What are industrial pumps? What types of pumps are there? Varieties of centrifugal pumps

The pump is hydraulic device, which ensures the absorption of water, its injection and movement. In their work, they use the principle of transferring liquid kinetic and potential energy. There are several types of pumps, and the division occurs based on their technical parameters. The main differences between different types of water pumps are different efficiency, power, performance, head and pressure of the outlet stream.

Currently, there are more than three thousand types of pumps. They differ in structure and purpose, and are also suitable different areas use. All this diversity can be divided into two large groups: dynamic and positive displacement pumps.

Positive displacement pumps- these are devices in which the substance moves due to the constant change in the volume of the chamber, while it is alternately combined with the inlet and outlet. They, in turn, can be divided into:

• membrane;
• rotary;
• piston.

Dynamic- these are models in which water moves along with the chamber due to hydrodynamic forces, while there is a constant communication with the inlet and outlet of the pump. Dynamic pumps are jet and vane, while the latter, in turn, are divided into centrifugal, axial and vortex.

Below, all these types of pumps, as well as their classification, will be discussed in more detail.

Rotary devices

An overview of water pumps is opened by rotary devices. Their fundamental difference is no valve. In other words, a rotary water pump moves water by pushing it out. This process is carried out by a special working element - the rotor. This is implemented as follows: water enters the working chamber. The movement of the rotor along the inner walls of the working chamber forms a change in the volume of the enclosed space, and the water is pushed out according to the laws of physics.

Advantages of rotary pumps:

• high efficiency;
• self-suction of water;
• the possibility of reverse water supply;
• pumping substances of any viscosity and temperature;
• low noise level;
• no vibration.

Of the minuses, it is worth noting that the purity of the pumped liquids (without solid inclusions) must be ensured. Besides, complex structure requires costly repairs.

Due to the ability to work with aggressive and viscous substances, rotary pumps are used in the chemical, oil, food, and marine industries. A subspecies of rotary pumps - screw - is actively used in oil production. Another area of ​​application is public utilities, where they maintain pressure in the heating system, while the pump does not need lubrication and cooling.

piston models

Piston pump design based on water displacement mechanically. This is one of the oldest types of water pumps, but in modern form its device is much more complicated than before. In particular, these pumps have an ergonomic and durable housing, a developed base of its constituent elements, as well as flexible options for connecting to a water supply system. In this regard, they are widely distributed, both in industry and in everyday life.

The pump is a metal hollow cylinder, which, in fact, is a housing - it carries out the movement of fluid. Physical impact on her plunger type piston, whose work may resemble Hydraulic Press. The operation of this device is based on reciprocating movements. When moving up (translational movement), a rarefaction of air is created in the chamber, which ensures the absorption of water. Water enters the chamber through the inlet with a valve, which at this moment opens the hole. During the return movement, this valve returns to its place, and the outlet flap opens. In this case, the piston squeezes out the water. The most common syringe works on almost the same principle.

There is one drawback in such work - the liquid flows unevenly. To eliminate this phenomenon, several pistons are used at once, which move at regular intervals, which ensures a smooth flow.

Exist double acting piston pumps. Here, the valves are located on both sides, and the water passes through the entire cylinder several times, that is, the piston, when moving, distills the water inside the working space and pushes some of it out of the pump. Due to this, it was possible to achieve a decrease in pulsation in the pipeline. The double type design has a minus - a more complex system, which makes it less reliable.

The main advantage of piston pumps is simplicity and strength, the main disadvantage is low productivity. In general, this type of pump can be made more efficient, but this does not make sense, since other types of pumps for pumping water can provide more power at a lower cost.

The scope of such pumping equipment wide enough. They allow you to work not only with water, but also with aggressive chemical environments, as well as explosive mixtures. Due to the fact that such devices cannot pump large volumes of liquid, they are not used for major tasks. However, such pumps are often found in chemical industry. They can also be used to provide an autonomous water supply system for the home or for irrigation. Another place where such devices have proven themselves successfully is the food industry. This is due to the fact that piston models are sensitive to the substances passed through them.

Membrane devices

The diaphragm pump is a relatively new type of equipment for pumping liquids and other substances. This type of equipment is capable of work with a gaseous medium and does this through a special membrane or diaphragm. It performs reciprocating movements and changes the volume of the working chamber with a given cyclicity.

The design of the device includes:

• membrane;
• working chamber;
• rod for connecting the diaphragm with the drive shaft;
• crank mechanism;
• valves to protect against the flow of substances back;
• inlet and outlet pipe.

Such pumps may have one or two working chambers. Devices with one camera are more common, those with two are used in places where higher performance is required.

The work is carried out as follows: when starting, the rod bends the membrane, which increases the volume of the chamber and creates a vacuum effect in it. This phenomenon ensures the suction of the pumped medium. After filling the chamber, the rod returns the membrane to its place, the volume decreases sharply, and the substance is pushed out through the outlet pipe. At the same time, in order to prevent liquid or gas from getting back at the moment of return movement, the inlet is automatically blocked by a special valve.

Exist models with two valves located parallel to each other. Here the process is carried out in a similar way, only there are two working chambers, and with each movement, water leaves one and enters the other. Such devices are considered more efficient.

