driver do when sunbathing the electric motor or the oil clock of the Peng pump station? 10. How does the Protection of Peng on the axial shift work? 11. Sostaving the foaming agent? 12. Purpose of CSA. Chapter 4. Inclusion in the work after the repair of the nutritional electric pump 4.1 Study of the Technological Scheme Installing the centrifugal nutritional pump performs the following functions: Fence of nutrient water from the DeaErator battery tank; An increase in the overpressure of nutrient water due to high-speed rotation (centrifugal effect) and a stepped sequential increase in water pressure in the pump housing; The supply of nutrient water of such a high pressure, which could overcome the hydraulic resistance of the steam generator water pump path, i.e. more pressing fresh steam from the boiler; Creating a forced movement of nutrient water in the surface of the boiler heating. It is already known that the increase in the pressure of the nutrient water is created due to the centrifugal effect created by the disk working wheel of the pump, with the peripheral location of the blades. For example, if the pressure on the pump suction is equal to the RVS. \u003d 8.0 atm, and on the pressure should be RNAP. \u003d 158.0 atm (the pressure of the acute steam is 130 atm), i.e. The increase in pressure range is: RNAP. - RVS. \u003d 158.0 -8.0 \u003d 150.0 atm, then with a single-stage pump, the diameter of the impeller will be a meter that is unacceptable for reliability and impractically technologically. Let in our case on the Peng rotor installed five stages of pressure increases, in each of which includes an impeller and its guide apparatus with axial and radial seals, then each stage consistently increases the working pressure of water by 30.0 atm. And at the outlet of the pump, this value will reach 158.0 atm. (5 st. X 30.0 atm. + 8.0 atm. On suction \u003d 158.0 atm. On the pressure). In the high pressure pumps and with a one-sided inlet of water during operation, axial hydraulic pressure occurs, which seeks to move the pump rotor (shaft with the impellers planted on it) to the side, the backward direction of the movement of water entering the wheel, i.e. towards the pump of the pump. Therefore, to compensate for the axial force of the rotor shift of the pump in its running part, an axial unloading system is made, which in more detail in the P-5,6 Appendix. Now consider the principal technological scheme of the nutritional electric pump presented in Fig. sixteen. Fig.16. Principal technological scheme of nutritional electric pump 1 - electric camera on the suction of the Pump from Deaerator (B-1); 2 - electrote lock on the pump pressure (H-1); 3 - reverse valve, mechanical (OK); 4 - valve with manual drive on the recycling line in DeaErator (BP-1); 5 - the valve electrified on the recycling line in DeaErator (BP-2); 6 - connecting coupling; A - electrocontact pressure gauge (ECM-1); B - electrocontact pressure gauge (ECM-2); The composition of the nourishing pump with an electric drive includes: 1. Captive centrifugal pump (usually multistage), mounted on a special metal frame, filled with fixed and fixed anchor bolts on a special platform for a plus or zero mark of the engine room of the main building of the power plant. The flow part of the pump consists of two buildings - an internal and external case. The inner case consists of a series of cylindrical sections consistently connected together, each of which has a working step with one impeller and guide apparatus, axial and radial seals. Each section is based on its lit-off paws on the horizontal view of the external case, and all sections are tightened with horizontal through studs, thereby creating a single packet of cylindrical sections. For example, the five-axis nutritional pump has five such cylindrical sections; 2. Suction and pressure flange pipes of pump pipelines with shut-off reinforcement and with a reverse mechanical valve before the pressure valve pressure. The drives of the valves are electrified; 3. Pipeline of feed water recycling line with shut-off reinforcement - two in the course of the valve, the first with a manual drive, and the second valve is electrified; 4. Asynchronous type electric motor. The pump electric motor has built-in air coolers, which, in turn, are cooled with technical water supplied from the common manifold in the engine room of the main power plant building; 5. Connecting coupling consisting of two semi-hummuts planted on a pump shaft and electric motor. Currently, a hydraulic clutch was widely used, which makes it possible to change the amount of rotation of the entire volatility of the pump unit, thereby it makes it possible to adjust the electric power consumption, the supply of nutritional water in the steam boiler, depending on the electrical load of the power unit, which is not possible to do with the asynchronous Drive of Peng (in detail oh hydromule application Fig. P-1,2); 6. The oil susceptibility station of the pump unit, located below the nutrient pump in the basement with its fire extinguishing system; 7. The system of automatic water and foam fire extinguishing of the pump unit; 8. Station of the oil cleaning system (mainly used oil purification methods - poinification (water purification) and clarification (cleaning from mechanical impurities)) for all Peng of one power unit. 4.2 Start Peng to work after repair All preparatory and launchers on Peng performs the operational staff of the turbine workshop led by a senior manist of the workshop (power unit) (STIC) on the direct order of the head of the change of turbine workshop (NTC). The outfit for the production of repair work on the oil system Peng is closed, and not covered. It usually opens one common outfit for the production of repair work on the entire pump unit (the nourishing pump itself and its oil system, the repair work on the electric motor performs the staff of the electric power plant, according to the "separation statement between turbine and electric workshops"). If it is necessary to perform any work within the pump unit, which generally discharged the general outfit, the responsible head of repair work on the general outfit is discharged intermediate outfit; In the journal of completion of the work (located at the workplace of the NSTC) heads of electricity, the heat automation and measurement workshops, the turbine shop (it makes the last entry in this journal) performed the allowing record that all repair work on the nutritional pump unit is completed, the repair personnel are derived , the pump is ready for starting to work. This is the main legal document that gives the right of the NTC to proceed to start-up operations on Pane after repair. The NTC gives the oral SMTC team about the start of launchers on Pen, who, in turn, gives the order of the Peng machine (MPEN). 4.3 MPEN performs the following job checks that the repair personnel from the repair area is derived; removes and refers to the workplace of the NTC warning and prohibiting posters, chains from reinforcement and locks; checks that the kipia is intact, not expired by the meld, are sealing, connected by pulse lines to their sensors, shut-by-control and protective fittings, per capita, piping flanges are connected by studs, the coupling of the pump and the electric motor are closed and closed with a protective cover; includes maintenance station Peng (see paragraphs 2.2. -2.3. of this manual); gives technical water into the electric motor air coolers, opening air and drainage, not allowing water to enter the electric motor body, when the continuous jet of water from air workers appears, to close them immediately; outputs the suction valve B-1 (Fig. 10) by 10-15% of the manual drive and in an open air and drainage from the pump housing, it checks that water from the deaerator comes. Attention! This work must be performed very carefully, not allowing hot water to enter the human body and nearby equipment. After the drainage line and flushing through the drainage line, the aircraft is closed, start heating the metal of the feed pump of the deaerator through the open draenage of the pump, if the deaerator is under nominal parameters, warming up at the speed specified in the instruction manual of the Peng, not allowing the hydrowards in the pump housing Up to the complete closure of the suction valve B-1 when hydrowarders appear; after the cessation of hydrowarders, slowly open the suction valve B-1 and continue the impassion of the pump; to order in TsAI, the assembly of the power supply of the suction B-1 drives, the pressure of H-1 valves and the VP-2 recycling valve into the working position, for the remote control of them from the local and block control panel (HOS); according to EKM-1, it has opened that the check valve OK opened (the pressure gauge should show an excessive pressure in the deaerator housing plus the height of the feed water, equal to the difference of marks, installation of deaerator and peng); fully open the handmade VP-1 recycling valve; when the difference in the temperature of the metal of the pump and nutritious water in the deaerator is not more than Δt ≤ 50 0 s, to fully open the absorbing valve B-1 from the electric drive; open the pressure valves of the pressure valve H-1 (in Fig.16 scheme, not shown) to warm the pump and align the water pressure before and after the pressure valve, so that it can be easily discovered from the electric drive; order in electrical assembly of the electric motor circuit in the test position and order in the CTAI verification of technological protection and locks on the Pane and the electric motor. The check is performed by the operational staff of the turbine workshop (MPEN) and the operational staff of Tsight together. It is necessarily checked by the operation of the emergency button (CSA) stopping the pump with manual posting in place and with the villagers; after checking the protection and locks of the Peng and the electric motor, order in electrical assembly of the electric motor electrode in the working position; after assembling the electric motor electric motor in the working position, the SMTC warns the operational staff of the shop on the Pan launch, turn it on to work with the BSD; MPEN and STICs on the place control the full opening of the second in the course of the BP-2 recycling valve, and the machine driver controls the current load of the electric motor, which should be no more than 30% of the nominal value, i.e. I PAN ≤ 0.3 I NOM.; MPEN and STIC inspect the entire pump unit on the subject of fistula and leaks of water, vibration, yields of kipia, noise, axial valve position electric motor pump. If necessary, emergency stop the pump by pressing the CSA; provided that there is no comments on the work of the pump, give a command to open the pressure gate valve H-1 at the same time checking that the VP-2 recycling valve from blocking from the end switches of the N-1 starts to be closed. On EKM-1, we determine that the pressure on the pump pressure is 5-10% higher than the pressure on the network, i.e. The pump is easy and smoothly in parallel work with other already working Panes and overcomes the resistance of the network; for recycling, it is not allowed to work for a long time on the strength and thermal reasons of Peng; according to a characteristic noise, it is possible to determine that the VP-2 valve closed, and the pump took the total current load, the flow meter shows the nominal flow of nutrient water; with an increase in the air temperature in the air coolers of the electric motor and oil behind the oil coolers of MN PAN, adjust their values \u200b\u200bby increasing the flow of technical water using output valves; establish the position of the key of the mode of operation of the Peng to the middle and the POSE to the "Work" position; MPEN makes a start-up record in the work of Peng in the operational journal (daily statement), and the power unit and NSTC is in their operational journals; Peng is considered to be commissioned after repair, if he worked without comments with nominal parameters continuously at least 72 hours (three days); according to the workshop, the Peng should not continuously work more than 30 days, so it is necessary to perform a planned transition to the reserve fan. To create equal working conditions for all PEN of the power unit, the frequency of output to the reserve of working pumps is determined than the same pumping of pumps and the uniformity of their wear is achieved, and the reliability of each pump in long-term operation is checked. But in any case, the backup Peng must be good and in constant readiness for the start, so the valves at the input and output pipelines must be open, the AVR check should be carried out periodically according to the schedule at least once in the calendar month, the capital repairs of Peng must be carried out at least Once every three or four years. 4.4 Control questions 1. What functions do the nutritional pump in the power unit scheme? 2. On what physical effect is the method of increasing fluid pressure in the nutritional pump? 3. Why increases the temperature of nutrient water in Pen? 4. What does the quality of the deaeration of nutritious water depend on? 5. How is the axial shift of the Pan Rotor? 6. Describe the main stages of starting to work Pan? 7. What devices are provided to prevent the pump rotation? 8. Enough the need for Peng Recirculation Line? 9. What is the ECM on Pan? 10. What is dangerous for the staff the appearance of fistulas on Pan? 11. What are the inclusion schemes on the power unit? 12. What unloading devices are available on Peng when started to work? Chapter 5. Collaboration of two or more nutritional pumps on a general hydraulic network In this chapter, we will look at the collaboration options for centrifugal nutrient pumps, both with sequential and parallel inclusion on the overall hydraulic network. Usually, the parallel operations include pumps, on which the duration of operation, reliability, efficiency and safety of the operation of the operated power unit depends. Such pumps include nutrient, condensate, circulating pumps, turbine lubrication systems, generators, fire and other pumps. To simplify the energy installation device, with parallel operation, the same type pumps are usually used, which allows you to expand the water supply range to the network. The need for consistent operation of pumps arises mainly to ensure favorable conditions for suction to a more powerful pump due to less powerful. For example, the use of boosters and transparent pumps can significantly reduce the mass and dimensions of the main nutrient pump. The need for sequential inclusion of pumps may appear when one pump under consideration cannot create sufficient pressure. 5.1 Parallel operation of centrifugal pumps Pumps in pumping stations and in large pumping installations, as a rule, work together, i.e. Several pumps supply liquid into one hydraulic system. In this case, the pumps can be included in the system sequentially (sequential operation) or in parallel (parallel operation). Parallel is called joint and simultaneous operation of several pumps attached by pressure pipes to a common hydraulic system. To avoid the phenomenon of the surge, it is best not to use such pumps with parallel inclusion, in which the pressure characteristics have uptreten. These include pumps, whose working wheels have a ratio of 500 ≥ N s ≥ 80. 5.2 Parallel operation of centrifugal pumps with the same characteristics In fig. 17 (a) depicts the consumption-pressure characteristic Q - H of each of the two identical pumps. In order to construct the total characteristic of these two pumps with parallel operation, it is necessary to double the abscissions of the curve Q-H of one pump with the same ordinates (heads). For example, to find a point in the total characteristic Q - H, it is necessary to double the segment (AB). Thus, the segment (AV \u003d 2AB). Other points of total characteristics also find. Fig. 17. Characteristics of parallel operation of two centrifugal pumps in one system A). pumps with the same characteristics; b). Pumps with different characteristics To determine the mode of joint operation of pumps, the characteristic of the R - E system should be built in the same way as when one pump is operating. The operating point in this case will be on the intersection of the total characteristics of the pumps with the characteristic system. The total feed in parallel operation of the two pumps is characterized by an abscissa point 2 and is equal to q i + i 1, the pressure corresponds to the ordinate of point 2, equal to H i + i 1 or H i. To set, in which mode each of the pumps work, it is necessary to spend from point 2 line parallel to the abscissa axis. The abscissa corresponding to the intersection point of this line with the Curve Q - h of the pump (point 1) will determine the flow rate, and the ordinate is the head of the H i of each of the parallel pumping pumps. Consequently, the pressure, developed by each pump, is to a step developed by two pumps during their parallel operation, and each pump's supply is equal to half the total feed of two pumps. If only one pump was supplied to the liquid in this system, then the mode of its operation would be prescribed and the feed at point 5. As can be seen from fig. 17 (a) In this case, its feed Q 0 would be more than in the case of parallel operation with the second pump. Thus, the total supply of pumps operating in parallel in the overall system is less than the amount of the submission of the same pumps during their separate work. This occurs due to the fact that with an increase in the total fluid flow into the system, the pressure loss increases, and therefore, the pressure required to feed this consumption increases, which entails a decrease in the supply of each pump. The efficiency of each of the parallel pumping pumps is characterized by its efficiency at point 4 at the intersection of the curve Q - η with a perpendicular, lowered from point 1. As can be seen from fig. 17 (a), the efficiency of each of the parallel pumping pumps is also different from the PDD of the pump during separate work, which is characterized by the efficiency at point 3 on the curve Q - η. The power of each of the parallel pumps is characterized by a power at point 7 on the Q-N curve, while the power of a single working pump is determined by the power at point 6. When constructing the total characteristic of the three parallel pumping pumps, the abscissa characteristics of each pump should be tripled. The mode of operation of three and more pumps with their parallel inclusion is defined in the same way as in the case of parallel operation of two pumps. With an increase in the number of parallel pumping pumps or with an increase in the resistance of the system, for example, when one of the sections of parallel water pipelines are turned off, each pump is separated separately. The parallel operation of the same pumps into one system is effective with the gentle characteristics of the system and the steep characteristics of the pumps. With a steep system characteristic, parallel operation may be ineffective, since when connecting to one pump, the second or third pump feed will increase slightly. The same pumps for parallel work on catalogs should be selected so that the optimal point of characteristics correspond to the pressure calculated to supply the entire flow to the system, and the supply equal to the total flow rate divided by the number of the same pumps included. With parallel operation of two pumps, their overall performance is less than the double performance of one pump. Usually, when operating one pump, the feed is 60% of the total feed when parallel to the operation of two pumps. The slope of the curve is determined by the loss of pressure on overcoming resistance in the pipeline. It is known that the magnitude of the loss is inversely proportional to the diameter of the pipeline in the fifth degree (ΔH ≡ 1 / d 5 of the pipes.) Or with a large diameter of the pipeline for skipping the same costs, smaller pumps are required, while the network characteristic will be used. Therefore, the pressure and dumping waterways of circulating water on power plants are performed from large-diameter pipes. With a small diameter of the pipeline, large pumps are required, while the network characteristic will be cool. You can adjust the new pump to the specified value of Q., But with less pressure, with a slight decrease in KPD. - Wheel with cutting wheels, if there is no spare impeller with a smaller diameter. When operating pumping equipment on power plants, it is often necessary to change the pressure-consuming characteristics of the current pump without buying a new pump. In this regard, it is necessary to draw trimming wheels of the existing pump. But in order to avoid a significant decrease in KPD. Pump Reduction of the diameter of the working wheels of the centrifugal pump is limited to the following limits (Table 1): With NS\u003e 350, working wheels are usually not performed. With enough for practical targets with an accuracy of 2-5% definition, a decrease in the diameter of the impeller is made according to parabole proportionality, built by the formula: H \u003d Hn. Q 2 Star. / Q 2 new \u003d BQ 2 old. (25) The value of the new diameter of the DNAs. Determined by the formula: DNA. \u003d Q. / Qstar. (26) DNA. \u003d DSTAR. Öhnov. / HSTAR. (27) nS \u003d (365NÖQ) / N 3/4, (28) where q is the pump consumption, m 3 / sec; N - pressure pump, m.vd.st.; n is the number of revolutions of the pump, rpm. Usually, if: nS ≤ 60 are low centrifugal pumps; nS ≤ 70-150 is normal centrifugal pumps; nS \u003d 150 - 360 is high-speed centrifugal pumps with a maximum kp.; ns \u003d 350 - 650 is diagonal pumps; nS \u003d 600 - 1200 is a high-feed axial pumps. When determining NS pumps with double-sided absolution, their performance is divided into 2, and multistage pumps - the pressure is divided into the number of working wheels. 5.3 Parallel operation of centrifugal pumps with different characteristics Pumps with different characteristics can work in parallel only under certain conditions, depending on the ratio of the characteristics of these pumps. Analyze the possibility and feasibility of parallel operation of pumps with different characteristics, you can combine pumping characteristics and systems. Figure 19 (b) shows the characteristics of pumps I and II. As can be seen from the figure, the pump II develops a smaller pressure than the pump I. Therefore, the pump II can operate in parallel with the pump I, only starting from the point where the head-develops are equal to (point F. 17 (b)). Characteristics of the joint operation of pumps (total characteristic), starting from point C, is built by adding the abscissity of the characteristics of pumps I and II with the same ordinates (heads developed by pumps). To determine the total feed, it is necessary to construct the characteristic of the system (the curve of the re fig. 17 (b). Then from the point A - the intersection points of the system characteristics with the total characteristic of the joint operation of pumps I and II should be carried out with a line parallel to the ordinate axis that cuts off on the abscissa axis segment corresponding to the flow rate Q I + I 1 supplied to the system with both pumps. The supply of each of the joint working pumps can be found by spending from the point A direct, parallel axis of the abscissa. The intersection of this direct with the characteristics of pumps I and II gives the corresponding points 1 "and 2 "The values \u200b\u200bof feed Q" I As in the case of parallel operation of two pumps with the same characteristics, the total feed of two pumps is less than the sum of the feeds of each of the pumps separately. From fig. 17 (b) it can be seen that q i + q i\u003e q i + ii. The power and efficiency of jointly working pumps are determined in the same way as in the case of a joint parallel work of two pumps with the same characteristics. The principle of constructing the characteristic of parallel operation of different pumps is used to construct the characteristics of parallel operation of several identical pumps, when the supply of one of them is adjusted by changing the speed of rotation. 5.4 Inclusion in parallel operation of two nutritional electric pumps Now consider the option of inclusion in the parallel work of Peng with a friend of Pane, and what conditions must be followed. The first and most necessary condition is that the pressure of the included pump exceeds the operating pressure on the network at least by 10-15%. Otherwise, the pump will not be able to enter the network, and will work at idle in Russia, which is tantamount to the closed pressure valve. We already know what it can lead to, and that such a mode of operation of the centrifugal pump will not allow more than three minutes. Figure 19 shows the inclusion scheme in parallel operation of two nutritional pumps, while they have the same pressure-expenditure characteristics, the same type and both are fit. Usually, with this circuit on the inclusion of pumps on the general hydraulic network, one of them is in operation, and the other on the AVR or in repair. Consider the following variant of the state of the original scheme in Fig.18: PEN-1- in operation, and PEN-2 - it is necessary to turn on after repair. The work performs the operational staff of the turbine workshop - the eldest driver of the workshop (STIC) and the driver of the nutrient pumps (MPN). Fig. 18. Inclusion scheme in parallel operation of two nutrient pumps PEN-1,2 - nutritional pumps; PT-1,2 - suction valves of nutritional pumps; OK-1,2 - check valves of nutritional pumps; NZ-1,2 - pressure valves of nutritional pumps; BP-1,2 - recycling valves; WB-1,2 - bypass valve pressure valve. ECM-1,2,3 - electrocontact pressure gauges. In the head of thermal automation and measurements (CTAI) to order an assembly of the power supply of the drilling (PT-2), pressure (NZ-2) valves and recycling valves (BP-2); Include in the work system of oil supply PEN-2; Slowly opening the suction valve VZ-2, fill the pump with hot nutrient water from DeaErator, knowing that its temperature is about 160 o C, gradually warm up the pump, not allowing hydrowards, and warming up the heating control to the thermometers on the local pump control panel; Through Bypass of the WB-2 pressure valve NZ-2, fill out and warm the pressure pipe from the total network pipeline and thereby unload the pressure valve from one-sided pressure from the pump to the pump. If this unloading does not perform, then the pressure valve of the NZ-2 will be difficult to open with the help of an electric drive, which will "sit on the coupling", which will lead to knocking out the drive of the drive from the current overload and to the