Benefits of diaphragm pumps:

• can work with any environment;
• small size;
• quiet work;
• lack of vibration;
• simplicity and reliability of the design;
• efficiency in energy consumption;
• maintaining high purity of the pumped substance;
• low price;
• long service life;
• do not require special frequent care, they do not need lubrication;
• a person without special education can replace damaged parts;
• have high versatility.

With such an abundance of pluses, there were no significant minuses.

The diaphragm pump is widely used in medicine and pharmaceuticals, in farms (in milking machines). They are used for food production, in the nuclear field. With their help, dosing pumps are made for use in the production of varnishes and paints, they are used in the printing industry and in various places where there is a need to work with poisonous and hazardous substances. It is safe to work with the latter, since diaphragm pumps have high tightness.

jet pumps

Inkjet models are the simplest of all possible devices. They were created back in the 19th century, then they were used to pump water or air from medical test tubes, later they began to be used in mines. At present, the scope of application is even wider.

The design of the jet pump is very simple, thanks to which they practically do not require any maintenance. It consists of four parts: suction chamber, nozzle, diffuser and mixing tank. The entire operation of the device is based on the transfer of kinetic energy, while no mechanical force is used here. The jet pump has a vacuum chamber into which water is sucked. Then it moves along a special pipe, at the end of which there is a nozzle. By reducing the diameter, the flow rate increases, it enters the diffuser, and from it into the mixing chamber. Here, the water is mixed with the functional fluid, due to which the speed is reduced, but the pressure is maintained.

Jet pumps come in several types: ejector, injector, elevator.

1. ejector only transfers matter. Works with water.
2. Principle of operation injection pump- substance injection. Used to pump out steam.
3. elevator is used to lower the temperature of the carrier, which is achieved by mixing with a functional fluid.

Thus, jet pumps are used to work with water, steam or gas. They can also act to mix different substances or to lift liquids (airlift function).

This type of pump is common in various industries. They can be used alone or in combination with others. Their simple design allows them to be used in emergency situations with water shutoff, as well as for fire fighting. They are also popular in air conditioning and sewage systems. Many jet-type models are sold with a variety of nozzles.

• reliability;
• no need for constant maintenance;
• simple design;
• wide scope.

Minus - low efficiency (no more than 30%).

Centrifugal pumps

In this type of device, the main working element is disk on which the blades are fixed. They have an inclination in the direction opposite to the direction of movement. The blade is mounted on a shaft, which is driven by an electric motor. The design can be used one or two wheels. In the second case, the blades connect them together.

The principle of operation of a centrifugal pump is based on the fact that water enters the working chamber through the inlet pipe. The medium captured by the rotating blades begins to move along with them. Centrifugal force moves water from the center of the wheel to the walls of the chamber, where increased pressure is created. Due to it, water is ejected through the outlet. Due to the fact that the water is constantly moving, pumps of this type do not create pulsations in the water supply.

Usage centrifugal pumps for domestic purposes allows you to perform various tasks. Often they are used to extract water from a well or well. The water pumped out in this way can be used to equip the water supply of the house, and also used for irrigation of the site. With the help of centrifugal models, it is possible to provide circulation warm water in the heating system: due to the fact that the transfer centrifugal pump does not give pulsation, air will not appear in the system. Various subspecies of such pumps can be used to pump water from basements or pools, to remove fecal matter, and also as drainage machines.

It is worth noting that simple pumps with a centrifugal system are designed for clean water without solid elements. Various subspecies allow you to work with a polluted environment.

Axial models

In devices of this type, no centrifugal force, and the whole process occurs by transferring kinetic energy. In the working chamber, which has a bend, the blades are on the axis. It is located in the direction of the flow. Water moves through the chamber, the axis increases its speed and pressure. Due to this design, the requirements for their production are quite serious. Most often, such pumps are used as a ballast and control system in ships, floating docks and similar equipment.

The main task of such pumps is pumping fresh and salt water. They are used for drainage, supply and purification of water. Axial pumps can have very compact dimensions and be installed inside the water supply.

vortex pumps

Vortex pumps have a similar structure to centrifugal pumps, only in them water is supplied in such a way that when water enters the chamber, it moves tangentially relative to the periphery and shifts to the center of the wheel, from where, under pressure and due to the movement of the blades, it again goes to the periphery, and from there ejected through the outlet pipe. The main difference is that with one revolution of the wheel with blades (impellers) the cycle of suction and expulsion of water occurs many times.

This design allows you to increase the pressure by 7 times even with a small amount of water - this is the fundamental difference between vortex pumps and centrifugal pumps. Just like centrifugal pumps, these models do not tolerate the presence of solid inclusions in the water, and also cannot work with viscous liquids. However, they can be used to pump gasoline, various liquids containing gas or air, and aggressive substances. Minus - low efficiency.

Such pumps are used for various purposes and areas, but their installation is advisable if the amount of substance to be worked with is small, but high pressure is needed at the outlet. Compared to centrifugal models, these devices are quieter, smaller and cheaper.

Classification by type of food

All water pumps have a certain way of being powered - from electricity or from liquid fuel. In the latter case, they must be equipped internal combustion engine. The liquid fuel is a mixture of gasoline and oil or diesel fuel.

Gasoline models are cheaper and quieter. Diesel devices are refueled with diesel fuel. They are more expensive, but fuel is cheaper. Also, they are noisier.