launch of the pump start and even to the failure of the NZ valve electric drive -2; According to EKM-2, it is determined that PEN-2 is filled with water and warm (the temperature of the pump metal is determined according to the testimony of the measuring device on the local PEN-2 control panel, which is located next to the pump). It is forbidden to warm up air drifts to warm up the pump, it is allowed to open the drainage valve from the pump housing, after warming up - close it; Scroll from the electric drive pressure groove NZ-2 and VP-2 recirculation valve; Through the head of the shift of the electric temperature to order the assembly of the PEN-2 electrical circuit in the test position; Together with the Ktai staff, check the triggering of technological protection and locks on Peng-2; Through the head of the shift of electrotsery, order an assembly of the electric motor of the PEN-2 electric motor into the working position; Check that the suction valve PZ-2 is open completely, the pressure gauge is closed, but its drive is collected, the handmade valve on the recycling line is open, and the valve with an electric drive is closed, but the diagram of its electric drive is collected, drainage and fleet of pumps are closed, bypass pressure valve NZ -2 closed; Includes in the work of the PEN-2 electric motor, according to the ammeter on the local shield of Peng-2, we see that its arrow on the red feature, which testifies - the pump works on the closed pressure, control the automatic opening of the recycling valve from the electric drive, on EKM-2 check that pressure , created by PEN-2, is higher than the pressure on the ECM-3 network. This indicates that PEN-2 will overcome the resistance of the network and freely enters parallel work with the PEN-1 pump; After three minutes, it should automatically go to the opening of the pressure gate of the NZ-2, and the VP-2 recycling valve should go to the closure. If it does not respond to the work of the reinforcement, MPEN is obliged to manually open the pressure valve from the local control panel of Peng-2. In this case, the key lock is translated from the "Local" control "Local" and manually close the recycling valve - BP-2; On the ammeter on the local control panel of Peng-2, control that the electric motor took a current load, the arrow of the device "fell off" from a red feature to a smaller side and was established on the value of the nominal value of the electric motor operating current; Another 20-30 minutes, it is necessary to control the work of the PEN-2 pump unit, special attention to the current load, the temperature of the pump metal, the operation of the PEN-2 oil system, the axial shift that all the readings of the standard control and measurement devices are in the limit of workers. MPN records the time of Peng-2 to work in the daily statement and reports the work of the STIC. 5.5 Control questions 1. In which operational documentation, technological operations are performed on equipment? 2. What does it mean to "sit on the coupling"? 3. PURPOSE OF THE LINE OF THE BYPAS POINT SPORATVIVE PEN? 4. Appointment of ECM on Peng? 5. What is hydrothera? 6. How can the hydrowood in the pump be avoided? 7. Appointment of deaerator? 8. Why are you needing condensed screws, augers? 9. Appointment and work of the check valve on Peng? 10. Required pump entry conditions in parallel work? 11. Why and when are the pitching of the pump impeller? 12. How can one determine the total performance of two pumps operating in the parallel? Applications Outfigure-tolerance (outfit) is a task for the production of work, decorated on a special form of the established form and the defining content, place of work, the time of its start and end, the conditions of the safe conduct, the composition of the brigade and the person responsible for the safe performance of work. Atomic power plants are issued a dosimetric outfit. Dosimetry outfit is a written task for safe work. In the outfit, the admission indicates the content of the work, the location and time of it, the necessary security measures and the composition of the brigade. When performing work on dosimetric outfits, admission are prescribed responsible persons for the safe conduct of work. A penalty-tolerance person is responsible for the possibility of safe work and completeness of the predetermined radiation safety measures. Security measures are determined based on the results of the measurement of the radiation situation and are recorded in the column "Conditions of the work of work", and the necessary SIZ complexes are indicated in the "Additional Protection Tools" column. The manufacturer of the work is responsible for acceptance of the workplace in accordance with the requirements of the admission, and compliance with radiation safety measures personally and members of the brigade for the decontamination of the workplace after the task is fulfilled to permissible levels. Advanced is responsible for the full implementation of radiation safety measures in accordance with the outfit-tolerance, the correctness of admission to work and acceptance of the workplace at the end of work. The dosimetrist is responsible for the correctness of the measurement of the parameters of the radiation situation before the admission of the brigade and during its operation, periodic monitoring of compliance with radiation safety measures working in the work of work. The members of the Brigade are responsible for compliance with radiation safety measures and the proper use of PPE, provided for in the outfit. The order is also a task to safe work. It is drawn up in the journal of registration of outfits and orders and has one time. The deadline for the disposal is determined by the duration of the work day of the brigade. The list of works performed by outfits-tolerances or orders is approved by the leadership of the power plant. Admission shape Enterprise _________ Division __________ Outfit, shared outfit, intermediate outfit N ____ _________________________________________ To the general along N ______ (filled only when issuing an intermediate outfit) Head of work _____________________________ Manufacturer of works (observing) _________________ (unnecessary cross) (surname, initials, position, discharge) with members of the brigade _____ people. __________________________ (surname, initials, discharge, group) Hardware _____________________________________ ________________________________________________ Getting Started: Date ____________, time ____________ Ending: Date _________, time __________ To ensure secure conditions, it is necessary to ____________________ (The necessary workplace training activities and security measures are listed, including those subject to duty personnel by other workshops) Special conditions ______________________________________ Outfit issued: date ________, time ________, position Outfit extended by: date ______, time _______, position Signature __________________, surname, initials date Time ______________________ The work conditions are completed: date _______, time Remain in work ____________________________ (Equipment located near the place of work and is under voltage, pressure, at high temperature, explosive, etc.) Duty staff of other workshops (plots) _____________ (shop, position signature, surname, initials) Mark on the resolution of the head of the change of power station (dispatcher duty) ____________________________ (signature or mark on the resolution transmitted by phone, the signature of the head of the shift of the workshop) Responsible person of the staff of the workshop staff (block, district); head of work on the interim alongside (unnecessary cross) ______________________________ The performance of the work of the work was checked, with the equipment remaining in the work, acquired and was admitted to work. Date Time ______________ Performance Manager ____________________________________ Manufacturer of work _____________________ Registration of daily tolerance for work, completion of work, translation to another workplace. The work is completely finished, the brigade is removed, grounding, installed by a brigade, discontinued, reported (to whom) ___________________ Date Time______________ Manufacturer of work (observing) ______________________ Responsible Manager of Works ____________________ Standard technological protection and locks on Peng. Consider existing protection, blocking and signaling on the example of the feed electric pump of the SPE-1250-75 type, used both on thermal and at nuclear power plants. Currently, other types of Peng are also applied, but the principle of building protection and blocking with alarm deviation of the operating parameters of the pump unit remains the same: maximize the safe operation of the pump unit - the nourishing pump-electric motor Heat engineering: Reducing the pressure of nutritious water on the pump pressure less than 40 atm. - The trigger comes from ECM installed on the middle. During the pump start, the protection pad is automatically displayed from work for 30 seconds. Increased pressure in the axial discharge chamber of the pump more than 12 atm. - The triggering of protection comes from ECM installed on the middle. Reduced oil pressure at the end of the oil line less than 35 atm. - The trigger comes from the ECM installed on the Middle, the time of shutter speed of protection - 8 seconds. Electrical protection: Differential protection of the electric motor from between the phase short circuit - without delaying time acts on the disconnection of the pump electric motor switch; Protecting the minimum voltage when lowering the supply voltage at: Umin \u003d 0,65Un., Oil circuit breaker is turned off with a time shutter speed of 35 seconds; Umin \u003d 0.45Un., Oil switch is turned off with a time shutter speed of 7.0 seconds; Protection of the electric motor from current overload when reached the reloading current of the iPer. \u003d 1.5In. Protection triggers with time shutter speed longer starting current time. Protection of the electric motor from the closure of the winding of the stator "to the Earth" - only a warning signal on the middle of the Peng is coming. Locking Peng: Turning on the pump is held up to: Increasing oil pressure in the lubrication system of more than 0.5 atm and the opening of the feed water recycling line in the deaerator; With a decrease in nutritious water consumption less than 400 m 3 / hour - recycled valves from NMD on Peng Mid; With feed water consumption of more than 480 m 3 / hour - the recycling line is closed into a deaerator; ABR Maslonasosov Peng occurs: On the fact that the operating pump is turned off; With a decrease in pressure on the head of the oil pump less than 1.8 atm. - the signal comes from ECM installed on the middle; With a decrease in the pressure of the lubricant of 0.5 atm. - turns on the reserve oil pump; With a decrease in the pressure of the lubricant of 0.35 atm. - Turns off Peng. Alarm deviations during normal operation of Peng. Reducing the pressure of nutritious water on the pump pressure less than 82 atm. A flashing sign on the pump migrant appears on the Hazus; Reducing the oil level in the Peng oil less than 0.1 m from the nominal level - the warning blink is falling onto the scent of Peng, a beep is fed; The increase in the oil temperature at the entrance to the bearings of the pump unit is more than 45 o, the warning bibnaker on the scent of Peng is given, a beep is fed; Increasing the temperature of the oil on a plum from the bearings of the pump unit of more than 70 o C - the warning blink is falling onto the village of Peng, a beep is served. Peng with hydromefta. In fig. P-1 is Peng, where a hydraulic clutch (hydromefta) is shown as a coupling as a coupling. Fig. P-1 General view of the nutritional pump assembly Fig. P-2. Pump unit Peng with hydromefta A - Block of the automatic control system (ACS) and oilsets hydromeflues. Fig. P-3. Hydraulic coupling Fig. P-4. Energy saving from the use of hydromefta From the analysis of graphs in Fig. P-4 it follows that at small penneers, the maximum power savings on its drive from an asynchronous electric motor is achieved, which cannot be obtained during rigid couplings. This is especially important when the power unit is often unloaded up to a complete breakdown on mode or dispatching graphics, or when the power unit is involved in regulating the power of the power system, usually at night. This possibility of regulating the power and supply of Peng is also important when starting and stopping the power unit, which gives significant energy savings on its own power plant needs. PEN axle unloading system. In the pumps with one-sided inlet of water during operation, an axial hydraulic pressure occurs, which seeks to move the pump rotor (shaft with the impellers planned on it) to the side, the backward direction of the water movement entering the wheel. How can I balance the axial effort? This can be achieved: 1. two-way water input to the impeller, and in a multistage pump - the corresponding group arrangement of the working wheels on the pump shaft (mixed type); 2. Drilling holes in the rear wall of the impeller, through which there is a decrease in the difference of efforts acting on the external and inner wall of the impeller, in this case the wheel has seals from both sides, but these drills are reduced by kp. Stages and in modern pumps this method of axial unloading is almost no applied; 