Liquid fuel pumps are also called motor pumps. Their main advantage is ease of use and mobility, that is, they can be used anywhere if there is no electricity.

Electrical Models use for work alternating current. The owner of such a pump does not need to worry about the availability of fuel, but care should be taken to ensure the constant availability of electricity, which is not always convenient.

Liquid quality classification

Different types of pumps impose certain requirements on the purity of the water. All devices can be divided into three types.

1. For pure water. The content of solid particles in it should not exceed 150 grams per cubic meter. These models include surface pumps, as well as well and downhole pumps.
2. For moderately polluted water. Insoluble inclusions from 150 to 200 grams per cubic meter. Drainage, circulation and self-priming types. Also some fountain models.
3. For dirty water. Solids from 200 grams per cubic meter. Drainage and surface sewer models.

Location classification

All pumps are also divided into submersible and external (the more common name is surface). The first type is located directly in the water or partially in it. Models that do not fully submerge are referred to as semi-submersible.

It is worth noting that there are several types of submersible pumps.

1. Vibrating– here the work is based on the electromagnetic field and vibration special mechanism, these types of pumps require certain installation rules. In particular, there are strictly specified distances to the bottom.
2. centrifugal apparatus which have been discussed above.

All submersible pumps can have a motor that is already built into the housing, i.e. it is under water. For some models, it is located on the surface.

Located directly next to the reservoir. In this case, the suction mechanism performs its work through a special hose. The farther the pump is located from the water, the more powerful it must be.

Most often, surface pumps are used in summer cottages and suburban areas. They are highly economical and small in size, which makes them popular for household use. Can be equipped with automation which makes them completely autonomous.

Advice! When using a remote ejector, you can extract water from an impressive depth.

Submersible pumps

Submersible pumps, among other things, are divided by purpose:

• downhole;
• wells;
• drainage;
• fecal.

Downhole have an elongated shape and are used to extract water from wells. Compact dimensions allow lowering into wells of small diameter, however, production can be carried out from a very large depth. Differ in high power of work. They are used only for water with low pollution or completely clean.

Well used for pumping water from mines and wells. The main difference from downhole ones is a larger size and a smaller immersion depth. They are powerful enough to work with water that contains silt, sand or clay. Pretty quiet and don't vibrate.

Main task drains is the pumping of polluted water from basements, trenches, pits and other places. There are varieties with knives for grinding, as well as for working with lightly polluted media.

It has no significant differences from drainage, except that they are designed for heavily polluted water with solids big size(about 35 mm in diameter). They also have knives for shredding garbage. Such pumps can be both submersible and external.

Surface pumps

The main difference between surface pumps is their location near the water. They can be divided into several types:

• self-priming;
• automatic;
• pumping stations.

Self-priming pumps There are non-ejector and ejector. In the first case, water is drawn in by the structure itself, in the second case, by creating a vacuum in the chamber. Used for irrigation, delivery drinking water or for domestic needs, as well as for the intake of water from reservoirs on the surface (rivers, ponds). Water should be clean or slightly contaminated.

Automatic pumps provided with automation, which simplifies the process of use. The pump does not need to be monitored. Automatic pumps are powered by electricity. The machine itself can be installed directly in the model or as a separate system. The main task is to optimize the use, as well as the protective function. For example, the device will stop working if the reservoir becomes shallow, the temperature of the pumped substance rises, or if there are voltage drops in the network.

Consists of the pump itself, check valve, control system and battery. Such a device has a rubber pear mounted inside a metal case. Water is pumped into the pear, and air around it. A special sensor reacts to changes in ambient pressure that occur as the pear is filled with water. When the pressure reaches its maximum, the sensor stops the water supply.

The ease of use of such units is in simplicity and functionality, the ability to use during power outages. They can also provide water to several points at once.

Section one. PUMPS

CHAPTER 1

PURPOSE, PRINCIPLE OF ACTION

AND APPLICATIONS OF PUMPS OF DIFFERENT TYPES § 1. BASIC PARAMETERS AND CLASSIFICATION OF PUMPS

Pumps are hydraulic machines designed to pump liquids. By converting the mechanical energy of the drive motor into the mechanical energy of a moving fluid, the pumps raise the fluid to a certain height, move it to the required distance in the horizontal plane, or force it to circulate in a closed system.

Performing one or more of the above functions, the pumps are in any case included in the equipment of the pumping station, the schematic diagram of which, as applied to the conditions of water supply and sewerage, is shown in fig. 1. 1. In this scheme, to drive the pump, use

Rice. 1.1. circuit diagram pumping station

1 - water intake;2 - pump;3 - drive motor;4- power step-down transformer; 5- power line;6 -valor pipeline;7 -eodovyuk

zuyutsya electric motor connected to the electrical network. Water for another. The working fluid is sucked by the pump from the lower pool and pumped through the pressure pipeline to the upper pool due to the conversion of engine energy into fluid energy. The energy ¦" of the liquid after the pump is always greater than the energy before the pump.

The main parameters of the pumps, which determine the range of changes in the operating modes of the pumping station, the composition of its equipment and design features, are pressure, flow, power and efficiency.