3. Hydraulic height device in multistage pumps. Due to the fact that the first two methods do not apply in the nutrient pump device, we will consider only the third method of balancing axial effort - this is a hydraulic height device in multistage nutritional pumps. How the hydraulic fifth of Peng works. The hydrophitic is a massive disc, fixed on the pump shaft for its last step. In fig. P -5 is a scheme of operation. Hydropic: water from the pump input chamber (a), passing through the ring gap (3) and the radial clearance (b), enters the chamber hydropytes (4), which goes into the chamber connected to the atmosphere or from Suction tube pump. Fig. P-5. Circuit diagram of the axial unloading of the nutritional pump 1 - last in the course of nutritious water the impeller of the pump; 2 - Hydropa washer; 3 - ring gap; 4 - Camera Hydropic; 5 - Disk Hydropic; 6 - hydraulic seal of the pump shaft; A - inlet of nutritious water from the impeller; B - radial clearance (when pumping a pump - no more than 0.15-0.20 mm); B - dynamic effort displacement of the pump rotor towards the pressure; G is an effort of the hydraulic unloading of the pump rotor towards the VSAA. The axial force in modern nutritional pumps is directed toward the VASA of the pump and is somewhat tons. Therefore, the unloading of axial efforts is carried out using hydropytes (discharge disc), the operation of which is given in the application in Fig. P-6, where it is shown that for the axial unloading of the pump, the vector and the axial displacement of the pump rotor is directed towards its VSAA (the pressure of the pressure is 16 times greater than the water pressure on the USHE - vector B, p 2 \u003d 8 atm), on the shaft The head sides are installed unloading monolithic disk, in the chamber of which, nutrient water is supplied from the pump pressure in the opposite direction of the displacement vector. Fig. P-6. Scheme of the unloading chamber and forces acting on the discharge disk Malfunctions of nutrient pumps Mechanical damage and malfunction of nutrient pumps occur due to: Unsatisfactory repair and maintenance; Improper assembly, centering and drive, balancing during installation, poor bearings lubrication; Errors when starting and stopping. To serious consequences can lead: The absence of or incorrect device and the use of discharge lines of nutrient pumps; Lack of or fault of check valves and flow limiters on unloading lines, including them into a common unloading pipeline and in the suction line of nutrient pumps. To ensure reliable operation of nutritional pumps, the factory guarantees their good job, taking into account the use of spare parts for at least 12 months. From the date of commissioning for condensate pumps with a supply of up to 20 m3 / h and at least 24 months. For all other pumps, subject to the rules for transportation, storage, installation and operation. Preservation of pumps, spare parts are produced in such a way that their protection against corrosion is provided during transportation and storage without reconservation for two years. In addition, all holes, the connecting flanges and pump nozzles are closed with corks or plugs, and the responsible connectors and the openings of the inlet and pressure pipe are sealing. In pumps weighing more than 1000 kg or on their foundation frames (stoves), control devices are provided for the reconciliation of their position on the foundation and place to set the level. Places to set the level are indicated on the mounting drawing. Before testing the pump, an electric motor is separated separately to verify the direction of rotation, the lack of vibration, the temperature of the bearings, after which the demumufts are connected, and the joint operation of the electric motor with the pump at the beginning is at idle, and then under load. Wheels and rotors assembly need to be balanced. The rms value of the vibration velocity measured on the housings of the pump bearings should not be more than 7 mm / s in the manufacture and 11 mm / s - during operation, and the temperature of the metal and the bearing oil should not be more than 35-40 ° C above the temperature ambient air. It is necessary to ensure continuous supervision of their good condition during the operation of nutritional pumps. Regularly check the pump control and measuring instruments, maintain the pressure of the nutrient water after the pumps and control the water pressure before the pump in accordance with the instruction manual for the pump. Sit down from valves on injection pipes pumps posters with an inscription that the discharge line must be included: When starting the pump; When working at idle; When the load is reduced to the maximum permissible pump operation of the pump according to the production instructions, but not lower than 20% of its nominal productivity. In addition, there is a diameter and deaeration scheme in the workplaces with all related to them and reinforcement, instructions for servicing installations associated with steam boilers. The instructions necessarily indicate the procedure for the action of personnel to prevent and eliminate possible problems and accidents. It is not allowed to include a nutritional pump, as well as its work at idle, with a closed valve on the discharge side without a waterproof along the recycling line (unloading) for more than three minutes. It is important to ensure that the reserve nutrition pumps are open on the suction and injection pipes. When the pump is output, it is necessary to turn off its electric motor only after closing the discharge valve (with a preliminary opening of the recycling line). If the nutritional pump remains in the reserve, it is necessary after its complete stop again open the valve on the discharge nozzle and check if the engine rotor rotates. If, in the case of the reverse valve, the pump rotates in the opposite direction, then it is necessary to immediately close the injection valve from the pump and take it into repair. ABR must be equipped with an automatic device for starting the backup pump with a decrease in pressure in the pressure line and periodically, according to the schedule, check its action (necessarily for all power pumps with an electric drive). In addition, it is installed from each nutritional pump a separate recycling (unloading) line with a restrictive washer connected to the deaerator or nutritional bac (but not to the suction line of nutrient pumps). The removal line is made to the pump check valve. If the unloading lines for the same type pumps are combined, then the check valve is installed on each of them. A combination of unloading lines of electric and turbo-pumps is prohibited! It cannot be allowed when the nutritional pumps can be used to increase the temperature of bearings and their drives above 70 o C, if necessary, replace lubricant in bearings or in the lubrication system. Noise and blows in the pump are observed at: With incorrect boring of connecting semi-humull; Static shaft deflection; Bearing knocking; Turns of closure in the electric motor; Crushing the impeller for seals; With invalid heating of bearings; When cavitation appears. A noticeable reduction in pump performance after a while of its normal operation can be caused: Increasing slit loss inside the pump; Increase in water temperature; Large pipeline resistance on suction (pumping pump); Clogging the impeller and its wear; Air entering the pump and suction pipeline. Nutrient pumps are placed below the drugs of the deaerators in order to avoid breaking the flux of hot water due to its boiling. The formation of steam bubbles in the suction pipe of the pump leads to hydraulic shocks in nutrient pipelines and breaking the water supply by the pump, which can cause an accident. The main reasons for "bearing" Peng are: 1. A sharp decrease in water level or pressure in Deaerator; 2. Recessed reduction in nutrient water consumption with a closed recycling line; 3. Recessed increase in nutrient feed supply by pump when clogged the grid on SCASS; 4. Improvement of resistance on the unloading line from the chamber hydropytes; 5. Washing leaks through the chamber hydropytes. Consider only two main reasons, because In no case cannot be allowed to "bearing" the pump, which can quickly lead to its failure. 1. A sharp decrease in water or pressure in the deaerator. This can be caused by: 1.1. End structures of the electronic level gauge readings, check it and duplicate by the level of the engineered glass installed in the battery pot of the nutrient water; 1.2. clogging the filter grid on the pump suction. The filtering mesh on the USSU PEN has two conical housings inserted one in another, between which the brass grid is clamped. The inner conical mesh case consists of vertical wire rods with a diameter of 6.0 mm with a wired with a wire with a diameter of 1.0 mm. The outer conical mesh body is made of perforated sheet steel with a thickness of 4.0 mm with 22,000 holes with a diameter of 4.0 mm. For periodic filter purge and its washing there are two main condensate supply pipe from condensate pumps and dirt removal from the bottom of the filter. The purge can be made when the pump is running, and the washing only on a stopped pump; 1.3. Conversion of the regulating valve of supply of the main condensate. It is urgently to check whether the diagram of the regulator's electric drive is collected, immediately contact the driver by the Machinist on deaerators, to manually open the conneveter bypass and check the opening of the fixture of the main condensate through the chiller of the deaerator. A sharp decrease in the level of nutrient water in the DeaErator's battery pot when the nutritional pump is running, can lead to the formation of a funnel on the pump suction and to its breakdown, because The pump on a water pair cannot work; 1.4. The closure of the heating steam regulator in the DeaErator leads to a decrease in the pair pressure in its case. Urgently open the bypass of the regulator, check manually operation of the regulator itself; 1.5. It is not authorized opening an electrothematics digging of cold himobassive water into a deaerator for emergency feeding and pre-filling deaerator. This leads to a sharp decrease in the pair pressure in the DeaErator and can lead to the boost of the entire volume of water in the deaerator housing and to its destruction. 2. A sharp decrease in nutritious water consumption with a closed recycling line. This can be caused by: 2.1. improper reading of the flow meter, check its readings; 2.2. spontaneous closure of pressure valve from short circuit in its electric drive; 2.3. The connection of the connective clutch electric motor-pump. Urgently check the current load of the electric motor. When climbing clutches, the ammeter will show a current of the idling of the electric motor, i.e. Less rated current. A mechanical check valve is installed on the pressure pipe of the pump, which serves to prevent the pumping of the pump with a decrease in the feed water. The check valve is equipped with an automatic recycling line, which provides consumption of at least 30% of the nominal flow rate of the pump with a closed pressure valve. The "bearing" of the pump is expressed by the occurrence of metal contact between the fixed and rotating parts of the pump as a result of the breaking of the stream of water, from which the intensive vaporization appears in the pump. With "bearing" there are strong blows and noise at the inlet of water into the pump, a decrease in pressure on the pump pressure, a sharp fluctuation of the current load of the pump motor. PE-type nutritional pumps provide water supply with a temperature of up to 165 ° C into drum and direct-flow steam boilers and are designed to supply water of stationary steam boilers of thermal power plants operating on organic fuel. Pumps with nominal supplies 380 and 580 m 3 / h can be operated with hydromefta and without it; 600 m 3 / h - only with hydromefta; 710 m 3 / h - without hydromeflip; 780 m 3 / h - can be completed with synchronous frequency controlled electric drive. A group of nutritional pumps also includes pumps of two types of PE and FAQs and are designed to supply steam boilers with water that does not contain solid particles. Structurally, they are horizontal sectional multistage pumps with one-sided location of the working wheels and are divided into one-circuit and two-circuit. Six-speed single-populated PE65 / 40 pumps, PE65-53, PE150-53 and PE150-63 are designed for boilers with a pressure of 40 kgf / cm 2. Flowing part of gray cast iron sch20. Ten-precinct single-populated PE270-150-3 pump is designed for boilers with a pressure of 100 and 140 kgf / cm 2. Flowing material - steel. The shaft supports serve two sliding bearings with water cooling cameras. The pumping of the pumps is provided by the cooling of the oil seals. Water is supplied to the seal assembly for the condensation of the vapor of the pumped liquid, which may be seized through the seal. The axial force acting on the rotor of the pump is perceived by the hydraulic fifth, cast from the modified cast iron. A two-circuit design represents pumps: ten-speed PE380-185-3, π500-180-3, π580-195 and eleven-speed PE380-200-3 for pretritic boilers with a steam pressure 140 kgf / cm2, seven-step PE600-300-3 pump for core boilers with Paper pressure 255 kgf / cm2. Digital pump designation: first digit - supply M3 / hour, second - pressure in kgf / cm2 (atm). With the development of atomic energy, special nutritional pumps were created for nuclear power plants, which are not intended for a wide range of consumers and are indicated by the letter A, i.e. only for nuclear power plants. The nutrient centrifugal-vortex cantilever pumps of the FA type are designed for pumping water and other neutral fluids with a temperature of up to 105 ° C containing solid inclusions of up to 0.05 mm in size, a concentration of no more than 0.01% by weight. Fig. P-7. PE nutrient incision type (nourishing with electric drive) 1 - shaft, 2 - bearing, 3 - fetal seal, 4 - inlet cover, 5 - ring supply, 6 - anti-wheelchair, 7 - Cover, 8 - impeller, 9 - section ; 10 - guide apparatus, 11 - pump casing, 12 - internal housing, 13 - pressure cap, 14 - case of a terminal sealing shaft; 15 - rotor stop, 16 - discharge disk; 17 - auxiliary thrings; 18 - Outer buildings, 19 - stove. Fig. P-8. Floor type pump cut: 1 - cover, 2-centrifugal wheel; 3 - Insert I; 4 - vortex wheel, 5 - insertion II; 6 - Facial Seal, 7 - Case, 8 - Shaft In the digital designation of the pump numerator fraction - feed (l / s.), Denominator - pressure (M.Vost.st.). Structurally, they are a console horizontal pump with two working wheels. The impeller of the first stage is a centrifugal, second stage - vortex. Such a combination allows us to obtain normal suction conditions with the help of the first stage, (permissible vacuum height of suction -7 m), and with the help of a second stage - high pressure. The material of the flow part of the cast iron, the vortex wheel - steel 35l. Shaft seal - end, it is possible to install the gland with a soft package. Pumps can be equipped with electric motors in an explosion-proof version. Currently, the following manufacturers of pumps and equipment manufacturing plants are operating: OJSC Livgidromash, FSUE "Turbosasos", OJSC "Bobruiskaya Machine-Building Plant", OJSC "Schelkovsky Pump Plant", CJSC "Katai Pump Plant", CJSC "Yasnogorsky Machine-building plant, "Sumy Machine-Building Plant", OJSC "Uralgidromash", JSC "Vakummash", JSC "Moldovakhidromash", ZAO "Rybnitski Pump Plant", OJSC "Gornas", OJSC "Prompribor", OJSC Kusinsky Machine-Building Plant. Literature Main literature 1. Bystritsky G.F.Onevna Energy. Tutorial: M., infra-m. 2007. 2. Zalutsky E.V. and others. Pumping stations.-Kiev. "Visitor School." 2006. 3. Modern heat power / ed. Turning A.D. / Mai. 2007. 4. Solovyov Yu.P. Accessories at electric stations. M.: Publishing house MEI. 2005. 5. Sterman L.S., Lavogin V.M., Tishin S.G. Thermal and atomic electrical stations. - M.: Publishing House MEI. 2007. 6. Thermal and nuclear power plants. / Ed. A.V. Klimenko /, T.3.MEI. 2004. 7. Heat electrical stations: Textbook for universities / ed. E.D. Burova et al. M. Mei. 2007. 8. Tiator I.N. Pumping equipment of heating systems. - M.: Publishing House MEI. 2006. additional literature 9. Budov V.M. NPP pumps. - M.: Energoatomizdat. 1986. 10. Gorshkov A.M. Pumps.- M.-L.: Mechanical Engineering. 1947. 11. Karelin V.Ya. Pumps and pumping stations. - M.: Energy. 1996. 12. Krivchenko G.I. Hydraulic machines. Turbines and pumps. M.: Energy. 1988. 13. Lomakin A.A. Centrifugal and axial pumps. - M.: Mechanical Engineering. 1976. 14. Malyyushenko V.V. Energy pumps. - M.: Energy. 1981. 15. Malyyushenko V.V., Mikhailov A.K. Pumping equipment of thermal power plants. - M.: 1975. 16. Levers V.V. and others. Pumps and pumping stations. - M.: Kolos. 1988. 17.Ctepanov A.I. Centrifugal and axial pumps. M.: Mashgiz. 1960. 18.Etellium directory. T.1., M.: Energy. 1975. 19. Cherkassky V.M. Pumps, fans, compressors. - M.: Energy. 1994. 20.chnyaev I.A. Bandal pumps. Reference manual. - M.: Mechanical Engineering. 1992. 21. Sherstyuk A.N. Pumps, fans, compressors. - M.: Higher School. 1972. 22. Engel-Kron I.V. Device and repair of equipment of turbine shops of power plants. - M.: Higher School. 1971. Pumps and compressors The Ministry of Higher and Secondary Special Education of the USSR as a tutorial for students of the oil specialties of universities The book describes the main information on the theory of pumps and compressors. Specifications are given and the basic designs of modern machines, as well as some of the features of their operation, associated with the use of pumps and compressors in the oil, gas and petrochemical industries are given. The book is a teaching manual for students of oil universities. It can be used by engineering workers engaged in the design and operation of pumps and compressors. © Subsidian Publishing House 1973 1. Berdyukv.A. and others. Construction and installation of pumping and compressor stations of the main pipelines. M., "Nedra", 1968, 283 p. With IL. 2. Bibicheva. V., Rabinovich 3. Y. Operation of equipment of the main gas pipelines. M., Gostoptekhizdat, 1963, 431 p. With IL. 3. G and l and m s n o in F. G. Fans. Atlas designs. M., "Mechanical Engineering", 1968, 186 p. With IL. 4. 3 a x a r e n to about S. E. et al. Piston compressors. M.-JI., Mashgiz, 1961, 454 p. With IL. 5. Kadyrov A. M., with a and about f and to about in V. S. Oilfield compressors. Baku, Azneftizdat, 1952, 332 p. With IL. 6. K a l and n at sh c and n M. P. Hydraulic machines and refrigeration units M.; Gosstroyisdat, 1957, 219 p. With IL. 7. Kiselev V.I. Pumps, compressors, fans. M., Metallurgizdat, 1961, 400 p. With IL. 8. Air and gas compressors. Directory-directory. M., Mashgiz, 1954, 166 p. With IL. 9. Contactor. B. Pumps and blowers. M., Metallurgizdat, 1956, 334 p. With IL. 10. PL E V A K O N. A. Basics of hydraulics and hydraulic machines. M., Rostech- Edition, 1960, 428 p. With IL. 11. Rakov A. A., Vinogradov Yu. A. Compressors. M., "Mechanical Engineering", 1965, 280 p. With IL. 12. Rice V. F. Centrifugal compressor machines. M. - Ji. "Mechanical Engineering", 1964, 336 p. With IL. 13. Seleznev K. P., P o d o b a E in Yu. S., and N and C and M about in S. A. Theory and calculation of turbo-compressors. M., "Mechanical Engineering", 1968, 406 p. With IL. 14. Stepanov A. I. Centrifugal and axial compressors, blowers and fans. M., Mashgiz, 1960, 347 p. With IL. 15. S t r a x about B and h K.I. and others. Compressor machines. MM GOSTORGIZDAT, 1961, ROOOO. With IL. 16. X L U M S K and Y V. Piston compressors. M., Mashgiz, 1962, 403 p. With IL. 17. Ch E R K A C C C I Y V V. M., R O M A N O V A T M., K A U L R R. A. Pumps, compressors, fans. M., "Energy", 1968, 304 p. With IL. Here is a small selection of technical literature dedicated to the pumping equipment, water supply and sewage in format djvu. For free download. Name: Pumps, Fans, Compressors Name: Mechanical vacuum pumps Name: Water supply. Textbook for universities. Name: Plate Pumps and Hydromotors Name: Gears pumps. The main parameters and their calculation Name: Operation of water intakes of groundwater Name: Cleaning and the use of wastewater in industrial water supply Name: Pumps and pumping stations Name: Automated systems for controlling the technological processes of feeding and distribution of water. Name: Water supply and sanitation. External networks and facilities www.agrovodcom.ru. Pump – the machine intended for transforming the mechanical drive energy into the hydraulic energy of the flow of the pumped liquid medium in order to lift it and move (Figure 2.87). Figure 2.87 - Centrifugal Console Horizontal Pump
with axial fluid entrance with internal supports
Figure 2.88 - Pump unit type to
Figure 2.89 - General view of the pumping unit (centrifugal pump, with axial hull connector, single-span with remote supports) In oil refineries, pumps are served to pump oil, petroleum products, liquefied gases, water, alkali, acids and operate in wide range of performance, pressure and temperature. Therefore, the usual requirements for pumps (reliability and durability in operation, the tightness of the compounds and the impeccable operation of the gland or ending seals), in the conditions of these enterprises, are extremely important, since malfunctions in pumps and their nodes lead to the technological regime of installations, and sometimes and to accidents. Requirements for reliability and durability of pumps increase, especially now, when the number of backup pumping equipment is sharply reduced in the projects of new technological installations. Due to the wide variety of structures, the areas of use, the properties of the pumped fluid to develop a unified classification for pumps has not yet been possible. Therefore, the classification is carried out on individual features. Moreover, in various literature, the classification of pumps is not always identical to each other. BUT) By basic parameters Includes such indicators as the nominal beneficial power of the pump, the nominal feed and pressure. Power and feed
Pumps are conventionally divided by major (Table 2.1). Table 2.1 - pump size indicators
For a developed pressure, the pumps with low (up to 10 m) differ, mean (up to 70 m) and high (more than 70 m) pressure at appropriate pressures to 0.1; 0.7 and more than 0.7 MPa. B) for its intended purpose. General purpose pumps
- Designed for pumping cold, clean, non-aggressive water or similar to it on the physico-chemical properties of liquids. Pumps are used in various sectors of the national economy. Weighing Transport Pumps
- Designed for pumping neutral or low-breeding liquids with solid particles. They are used in the mining industry, construction, utilities, etc. The group includes soil, slurry, fecal, massive and other pumps. Energy pumps
- Designed to work in the schemes of thermal nuclear power plants. These include nutritious, condensate, network and special pumps. Chemical pumps
- Designed for pumping clean and contaminated aggressive liquids in the chemical industry. Pumps for the oil and petrochemical industry
- Designed for crude oil and products of its processing in a wide range of temperatures. These are pumps for trunk petroleum products, alternate planting of oil reservoirs, gasoline, liquefied gases, etc. C) on the principle of action The feed element pumps by one sources are divided into dynamic, volumetric
and special
, in others, on dynamic and volumetric. Schematically, one of the possible classifications of pumps on the principle of action is shown in Figure 2.90. Figure 2.90 - Classification of pumps on the principle of action
In dynamic pumps, the fluid under the influence of hydrodynamic forces is moved in the chamber (open volume), which is constantly communicating with the entrance and pump output. By type of forces acting on a liquid medium, dynamic pumps are divided into bandal, friction pumps and electromagnetic
. In the same literary source, dynamic pumps are divided into lobed and vortex. Blade
They call pumps in which the fluid moves due to the energy transmitted by it when the impact blades of the impeller. Bandal pumps depending on the nature of the power interaction and the flow direction in the working wheel are divided into: centrifugal (radial and diagonal) and axial . IN centrifugal Pumps The fluid flow in the region of the blade wheel has a radial direction and moves mainly under the influence of centrifugal forces. IN axialpumps flow fluid moves through the impeller in the direction of its axis, i.e. The parallel axis of rotation and moves in the field of action of the hydrodynamic forces arising from the interaction of the stream and the blade wheel (Figure 2.91). IN pumps
friction
The liquid moves under the influence of friction forces. This group includes vortex, disc, bias, vibration, labyrinth, screw and inkjet pumps. The most common among this group of pumps are vortex Pumps. In some works, disk, scraper, vibration, labyrinth, screw and jet pumps are isolated in a separate group and refer to special pumps. IN vortex Pumps The use of centrifugal force for injection of fluid and the use of the blade wheel create the impression of a large similarity of the vortex pump with centrifugal. However, in the vortex pump, the increment of the energy of the pumped liquid occurs as a result of turbulent metabolism of the main stream at the inlet of the pump and the secondary stream in the handling wheel, i.e. When the pump is running, the fluid filling the impeller, as a result of friction carries the liquid from the suction pipe into the annular channel and moves it to the injection fitting (Figure 2.92). 1 - body; 2 - Rotor Figure 2.91 - Scheme of axial pump
1 - body; 2 - channel; 3 - impeller; 4 and 6 - holes for supplying and removing fluid; 5 - air separator Figure 2.92 - Vortex pump
IN electromagnetic pumps
The fluid moves under the action of electromagnetic forces. These pumps are designed mainly for pumping liquid metal in a magnetic field. IN volume pump
The liquid medium moves due to a periodic change in the volume of the camera occupied by it, alternately communicated with the entrance and output, i.e. The liquid in it moves by individual portions. The principle of the operation of the volume pump consists in displacement (movement) of a certain working volume of the fluid, so they are also called displacement pumps (for example, a piston pump, in which the piston gradually displaces the entire liquid concluded in the working volume of the cylinder). Volumetric pumps - self-priming, they pump low-viscosity and highly viscous liquids, pastes, resins, etc., as well as fluids with a large content of gases and cryogenic. Volumetric type pumps are usually divided into two groups - reciprocating and rotary. IN reciprocating Pumps fluid moves under the action of the piston or the diaphragm. Using valves, the cylinder is connected alternately with the supply pipe, then with the pressure pipe. IN rotary pumps One or more rotating rotors form in the cavity pump housing, which capture the pumped liquid and move it from the inlet nozzle of the pump to pressure. Rotary pumps include gears (Figure 2.93), screw, lamellar. 1 - unloading grooves; 2 - suction hole; 3 - pressure nozzle; 4 - leading gear Figure 2.93 - gear pump