The head is the difference between the specific energies of the liquid & cross sections after and before the pump, expressed in meters. The pressure created by the pump determines the maximum lifting height or pumping range, liquid (respectively, I and L; see fig. 1.1).

Feed, i.e. the volume of liquid supplied by the pump to the pressure pipeline per unit time, is usually measured in l / s or m 3 / h.

The power expended by the pump is necessary to create the desired hood and overcome all types of losses that are inevitable when converting the mechanical energy supplied to the pump into the energy of fluid movement through the suction and pressure pipelines. The pump power measured in kW determines the power of the drive motor and the total (installed) power of the pumping station.

The efficiency factor takes into account all types of losses associated with the conversion of the mechanical energy of the engine into the energy of a moving fluid. Efficiency determines the economic feasibility of operating the pump when changing its other operating parameters (pressure, flow, power).

The history of the emergence and development of pumps shows that they were originally intended exclusively for lifting water. However, at present, the scope of their application is so wide and diverse that the definition of a pump as a machine for pumping water would be one-sided. In addition to the water supply and sewerage of cities, industrial enterprises and power plants, pumps are used for irrigation and drainage of lands, energy storage, "transportation of materials. There are feed pumps for boiler plants of thermal power plants, ship pumps, special pumps for oil, chemical, paper, food and other industries pumps are used in the production of construction works (alluvium of earthworks, dewatering, "pumping out" water from pits, supplying concrete and mortar to structures, etc.), in the development of deposits and the transportation of minerals in a hydraulic way, during hydraulic removal " waste manufacturing enterprises. As auxiliary devices, pumps serve to provide lubrication and cooling of machines.

Thus, pumps are one of the most common types of machines, and their design diversity is extremely large. Therefore, the classification of pumps according to their purpose is very difficult. A classification based on differences in the principle of action seems to be more logical. From this point of view, all currently existing pumps can be divided into the following main groups: vane pumps, positive displacement pumps and jet pumps. A special group is made up of water lifts of some special types.

Vane pumps convert energy due to the dynamic interaction of the flow of the pumped liquid and the blades of the rotating wheel, which is the main working body of the pump.

Displacement pumps operate on the principle of displacement, which is to create a hydraulic system with a variable volume. If this volume is filled with the pumped liquid, and then it is reduced, then the liquid will be displaced into the pressure pipeline.

Jet pumps work on the principle of mixing the flow of a pumped liquid with a jet of liquid, steam or gas, which has a “large supply of kinetic energy.

It should be noted that, despite the large differences in the principle of operation, the designs of pumps of all types, including pumps used in water supply and sewerage systems, must meet the requirements, which primarily include:

reliability and durability of work;

economy and ease of use;

change in operating parameters over a wide range while maintaining high efficiency;

minimum dimensions and weight;

the simplicity of the device, which consists in the minimum number of parts and their complete interchangeability;

ease of installation and dismantling.

The choice of the type of pump in each specific case is made taking into account its operational and design qualities that most fully satisfy the technological purpose of the pumping station in question.

§ 2. DEVICE DIAGRAM AND OPERATING PRINCIPLE OF VANE PUMPS

Vane pumps, mass-produced by the domestic industry and most widely used in the construction of modern water supply and sewerage systems, include centrifugal, axial and vortex pumps. As noted earlier, the operation of these pumps is based on general principle- the force interaction of the impeller blades with the "pumped liquid" flow around them. However, the mechanism of this interaction is different for the pump types listed, which naturally leads to significant differences in their designs and performance.

Centrifugal pumps. The main working body of a centrifugal pump, one of the possible design options for which is schematically shown in Fig. 1.2, is a wheel freely rotating inside the housing, mounted on a shaft. The impeller consists of two discs (front and rear) spaced at some distance from each other. Between the disks, connecting them into a single structure, there are blades smoothly curved in the direction opposite to the direction of rotation of the wheel. The inner surfaces of the disks and the side surfaces of the blades form the so-called inter-blade channels of the impeller, which must be filled with the pumped liquid for normal operation.

When the wheel rotates, for each volume of liquid mass t, located in the interblade canal at a distance G from the axis of the shaft, the centrifugal force will act, determined by the expression

Рц = /ЛСй a Г, (1.1)

where w is the angular speed of rotation of the shaft.

Under the action of this force, the liquid is ejected from the impeller, as a result of which a vacuum is created in the center of the impeller, and increased pressure is created in its peripheral part. To ensure a continuous flow of liquid through the pump, it is necessary to ensure the supply of the pumped liquid to the impeller and its removal from it.

Fluid is supplied through an opening in the front disk of the impeller by means of a suction pipe and a suction pipe. The movement of liquid through the suction pipeline occurs due to the pressure difference above the free surface of the liquid in the receiving basin (atmospheric) and in the central region of the impeller (depression) ..

To drain the liquid, the pump housing has an expanding spiral channel (in the form of a snail), into which the liquid ejected from the impeller enters. The spiral channel (outlet) passes into a short diffuser, forming a pressure pipe, usually connected to a pressure pipeline.

An analysis of equation (1.1) shows that the centrifugal force, and hence the pressure developed by the pump, is the greater, the greater the speed and the diameter of the impeller. Any high-speed motor can be used as a centrifugal pump drive. Most often, electric motors are used for this purpose.