The choice of materials, the design and principle of operation of pumps depend on the physical and chemical properties of pumped liquids. You can recommend subdivide pumps for pumping: D) depending on temperature Pumping fluid pumps are divided into cold
(T≤373 K) and hot
(T\u003e 373 K). The most common group of all these types of pumps is centrifugal pumps. Therefore, further focus on this group of pumps. Currently, there are a large number of pumping and compressor equipment (NGOs) at refinery and petrochemical enterprises. For example, at OJSC "Syzransky refinery" under the maintenance of Technudsor is the following supervisory equipment: compressors - 64 pcs., Pumps - 872 pcs., Vessels and devices - 1097 pcs., The total length of pipelines is 386.5 km. Such a distribution is typical for many refineries and petrochemical plants. It should be noted that from the entire fleet of pumping units, centrifugal pumps occupy a leading role. For the implementation of technological processes of oil refining, more than 2000 pumping units of various types and structures can be used, about 80% of which can be centrifugal pumps, The main group of centrifugal pumps for the oil refining industry is characterized by the following parameters: Feed up to 360 m 3 / h, pressure up to 320 m, installed power up to 500 kW. More powerful pumps (power up to 1250 kW) are rarely applied. Approximately about 50-55% of centrifugal pumps operating in the oil refining pump have a driving power not exceeding 100-110 kW. Centrifugal pumps can be used in wide ranges of temperatures and pressures. The distribution of centrifugal pumps for one of the Ufa refinery at operating temperature and pressure showed that the pumps were used from minus temperatures to the temperatures of the components of 300-400 ○ C, and about 40% of the total number of pumps is operated in this range. The pressure range in which centrifugal pumps are used is from 0.04 to 15 MPa. Such a wide distribution of centrifugal pumps is due to the number of their advantages compared to other types. A very significant advantage of centrifugal pumps are small dimensions, high speeds of rotation, with which the moving parts of the pumps work and moves the liquid. The absence in centrifugal pumps of the reciprocating movement and the inertia caused by them allows for the possibility of working with minimal sizes of foundations. In this regard, the cost of the pump itself, the premises, the initial installation, further care and repair is significantly less than for the piston pump. The next advantage of centrifugal pumps is the lack of valves and other parts that are often the cause of problems in the work of piston pumps. Also, a positive factor is the presence of a rotational movement of the shaft alone, moreover, with a large number of revolutions without reciprocating movements of any parts, which greatly simplifies the connection with the engine, eliminates complex transfer mechanisms, especially when the centrifugal pump is directly connected to the engine on the same shaft. Types of centrifugal pumps a lot. Despite the principal similarity of the structure, centrifugal pumps of different types have a number of features that allow them to exploit them in various conditions. Centrifugal pumps can be attributed to many of the indicated signs. In addition, they can be divided (as well as pumps of other types) according to constructive features. According to constructive signs Centrifugal pumps are divided into several groups (Figure 2.94). Figure 2.94 - Classification of centrifugal pumps
according to constructive signs
Figure 2.95 - Centrifugal Pump Console Horizontal with Inner Opports
Figure 2.96 - centrifugal pump vertical type
By the flow of fluid to the wheel
- from one-sided I.bilateral suction (Figure 2.97). Under the conditions of chemical production, second type pumps are used very rarely due to their constructive complexity (significant length, the presence of two salts, etc.). The advantages of pumps with bilateral suction do not reach these flaws. 1 - Single Suction Wheels 2 - Two-sided suction wheel Multistage pumps are used for water supply, hydromechanization, pumping of mine waters, boiler nutrition and in other areas of technology where large pressure are required. In these pumps, water passes sequentially through several working wheels mounted in one case. Table 2.2 shows the most characteristic design features for dynamic Pumps - blade (centrifugal and axial) and vortex, as the most common. The pumping industry of our country produces hundreds of a wide variety of centrifugal pumps of various purposes. In order to quickly and properly select a centrifugal pump for specific production needs, several systems of their designation are developed. Marking pumps normal
Rows are performed in shape: the first digit is the diameter of the suction nozzle in mm, reduced 25 times and rounded; Next, follow letters that are denoted by: N - Oil, G - hot; D - the first wheel of the two-way entrance; In - vertical; K - Console; Ke - console, mounted in one block with an electric motor; M - multistage. The second digit is the speed ratio or specific speed, reduced 10 times and rounded. The third digit is the number of steps; Letters at the end of the marking: K is acidic; C - for liquefied gases. Examples of designation and marking of pumps: 8ng-10x2 is a centrifugal pump, the diameter of the suction nozzle 200 mm, oil, hot (for fluid with a temperature of 220-400 ° C), the coefficient of speed 100, the number of steps 2. 8ngk-10x1 is a centrifugal pump, the diameter of the suction nozzle 200 mm, oil, hot, console, the coefficient of speed 100, the number of steps 1. 14ngd-10x3 is a centrifugal pump, the diameter of the suction nozzle 350 mm, oil, hot, the first wheel of the two-way entrance. 8nd-10x5 is a centrifugal pump, the diameter of the suction pipe 200 mm, the oil (temperature 3 / h, and the nominal pressure, M of the liquid column. Examples of symbols: The console pump with a supply of 125 m 3 / h and the pressure of 30 m is denoted as follows: to 125 - 30 or to 125/30, and the horizontal fecal pump with the same indicators - 125 - 30 or FG 125/30. Pump brand to 20 / 18-5-y3: 20 - feed, m3 / h; 18 - pressure, m. Multistage sectional pumps have the designations of the CNS. For example, the brand CNS 180-212: CNS is a centrifugal sectional pump; supply q \u003d 180 m 3 / h; pressure H \u003d 212 m. Pump centrifugal K65-50-160 / 2 The symbol of the pump means: K is a console; 65-50 - feeding in m 3 / h when turning the impeller; 160 - pressure in m; 2 - Modernization index. The following labeling is also applied: Mail pump 65-50-160A / 2-5-U3 brand: Km - Pump Horizontal Console Monoblock; 65 - diameter of the inlet nozzle, mm; 50 - the diameter of the outlet nozzle, mm; 160 - nominal diameter of the impeller, mm; a - the conditional designation of the impeller with a sharpening, ensuring the operation of the unit in the middle part of the "Q-H" field; 2 - Conditional designation of the number of revolutions of the electric motor: 5 - single mechanical seal; Y3 - climatic execution and category of placement during operation according to GOST 15150-69; P - fireplace with a soft stuffing gland. Pump brand KM 50-32-200: 50 - diameter of the inlet nozzle, mm; 32 - the diameter of the outlet, mm; 200 - nominal diameter of the impeller, mm. To date, the following alphabetic designation of pump brands common
Appointments: K - single-stage cantilever pump; In - pump, single-stage, vertical, console; D - single-stage pump with a two-way imaging wheels; CNS - Pump section multi-stage; CN - multistage pump; VK - Vortex Pump, Console; CV - centrifugal-vortex pump; SVN - pump, self-priming vortex. Schematically, the centrifugal pump is shown in Figure 2.98. In the cast-iron spiral case 1, the shaft 8 rotates in motion from the electric motor, the steam turbine, the internal combustion engine (directly or through the clinorem). The shaft is fixed with the impeller 3 with blades, the space between which the channels for the passage of the liquid are formed. 1 - body; 2 - suction fitting; 3 - impeller; 4 - discharge fitting; 5 - catch; 6 - check valve; 7 - manometer; 8 - shaft; 9 - vacuummeter; 10 - receiving valve with grid Figure 2.98 - Centrifugal pump
In the injection pipeline installed 5, which serves for overlapping the pipeline and control the performance of the pump. It is located above it is the return valve 6. With a sudden stopping of the pump, it prevents the reverse current of the fluid and thereby protects the pump from the hydraulic impact, which can cause the pump breakage. At the end of the suction pipe, immersed in the liquid, a receiving valve 10 was installed, which prevents the flow of fluid from the suction pipe and the pump when the latter is stopped. If the internal space of the pump and its suction piping is filled with liquid, then when rotating the impeller's impeller, the fluid is carried away, and the centrifugal force arising from this threads it into the spiral channel (the so-called "snail") of the housing. Moving through the channel, the liquid enters the discharge fitting and from it to the injection pipeline. As a result of the exit of the transported fluid into the discharge pipe in the suction cavity, a vacuum is created, and the liquid from a empty tank or the device begins to rise in the suction tube into the pump. Thus, the process of uniform pumping of the fluid is established. The pressure (pressure), developed by the centrifugal force, in the active pump is directly proportional to the square of the speed of the impeller. Schematically, the centrifugal pump consists of the impeller 4 (Figure 2.99), equipped with blades and installed on the shaft 1 in the spiral case 5. The diagram of the fluid flow in the pump housing is shown in Figure 2.100. 1 - shaft; 2 - discharge nozzle; 3 - blade; 4 - impeller; 5 - housing Despite the large variety of the designs of centrifugal pumps (Figure 2.101) consist of the following main nodes and parts: housing, rotor with an impeller, bearings, end seals shaft, working wheels, connecting couplings. Figure 2.101 - centrifugal single-span horizontal multistage pump with axial connector and lateral fluid inlet with a spiral case Mainly applied spiral and sectional Cases. Spiral enclosures are used for single-stage (with one impeller) and multistage pumps. The housing of the spiral type pump is a complex part consisting of the shells of various shapes, a number of differently loaded and fixed plates of arbitrary shape, etc. Such a housing for the console pump can be made either as a separate casting, or with a lid and nozzle (Figure 2.102). Pumps with passage shaft, i.e. One-break, when the impeller or wheels are located between the bearings (supports) have a spiral body, consisting of two parts: the lower part and the covers connected by the studs (Figures 2.103). Figure 2.102 - Spiral Console Pump Case
Figure 2.103 - Spiral Case of the One-Run Pump
Spiral enclosures of multistage pumps (see Figure 2.101, 2.103, 2.104) have many general solutions with single-stage pumping housings. They represent the castings of a complex shape. Steps are connected by translated channels made in casting or with the help of translated pipes. The spiral housings of large and medium pumps have a horizontal connector in the plane passing through the pump axis, which makes it possible to disassemble, collect and control the state of the internal water supply channels without dismantling pipelines at the site of operation. Figure 2.104 - Horizontal centrifugal connector
In the presence of the connector of the input and outlet nozzles of the pump are molded at the bottom of the housing. The support paws and brackets for fastening the bearings housing are also poured. Most often no pipes are horizontally and sent to the opposite sides. At the bottom of the case, the holes are provided for the complete emptying of the pump. In the case cover, there must be similar holes for the release of air. When pumping, these holes are closed with traffic jams. For transportation of pumps in the case, special tides are made in the form of hooks, lylish in the rigids or bolt bolts. The sectional case represents a set of sections having connectors in planes, perpendicular to the axis of the pump, input and output covers interconnected by tie studs. The input and output covers are the basic parts of the pump. In the covers are made according to the input and outlet nozzles. The section of the section pump is shown in Figure 2.105. Figure 2.105 - Section of the Section Pump
The rotor (Figure 2.106) of the blade pump is a separate assembly unit, which largely determines the efficiency, reliability and durability of the pump. Figure 2.106 - Multistage Pump Rotor