Depending on the required parameters, purpose and operating conditions, a large number of various designs of centrifugal pumps have now been developed, which can be classified according to several criteria.

By the number of impellers distinguish between single-stage (see Fig. 1.2) and multi-stage pumps.

In multistage pumps, the pumped liquid passes sequentially through a series of impellers mounted on a common shaft. The pressure created by such a pump is equal to the sum of the pressures developed

Rice. 1.2. Centrifugal pump

/ - wheel;2 - blades;3 - shaft;4 - grayling;5 - suction pipe;6 - suction pipeline; 7 - pressure pipe;8 - pressure pipeline

every wheel. In "depending on the number of wheels (stages), pumps can be two-stage, three-stage, etc.

By the magnitude of the generated pressure centrifugal pumps are divided into low-pressure (head up to 20 m), medium-pressure (20-60 m) and high-pressure (over 60 m). -

According to the method of supplying "liquid to the impeller, a distinction is made between pumps with a one-sided inlet (see Fig. 1.2) and pumps with a double-sided inlet, or the so-called double-inlet centrifugal pumps (Fig. 1.3).

According to the method of liquid removal From the impeller pumps are divided into scroll and turbine.

In scroll pumps, the pumped liquid "from the impeller enters directly into the spiral channel of the casing and then either discharges into the pressure pipeline or flows through the overflow channels to the next wheels.

In turbine pumps, the liquid, before entering the spiral outlet, passes through a system of fixed blades that form a special device called a guide vane.

According to the layout of the pumping unit (shaft position) a distinction is made between horizontal and vertical pumps.

By way of connection with the engine centrifugal pumps are divided into drive pumps (with a pulley or gearbox), connected directly "to the motors with the help of a coupling, and monoblock, working wheel CO" of which is installed on the elongated end of the motor shaft.

By type of pumped liquid pumps are water, sewer, heating (for hot water), acid, ground, etc.

The pressure of single-stage centrifugal pumps, mass-produced by the industry, reaches 120 m, the flow is 15 m 3 / s. Serial multistage pumps develop head up to 2000 m at 80-

100 l/s. As for the efficiency, depending on the design, it varies over a wide range - from 0.85 to 0.9 for large single-stage pumps to 0.4-0.45 for high-pressure multistage pumps. and multi-stage, can be much higher.

Axial pumps. The impeller of the axial pump (Fig. 1.4, a) consists of a sleeve on which several blades are fixed, which are a streamlined curved wing with a twisted front edge running on the flow.

If we consider an ideal fluid moving without loss, and assume that the pressure at an infinite distance is constant, then with the movement of the blade profile caused by the rotation of the impeller b According to the Bernoulli equation, due to the change in the flow velocity, the pressure above the profile should increase, and under the profile, it should decrease. This creates a force effect of the blade on the flow, the result of which R(Fig. 1. 4, b) can be decomposed into two components: force Y, normal to the direction of the oncoming flow, which is called the lifting force, and the force x, directed along the flow and is called drag.

The lifting force, referred to the unit length of the blade, is determined by the formula, which is a special case of the general theorem

Rice. 1.4. Axial pump

a - circuit diagram of the device:1 -

wheel; 2 - camera;3 - straightening apparatus;4 - withdrawal; b-forces, "acting wa

blade profile

SJ R

Rice. 1.3. The flow part of a double-sided centrifugal pump

I - suction nozzle; 2 - Working wheel; 3 - passing >shaft; 4 - ggodshiggaiien; 5 - spiral olvod; 6 - pressure paggrubak

1 - wheel;2 - frame;3 - cavity;4, b - "a / pair" suction nozzles;6 - sealing aysgup

N. E. Zhukovsky about the lifting force acting on a body of arbitrary shape:

Y= C y r I

Where C y is a coefficient depending on the shape of the profile and the angle of attack; p is the density of the medium;

I- blade profile chord length;

raVoo is the relative velocity of the unperturbed flow.

The impeller of the pump rotates in a tubular chamber, due to which the bulk of the flow within the impeller moves in the axial direction, which, by the way, determined the name of the pump.

Moving progressively, the pumped liquid is simultaneously somewhat twisted by the impeller. To eliminate the rotational movement of the liquid, a straightening apparatus is used, through which it passes before exiting into the elbow, which is connected to the pressure pipeline. The liquid is supplied to the impellers of small axial pumps using conical nozzles. In large pumps, chambers and curved suction pipes serve this purpose. relatively complex shape.

Axial pumps are produced in two modifications: with impeller blades rigidly fixed on the bushing and with rotary blades.

Changing within certain limits the angle of installation of the impeller blades allows you to maintain a high value of the pump efficiency in a wide range of changes in its operating parameters.

As a drive for axial pumps, as a rule, electric motors of a synchronous and asynchronous type are used, which are directly connected to the pump using a coupling. Pump units are manufactured with a vertical, horizontal or inclined shaft.

The delivery of mass-produced axial pumps by the domestic industry ranges from 0.6 to 45 m 3 / s at heads from 2.5 to 27 m. Thus, compared to centrifugal pumps, axial pumps have a significantly higher flow, but less pressure. The efficiency of high-performance axial pumps reaches 0.9 and higher.

vortex pumps. The impeller of a vortex pump (Fig. 1.5). It is a flat disk with short radial straight blades located on the impeller shaft. In the body there is an annular cavity, into which the wheel blades enter. The inner sealing protrusion, tightly adjacent to the outer ends and side surfaces of the blades, separates the suction and discharge pipes connected to the annular cavity.