The basic part of the rotor is usually a two-pressure shaft on which operating wheels, protective bushings, coupling and other small parts mounted on the shaft are installed. With a console design of the rotor (Figure 2.107, a), the impeller is placed at the end of the shaft and fix on it in the axial direction with a nut, which is simultaneously a fairing. In single-stage pumps with passage shaft (Figure 2.107, b), the impeller is usually set at an equal distance from the supports. In multistage pumps (Figure 2.107, B, d), the location of the wheel set depends on the design of the pump. The working wheels of the steps rest in the shaft bin and through the sleeve round nuts are fixed in the axial direction. In the pumps pumping hot fluids, between a set of working wheels and a thrust sleeve provide a gap 0.5-1.0 mm to compensate for thermal expansions of rotor parts. a - rotor of the console pump; B - rotor of a single-year single-stage pump; b, M - Rotors of multistage single-spare pumps Figure 2.107 - Rotors of pumps
At the drive end of the shaft, which has a cylindrical or conical shape, is installed by a half, which can be fixed in the axial direction with a circular nut. Most rotor parts are planted on the shaft on the knaps. Details installed without a sponge compound must be securely fixed from turning. Depending on the design circuit of the pump, the rotors are unilateral (the input funnel of the working wheels is directed in one direction) and the symmetric arrangement of the working wheels. In the latter case, the working wheels are pairwise spread into entry funnels in opposite sides. In the working wheel, there is a transformation of the mechanical drive energy into the hydraulic energy of the pumped fluid. Wheels are performed by radial, diagonal and axial types. The impeller of the closed type (Figure 2.108, A, 2.109) consists of the leading 3 and driven 1 discs with the blades located between them 2. The semi-open-type impeding wheel (Figure 2.108, b) does not have a covering disk, and the blades are made at the same place with the main (leading ) Disk. Open-type impeller (Figure 2.108, c) has no discs, and the blades are attached to the sleeve, similar to the working wheel of the axial pump. 1 - slave disk; 2 - blade; 3 - lead disk Figure 2.108 - Schemes of working wheels of dynamic pumps
Figure 2.109 - Wheels of closed type
The clearance between the wheel and the lid should be minimal, but providing free (without friction) wheel rotation. It is usually chosen in the range of 0.4-0.6 mm. With an increase in the gap increases the amount of fluid flowing from the pressure cavity into the suction under the influence of the pressure difference. The front disk of the wheel has a sharpened cylindrical surface, which it enters into the pump housing cover. In the lid, in turn, the sealing ring is pressed. The main purpose of the sleeves is to protect the shaft from corrosion, erosion and wear. There is a wide variety of bushings for appointment and constructive features. The most responsible shaft sleeves in the shaft seal zone are most responsible. Depending on the type of seal, the imposition of the sleeves is changing. In the pumps, three types of connecting couplings were most common: elastic, elastically finger and gear. All centrifugal pumps stipulated by the standard are designed to drive from electric motors with a direct connection with an elastic coupling (Figure 2.110). However, the type K pumps can be supplied with a pulley for belt transmission. A - elastic membranes of stainless steel; B - protective sleeves, overload protection; C - anti-corrosion treatment; D - membrane assemblies to relieve mounting; E - Tight landing bolts to save balancing properties Figure 2.110 - Elastic Plate Couplings for the joint of the shafts of the company "John Crane" (England
) Thanks to the use of elastic elements of new designs, the couplings are allowed compared to the well-known standard elements of the shafts axes, radial and axial displacements. The coup design allows you to easily install them and reduce installation time. End shaft seals.
To compact the pump shaft in the locations of it from the housing, the end seals are provided, which: End seals are one of the most important nodes of the pump that characterize the reliability of its operation. With all the variety of structural designs, end seals can be divided into three groups: Contact seals
divided by sloves, end and seals with floating rings. Currently received the greatest distribution, it provides almost complete tightness. Torch seals have numerous design varieties. The end seals are single (Figure 2.110, 2.111), double (Figure 2.112), single-stage, two-stage, etc. 1 - stationary pair of friction; 2 - rotating steam of friction; 3 - clamp; 4 - Ring; 5 - spring; 8 - Purpose Ring; 7, 9 - V-ring; 10 - Purpose Ring; 6, 11, 12 - Screw Figure 2.110 - Scheme of Single Face Seal
Figure 2.112 - Dual Fur Tandem Tone Seal Diagram
The element movable in the axial direction is centered in the housing along the rubber ring of the circular section, so that it can move along the surface of the rigid element. Wheel seals.
The seal of the impeller of the centrifugal pump serves to reduce the volumetric losses and an increase in the efficiency by reducing the water leaks from the pressure section into the suction through the gap between the rotor and the stator. Contact slotted seals usually apply as a seal of the impeller. Their sealing effect is based on the use of hydraulic resistance of annular chokes with a small radial gap. The radial gap takes the minimum subject to ensure reliable assembly and work without the metal contact of the rotating and fixed elements of the pump. Figure 2.113 shows the schemes of slit seals used in centrifugal pumps. The slotted seal consists of a sealing and protective rings fixed accordingly in the pump housing and on the handling wheel. Rings are pressed or fasten with screws in such a way that a gap with a gap is formed between their sealing surfaces. a - direct; b - angular; 1 - pump housing; 2 - Sealing ring; 3 - impeller; 4 - Protective Ring Figure 2.113 - Slitteen of the impeller
In the prevailing majority of pumps apply remote bearings. All bearings are divided into two groups: radial - perceive radial efforts, and stubborn- perceive axial efforts acting on the rotor. For small and medium pumps, ball-and roller bearings are used as radial supports (Figure 2.114). The main advantages are minimal friction losses, small sizes, easy shift and the ability of many rolling bearings to perceive not only radial, but also axial efforts. Figure 2.114 - Ball Bearing
For large circle speeds, the performance of ball bearings is sharply reduced. In addition, when the bearing is destroyed, the rotor is destroyed. Therefore, for responsible pumps, sliding bearings are often used as radial supports, which, with proper installation and operation, have almost unlimited operation time. In most structures, many stepped pumps for the perception of unbalanced axial efforts are used by two radial-resistant ball bearings that perceive the effort in two directions. The thrust bearing is usually located on the side of the free end of the pump shaft in a common case with a radial bearing. Currently, work continues on the development of new pump designs. Pumps - Machines for creating a pressure flow of a liquid medium. When developing hydraulic systems and networks, the correct choice and use of pumps allows you to obtain the setting parameters of the fluid movement in hydraulic systems. At the same time, the designer needs to know constructive features of pumps, their properties and characteristics. In this section you can free and without registration download books on centrifugal, blade, gear pumps and fans. Ministry of Education and Science of the Russian Federation Federal State Budgetary Educational Institution of Higher Professional Education Yaroslavl State Technical University Department "Processes and Chemical Technologies" Calculation of pumping installation Tutorial Compilers: Cand. tehn Sciences, Associate Professor V. K. Leontiev, Assistant M. A. Barasheva Yaroslavl 2013. ANNOTATION A brief theoretical information on the calculation of simple and complex pipelines, the calculation of the basic parameters of the pumps. Examples of calculations of pipelines and selection of pumps are given. Multivariate tasks have been developed for performing calculation works. Particular attention was paid to the designs of dynamic pumps and volumetric pumps. The training manual is intended for students who perform settlement work and coursework on the courses "Hydraulics", "Fluid and Gas Mechanics" and "Processes and Chemical Technologies". Introduction 1. Hydraulic calculation of pipelines 1.3. Complex pipelines 1.3.1. Serial connection of pipelines 1.3.2. Parallel connection of pipelines 1.3.3. Complex branched pipeline 2. Calculation of pumping installation 2.1. Pump operation parameters 2.1.1. Pump installation pressure definition 2.1.2. Measurement of the pump setting using devices 2.1.3. Determination of useful power, power on the shaft, the efficiency of the pumping unit 3. Classification of pumps 3.1. Dynamic pumps 3.1.1. Centrifugal pumps 3.1.2. Axial (propeller) pumps 3.1.3. Vortex pumps 3.1.4. Inkjet pumps 3.1.5 Air (Gas) Lifts 3.2 Volumetric pumps 3.2.1 Piston pumps 3.2.2 Gears 3.2.3 Screw pumps 3.2.4 Plastic Pumps 3.2.5 Assembly 3.3 Advantages and disadvantages of pumps of various types 4. Task for the calculation of the pumping installation Exercise 1 4.1. Example of calculating the simple pipeline Task 2. 4.2. An example of calculating the complex pipeline Task 3. 4.3. Example of calculating the pumping installation Task 4. 4.4. An example of calculating and selecting a fluid pump in Bibliographic list Appendix A. Appendix B. Appendix B. Introduction In chemical production, most technological processes are carried out with the participation of liquid substances. It is a raw material that is served from a warehouse for a technological installation, these are intermediate products moved between devices, installations, plant shops, these are the final products delivered in the containers of the finished product warehouse. On all movements of liquids, both horizontally and vertically, it is necessary to spend energy. The most common source of fluid flow is the pump. In other words, the pump creates a pressure fluid pressure. The pump is an integral part of the pumping unit, which includes suction and discharge (pressure) pipelines; Original and receiving tanks (or technological devices); regulating pipe fittings (cranes, valves, valves); Measuring instruments. The correctly selected pump should provide a given fluid consumption in this pumping unit, while working in economy mode, i.e. In the field of maximum efficiency. When choosing a pump, it is necessary to take into account the corrosion and other properties of the pumped liquid. 1. Hydraulic calculation of pipelines 1.1. Classification of pipelines The role of pipeline systems in the farm of any country, a separate corporation or simply an individual economy is difficult to overestimate. Pipeline systems are currently the most efficient, reliable and environmentally friendly transport for liquid and gaseous products. Over time, their role in the development of scientific and technological progress increases. Only with the help of pipelines it is achieved the possibility of combining countries of hydrocarbon raw materials with consumers. A large proportion in the transfer of liquids and gases by law belongs to systems of gas pipelines and oil pipelines. In almost every machine and the mechanism, a significant role belongs to pipelines. In its purpose, pipelines are made to distinguish with the type of products transported on them: - gas pipelines; - oil pipelines; - water pipes; - air bodies; –
products. By type of movement on them liquids, pipelines can be divided into two categories: –
pressure pipelines; –
performance (self-reading) pipelines. In the pressure pipeline, the internal absolute pressure of the transported medium is more than 0.1 MPa. Performance pipelines work without overpressure, the movement of the medium in them is provided by a natural geodesic slope. The magnitude of the loss of pressure on local resistance pipelines are divided into short and long. IN short pipelines for the loss of pressure on local resistance exceed either equal to 10% of the pressure loss in length. When calculating such pipelines, it is necessarily taken into account the loss of pressure on local resistance. These include, for example, oil-based volume transmissions. Long pipelines include pipelines in which local losses are less than 10% of the pressure loss in length. Their calculation is carried out without taking into account losses for local resistance. Such pipelines include, for example, trunk waterways, oil pipelines. According to the scheme of pipeline pipelines, they can also be divided into simple and complex. Simple pipelines are consistently connected pipelines of one or various sections that have no branches. Sophisticated pipelines include pipe systems with one or more branches, parallel branches, etc. By changing the consumption of the transported environment, pipelines are: - transit; –