When the wheel rotates, the liquid is carried away by the blades and at the same time twists under the influence of centrifugal force. Thus, in the annular cavity of the operating pump, a kind of paired annular vortex motion is formed, which is why the pump is called vortex. A distinctive feature of a vortex pump is that the same fluid particle, moving along a helical trajectory, takes part in

Rice. 1.6. Diagonal pump (¦production of the GDR)

1 -.suction pipe;2 - Working wheel;3 - pump housing;4 - straightening apparatus;5 - radial bearing;6 - withdrawal

The line from the entrance to the annular cavity to the exit from it repeatedly enters the interblade space of the impeller, where each time it receives an additional increment of energy, and, consequently, pressure. Due to this, the vortex pump is able to develop a head that is 2-4 times greater than a centrifugal pump, with the same wheel diameter, i.e., at the same circumferential speed. This, in turn, leads to significantly smaller overall dimensions and weight of vortex pumps compared to centrifugal ones.

The advantage of vortex pumps is also the fact that they have a self-priming capacity, which eliminates the need to fill the casing and the suction line of the pump with the pumped liquid before each start-up.

The disadvantage of vortex pumps is the relatively low efficiency (0.25-0.5) and the rapid wear of their parts when operating on liquids containing suspended solids. Serially produced vortex pumps have a flow from 1 to 40 m 3 /h and a head from 15 to 90 m.

Domestic industry also produces combined centrifugal-vortex pumps, in which a centrifugal-type impeller and a vortex impeller are placed in one housing on one shaft. In this case, the centrifugal stage creates the necessary boost "of the vortex stage and increases the overall efficiency of the pump. At the same feed rates, the head of centrifugal vortex pumps reaches 300 m.

Among the pumps that have not yet been sufficiently mastered by the domestic industry, but have found wide distribution in water supply and sewerage systems abroad, are the so-called diagonal pumps (Fig. 1.6), in which the fluid flow passing through the impeller is not directed radially , as in centrifugal pumps, and not parallel to the axis, as in axial pumps, but obliquely, as if along the diagonal of a rectangle made up of radial and axial directions.

The inclined flow direction creates the main design feature of diagonal pumps - the location of the impeller blades perpendicular to the meridional flow and inclined to the pump axis. This circumstance makes it possible to use the joint action of lifting and centrifugal forces to create pressure.

The impellers of diagonal pumps can be closed (see Fig. 1.6, a) or open (see Fig. 1.6, b) type. In the first case, the general design of the wheel approaches the centrifugal, and in the second - to the axial wheel. The blades of open-type impellers for a number of pumps are swivel, which is their undoubted advantage.

The liquid is discharged from the impeller of a diagonal pump using a spiral channel, as in centrifugal pumps, or using a tubular elbow, as in axial pumps.

In terms of their operating parameters (flow, head), diagonal pumps also occupy an intermediate position between centrifugal and axial pumps.

§ 3. SCHEMES OF THE DEVICE AND PRINCIPLE OF OPERATION OF VOLUMETRIC PUMPS

Depending on the design, purpose and operating conditions, positive displacement pumps can be classified as follows:

with reciprocating motion of the working body;

with rotational movement of the working body.

The first group includes piston, plunger and diaphragm pumps. The second group includes gear and screw pumps.

A single-acting piston pump (Fig. 1.7) consists of a housing, inside of which there is a working chamber with a suction l pressure valves and a cylinder with a reciprocating piston. Suction and pressure pipelines are connected to the body. The rotational movement of the drive motor shaft

The body is converted into a reciprocating piston movement using a classic crank mechanism.

When the piston moves to the right, a volume of liquid is sucked into the cylinder,

V - F S,

where F- piston area;

5 - piston stroke.

With the piston stroke to the left, the same volume is pushed into the pressure pipe. Thus, a single-acting pump performs one suction cycle and one discharge cycle (working) per revolution of the crank.

The ideal pump flow in this case is

Qct = F S p, (1.3)

where P.- crank speed, min - ’.

The actual supply Q is less than ideal due to delayed closing of the pressure and suction valves, leakage through valves, stuffing box and piston seals, as well as due to the release of air or gases from the pumped liquid. Therefore, the actual supply

Q \u003d 1 lo6 ^ Srt, O- 4)

where m | about - the volumetric efficiency of the pump or the filling factor.

The value of the filling factor t] 0 b depends on the size of the pump and varies within 0.9-0.99. *

Theoretically, a piston pump can develop any pressure. However, in practice, the pressure is limited by the strength of individual parts, as well as the power of the engine that drives the pump.

The flow of a single-acting piston pump, calculated by formula (1.3), is a time-averaged value. The instantaneous volume of liquid supplied by the pump is equal to the area of ​​the piston F, multiplied by its speed v. Since the reciprocating movement of the piston is carried out using a crank mechanism, the piston speed changes from zero in the dead positions of the crank to a maximum in the middle position. Similarly, the pump flow changes during the stroke of the piston. Combined with the complete lack of flow during the suction cycle, this circumstance determines the main disadvantage of single-acting piston pumps - intermittent and uneven flow.

The change in displacement of a piston pump per revolution of the crank can be represented graphically. Such graphs make it possible to visualize the sequence of injection and suction processes, as well as to assess the degree of uneven supply, i.e. determine how many times "the maximum feed exceeds the average.

According to the theory of crank mechanisms, we can assume that the change in the instantaneous speed of the piston in time with a sufficient degree of approximation follows the sinusoidal law

u = r co sin a, (1.5)

where r=S/2 - crank radius;

oz \u003d 2ll / 60 - angular velocity;

a =f(t)- crank angle, which is a function of time t.

Accordingly, the instantaneous delivery of the pump

Q= F v = F g co sin a. (1.6)

The change in function (1.6) during one revolution of the crank is shown in fig. 1.8, a.

a)

Rice. >1.8. Displacement curves for piston pumps

a - single action;b - two-star action; ¦ pre-piston pump

Ryas. "1.9. Double-acting piston pump

Let us replace the area bounded by the sinusoid and the x-axis of the graph by the area of ​​an equal-sized rectangle built on a straight line segment of length 2n G. Both of these areas graphically express the volume of liquid supplied by the pump to the pressure pipe during one revolution of the crank. Height h The rectangle will thus represent, on the accepted scale, the value of the average feed, and the largest height of the sinusoid will represent the value of the maximum feed. The ratio of the maximum feed to the average (the degree of uneven feed) will be:

QMaKc _ F

The area of ​​the rectangle, according to the construction,

2itrh = FS - F -2 G,

h =- I

Omya KG F

QcpFin

i.e., for a single-acting piston pump, the maximum flow exceeds the average by 3.14 times.

There are several ways to reduce the uneven movement of fluid in a system connected to a piston pump. One of them is the use of double-acting piston pumps (Fig. 1.9), in which chambers with valves are located on both sides of the cylinder and therefore the movement of the piston in any direction is working: the suction cycle in the left chamber corresponds to the injection cycle in the right, and vice versa.

The flow of a double-acting piston pump is almost twice that of a single-acting pump of the same geometric dimensions and can be calculated by the formula

Q = 1 lo6 (2F - f) Sn, (1.8)

where f- sectional area of ​​the rod.

When constructing a graph for changing the supply of a double-acting piston pump, using the same methods, we obtain two sinusoids (Fig. 1.8.6).

In this case

2nrh = 2F S = 2 F-2r, I

Hence,

1.57, ¦ (1.9)

Q cp 2 FF i 2

i.e., the maximum feed exceeds the average by 1.57 times.

Another very effective way is to use multi-piston pumps with cylinders connected in parallel, the pistons of which are driven by a common crankshaft. Consider, for example, the flow diagram of a three-piston pump, consisting of three single-acting pumps, the cranks of which are located relative to each other at an angle of 120°.

To obtain the total feed curve, it is necessary to build three sinusoids shifted by 120 ° one with respect to the other, and then sum their ordinates (Fig. 1.8, in). The area of ​​the diagram, bounded at the top of the total curve, depicts the flow of all three cylinders. The largest ordinate of the graph is F, since it is obtained by adding two segments ab and bc, each of which is

F sin 30° = 0.5 F.

In this case we have:

Degree of uneven feed

\u003d -? - \u003d - \u003d 1.047. (MO)

Qcp 3F (ts 3

In order to ensure the most uniform supply of piston pumps and prevent inertial actions of the masses of the liquid filling the system, the device of air caps is also practiced. supply. ,During the suction cycle, the air expands and the process of expelling liquid into the discharge pipe continues.

Plunger pumps differ from piston pumps in the design of the displacing body. Instead of a piston, the owl has a plunger, which is a hollow cylinder moving in a sealing gland without touching the inner walls of the working chamber. In terms of hydraulic parameters, piston and plunger pumps are the same. In operation, plunger pumps are somewhat simpler, since they have fewer wear parts (there are no piston rings, cuffs, etc.).

Instead of a piston, diaphragm pumps have a flexible diaphragm (membrane) made of leather, rubberized fabric or synthetic material.

The delivery of commercially available piston pumps varies from 1 to 150 m3/h at heads up to 2000 m.

The gear pump is shown schematically in fig. 1.10. The working body of the pump is two gears: driving and driven, placed in a housing with small radial and end clearances. When the wheels rotate in the direction indicated by the arrows, the liquid flows from the suction cavity into the cavities between the teeth and moves to the pressure cavity.

The delivery of a gear pump, consisting of two wheels of the same size, "is determined by the expression

Q = 2 f I z p m]rev, (1.11),

where f- cross-sectional area of ​​the cavity between the teeth;

1 - gear tooth length;

2- number of teeth.

The volumetric efficiency of a gear pump takes into account the partial transfer of liquid back to the suction cavity, as well as the flow of liquid through the gaps. On average, it is 0.7-0.9.

Gear pumps are reversible, i.e. when the direction of rotation of the gears changes, they change the direction of flow in the pipelines connected to the pump.