with track expenses. In transit liquid selection pipelines, as it is moved, the flow consumption remains constant, in the pipelines with the way consumption, the flow rate changes along the length of the pipeline. Also, pipelines can be divided by the type of section: on the circular and non-round pipelines (rectangular, square and other profiles). Pipelines can be divided into material from which they are made: steel pipelines, concrete, plastic, etc. 1.2. Simple pipeline constant section The main element of any pipeline system, no matter how difficult it is, is a simple pipeline. The simple pipeline, according to the classical definition, is the pipeline collected from the pipes of the same diameter and the quality of its inner walls, in which the transit flow of the fluid is moving, and on which there are no local hydraulic resistances. Consider a simple pipeline of a constant cross section having a total length L and diameter D, as well as a number of local resistances (valve, filter, check valve). Fig. 1.1 Simple Pipeline Scheme The size of the pipeline cross-section (diameter or size of the hydraulic radius), as well as its length (length) of the pipeline (L, L) are the main geometric characteristics of the pipeline. The main technological characteristics of the pipeline are the flow rate of the liquid in the pipeline q and pressure H (on the head facilities of the pipeline, i.e. at its beginning). Most of the other characteristics of the simple pipeline are, despite their importance, derived characteristics. Since in a simple pipeline flow rate transit (the same at the beginning and end of the pipeline), then the average fluid movement in the pipeline is constant ν \u003d Cons't. We write the Bernoulli equation for sections 1-1 and 2-2. h p where Z 1, Z 2 is the distance from the comparison plane to the centers of severity of the sedicated sections - geometric pressure, m; P1, P2. - pressure in the center of severity of the selected sections, PA; - flow density, kg / m3; g - acceleration of free fall, m / s2; - average flow rate in the corresponding sections h P - pressure loss in the pipeline, m; g - piezometric pressure, m; 2 g - high-speed pressure, m. Since the cross-section of the pipeline is constantly, then the speed of the flow is the same along the entire length of the pipeline, and accordingly the high-speed pressure in the sections 1-1 and 2-2 are equal. Then the Bernoulli equation takes the following form: h p. The piping loss in the pipeline is made up of friction losses and local resistance, according to the principle of addition of pressure loss in the pipeline can be defined as: where is the friction coefficient; L is the length of the pipeline, m; d - the inner diameter of the pipeline, m: - The sum of the coefficients of local resistances. The size of the pressure loss is directly related to the flow rate of the liquid in the pipeline. Thus, the piping loss in the pipeline can be determined 2 g S. The dependence of the total pressure loss in the pipeline from the volume flow of fluid H n f (q) is called the characteristics of the pipeline. In the case of a turbulent motion mode, the allowing quadratic law of resistance (\u003d Cons't) can be considered a constant value of the following expression: Fig. 1.2 Characteristics of the pipeline 1 is the characteristics of the pipeline during laminar mode of fluid motion; 2 - Pipeline characteristics in turbulent motion mode The needed pressure is a piezometric pressure at the beginning of the pipeline, according to the Bernoulli equation: H Potter z 2 z 1 h p. Thus, the need for pressure is spent on the rise of fluid to the height Z Z 2 Z 1, overcoming the pressure at the end of the pipeline and to overcome the resistance of the pipeline. The sum of the first two terms in the formula (1.9) is permanent, it is called static pressure: The dependence of the required pipeline pressure from the volume flow of fluid H Potch F (Q) is called network Characteristic. With a laminar flow of a curve of the need for a straight line, with turbulent has 1.3.
Complex pipelines TO complex pipelines should include those pipelines that are not suitable for the category of simple, i.e. The complex pipelines include: pipelines collected from pipes of different diameters (serial connection of pipelines), pipelines having branching: parallel connection of pipelines, pipeline network, pipelines from continuous distribution of fluid. 1.3.1. Serial connection of pipelines With a sequential connection of pipelines, the end of the previous simple pipeline is at the same time the next simple pipeline. Consider several pipes of different lengths, different diameters and containing different local resistances, which are connected in series (Figure 1.4). Fig. 1.4 Scheme of the serial pipeline
Nutritional pumping problems that can lead to emergency stopping boiler, their causes and elimination methods are given in passports and technical descriptions of pumps.
Types and types of nutrient centrifugal pumps
Technical library
Books about pumps, pumping equipment, water supply and sewage
V.M. Cherkasy
Edition:Energoatomizdat, 1983
The book is given classification, theory, characteristics and methods for regulating pumps used in the energy and other industries. The second publication is complemented by information about modern pumps. Recommended for students of universities of thermal power specialties.
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E.S. Frolov, I.V. Avtonovova, V.I. Vasilyev et al.
Edition:"Mechanical Engineering", 1989
The book describes the theory, methods for calculating and designing low, medium, high and ultra-high vacuum pumps. Workflows and types of vacuum pumps of various purposes are described, recommendations on design and specifications are given. Examples of calculation for basic types of pumps are given. The book is designed for engineering and technical workers involved in the development and operation of vacuum pump in various sectors of the national economy.
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N.N. Abramov
Edition:"Stroyzdat", 1974
The textbook provides basic information about water supply systems, appointment, working conditions, the design of the main water supply and pumps. The features of industrial and agricultural water supply systems are considered. The textbook is intended for students of universities, students in the specialty "Water supply and sewage".
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OF. Zaichenko and L.M. Mouse
Edition: "Mechanical Engineering", 1970
The book contains the basics of the theory and calculation, an overview of modern designs, as well as a methodology for testing and guidelines for the use, installation and operation of plate pumps and hydraulic motors widely used in machines and other machines. The book is designed for designers, research workers and engineers engaged in the design, manufacturing and operation of hydraulic drives and pumps.
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EAT. Yudin
Edition: "Mechanical Engineering", 1964
The book discusses the basic methods of the hydraulic and strength calculation of the gear pump, the theory of the hydraulic engine and the theory of the pump with non-circular wheels. Additionally, the calculations of aviation pumps are given. The book is designed for engineering and technical workers engaged in the development, production and operation of gear pumps.
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SURENYANTS S.Ya. Ivanov A.P.
Edition: "Stroyzdat", 1989
The book discusses the basic methods of reliable operation of water wells, the main methods of their repair and prevention. Attention is paid to the selection and features of the operation of submersible pumps for wells and methods for increasing water lifting without increasing the power of pumps. For technical specialists engaged in operation and adjusting water lifting systems.
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Khanovsky A. M., Klimenko N. A, and others.
Edition: "Energy", 1970
The book sets out the main methods of using wastewater for industrial water supply. Ways are described, removal of low-dispersed, colloid and semi-slip impurities from industrial wastewater. The technological schemes for the preparation of wastewater for use in industry are shown.
More \u003e\u003e\u003e
Yakobchik P.P.
Edition: "SPB: PGUPS", 1997
The study manual produces the parameters and characteristics of centrifugal pumps and the mode of operation of the pumping unit. The method of calculating the parameters of parallel and consistent operation of centrifugal pumps is considered. Ways to regulate the operation of centrifugal pumps are described. The appendix has summary characteristics of centrifugal and well pumps.
More \u003e\u003e\u003e
Egilsky I. S.
Edition: "L.: Stroyzdat, Leningr. Deposit, 1988 "
The book is aimed at a generalization of the existing domestic and foreign experience of creating an AESUP water supply and consideration of the main aspects of the design of these systems, the methodology for optimal management of the facilities of the supply and distribution of water, as well as issues of preparation for the implementation of ACS and the organization of these works.
More \u003e\u003e\u003e
Repin B. N., Zaporozhets S. S., Yerezov V. N., Tregubenko N. S., Mykalkin S. M.
Edition: "M.: Higher. Shk., 1995 "
When drawing up a reference, the authors proceeded from the fact that the book should contain basic materials on the calculation, design, design of networks and structures, optimizing external water supply and drainage systems, excluding the need to provide additional reference and regulatory literature.
More \u003e\u003e\u003etutorial. Equipment equipment refinery. I. R. Kuzeev, R. B. Tukayev
2.4 Centrifugal pumps
2.4.1. Common Pumps
Pump and drive motor (Figure 2.88), interconnected, measuring instruments and automatic control equipment in aggregate are pump aggregate. Pump unit and components with supplying and pressure pipelines and reinforcement is called pump installation (Figure 2.89). 
Pumps are one of the most complex types of equipment for refinery for repair and operation. It is known that the normal, trouble-free operation of any equipment in optimal modes largely depends not only on the right choice and ensure the main design solutions in the design and manufacture of machines and devices, but also on the conditions and fulfillment of the rules of their operation.2.4.2 Classification of pumps
Dynamic pumps, their classification
D) by the nature of the pumped liquid.2.4.3 Centrifugal pumps
2.4.3.1 Classification and marking of centrifugal pumps
2.4.3.2 Marking of centrifugal pumps
2.4.3.3 Principle of operation and the device of centrifugal pumps
In the case there are two fittings - 2 and 4. One of them is located along the horizontal axis of the case (its axis lies on the continuation of the axis of the shaft), and the other - regarding the spiral of the housing, at the place of its largest removal from the center. The first fitting is used to enter the liquid into the pump (the suction pipe is attached to it), the second injection.
The main elements of centrifugal pumps.
. 
The presence of the plane of the connector and the location of the input and outlet nozzles at the bottom of the housing creates certain convenience for disassembling and assembling the pump. Spiral type pump housings can be performed with a different arrangement of the input and outlet nozzles.
Rotor pump.
Protective bushings are either screwed onto the shaft, or on the axial direction of round nuts.
a, b, c - centrifugal (a - closed type; b - semi-open type; in - open type); g - vortex pump; d - axial pump;
The number of blades is usually from six to eight, but for pumps intended for pumping contaminated liquids, the number is reduced to two or four. This increases the cross-section of the channels for the passage of suspended particles. The shape and dimensions of the running part of the wheel are determined by the calculation. At the same time, it takes into account its mechanical strength and manufacturability of manufacturing.
The seal is carried out between non-rotating 1 and rotating 2 parts, which pressed one to another spring 3 (Sylphon 4). The rotating ring is fixed on the pump shaft, and not rotating - can move in the axial direction. There are other structural versions of fastening the rings on the shaft. Fixed sealing one relative to other parts is carried out by rings of rubber or plastics.
The material of sealing and protective rings should have good wear resistance, erosion and corrosive resistance, as well as resistance to blowing with a possible contact of rotating and fixed surfaces or ingress of metal inclusion.
Bibliographic list
Name:Pumps, fans, compressors: Tutorial for the thermal power specialties of universities.
Cherkasy V. M.
Description:Classifications, the formations of theory, characteristics, methods of regulation, designs and issues of operation of machinery for supplying liquids and gases used in energy and other industries are considered.
The year of publishing:1984
Views:36579
| Downloads:6834
Name:Gear pumps for metal cutting machines.
Rybkyn E.A., Usov A. A.
Description:The book contains an analysis of theoretical and experimental studies of methods for calculating and constructing gear hydraulic pumps used in hydrainized metal-cutting machines.
The year of publishing:1960
Views:35392
| Downloads:893
Name:Pumps, fans and compressors. Acquisition allowance for themp.
Sherstyuk A.N.
Description:The book outlines the basics of the theory, calculation and operation of blade machines - pumps, fans and compressors.
The year of publishing:1972