Screw pumps (Fig. 1.11) have screws of a special profile, the engagement line between which ensures complete sealing of the discharge area from the suction area. When rotating the screws, this line moves along the axis. The length of the screws to ensure tightness in all their positions should be slightly larger than the pitch of the screws. The liquid located in the cavities of the screws and limited by the body and the pinching line of the screws, is displaced into the injection area during their rotation. In most cases, screw pumps are made with three screws: the middle one is the leading one and two lateral ones are the driven ones. The supply of a screw pump with cycloid gearing is determined by the expression

Q \u003d 0.0691 d 4, (1.12) -

whered B - diameter of the pitch circle of the screws.

Screw pumps provide a uniform schedule of fluid supply over time.

Theoretically, the flow of rotary pumps, like all positive displacement pumps, does not depend on the pressure they create. In fact, there is a slight decrease in flow with increasing pressure, determined by an increase in the flow of fluid through the gaps inside the pump. The displacement of fluid from the pump into the pressure pipe is fundamentally independent of the resistance encountered. Therefore, the pressure of volumetric pumps is determined by the resistance of the external network.

§ 4. SCHEMES OF THE DEVICE AND PRINCIPLE OF OPERATION OF JET PUMPS AND WATER LIFTS

The action of jet pumps is based on the principle of transferring kinetic energy from one stream to another, which has less kinetic energy. The creation of pressure in pumps of this type occurs by direct mixing of both flows, without any intermediate mechanisms. Depending on the purpose of the pump, the working and pumped media (liquid, steam, gas) may be the same or different.

Consider the working process of a jet pump and find the relationships that determine its main parameters, using the example of a water jet pump (hydroelevator), in which the working and pumped medium is water.

Water jet pump. In a water jet pump .. (Fig. 1.12, a) water under high pressure through a pipe ending in a nozzle is fed into the inlet chamber. Flowing out of the nozzle at high speed in the form of a jet, it carries along the water that fills the mixing chamber*. atmospheric pressure. From the mixing chamber

Rice. 1.12. water jet pump

1 - suction pipeline;2 - pipe;3 - nozzle;4 - inlet chamber; 5 - camerafunnynia;6 - diffuser; 7 - pressure pipeline

cue, the total flow is directed to the diffuser, where, by reducing the flow velocity, the pressure necessary for the movement of the liquid through the pressure pipeline is created. The constant filling of the inlet chamber with pumped water occurs from the receiving tank through the suction pipeline.

The pressure developed by a water jet pump, according to the definition given in § 1, is the difference in specific energies in the outlet section III-III and in the input /- I. Without taking into account losses, it can be equated to the energy increment in the section between the sections II-// and I-I mixing chambers.

Using the Bernoulli equation for these two sections and introducing dimensionless parameters s = F K .Jf c and q - Q/Qc, where F K . C and f c respectively the cross-sectional area of ​​the mixing chamber and the jet; Q c - nozzle (jet) flow rate, after a series of transformations, the following expression can be obtained:

i= - 2 g

The actual pressure of the water jet pump will, of course, be less than that calculated by equation (1.13), since losses in the receiving chamber, mixing chamber and diffuser must be subtracted from it. Nevertheless, expression (1.13) makes it possible to analyze the change in the main parameters of water jet pumps. First of all, it clearly shows that

the pressure developed by the pump is proportional to -, i.e. pressure N s, with

which water is supplied to the nozzle. In addition, the pressure is determined by the relative flow q and geometric parameter s.

On fig. 1.12 b these relations are constructed for s== 1.5; 2.5 and 4. The graph shows that with an increase in flow, the pressure developed by the water jet pump decreases; an increase in the parameter s also causes a decrease in the head.

The efficiency of a water jet pump is determined by the ratio of the useful energy of the liquid to the summed up. The supplied energy can be expressed as follows:

^SUB ~ Qc P Hz" (1*14)

Useful energy is determined by pressure and useful supply. The latter can be defined in different ways. If a water jet pump is used to pump water, only the flow rate is useful. Q, entering the inlet chamber. In this case

9n = Q?gH, and J) The PD of the water jet pump will be:

The actual values ​​\u200b\u200bof K "PD, achieved in practice under such conditions, do not exceed 0.25-0.3.

If the water jet pump is used for water supply or for cooling, then the total supply Q + Qc is useful, and then

3n = (Q + Qc)pgtf. and the expression for efficiency will look like:

, (Q + Qc)# n 1P

¦ 11" Q"H" ¦(1L6)

In this case, of course, the efficiency is higher and can reach 0.6-0.7.

The water-jet pump (hydroelevator) is very simple in design and is available for local production. However, it should be borne in mind that correct sizing and careful manufacture are required to ensure its good performance. Of essential importance is the shape of the nozzle, the distance from the nozzle to the mixing chamber, the shape of the mixing chamber and diffuser.

A number of devices are also used to transport and lift liquids, which cannot be called pumps in the strict sense.

this word. Some of them are used in the construction of water systems.

supply and sewerage. These primarily include air water lifts, hydraulic rams and screw pumps.

The air lift (airlift) consists of a vertical pipe, the lower end of which is immersed under the level of iodine in the receiving tank (Fig. 1.13). An air duct passes inside the pipe, through which compressed air is supplied by a compressor and sprayed using a nozzle located at a depth N p. The density of the resulting air-water mixture p cm is much less water density, p, as a result of which the mixture rises through the pipe above the water level in the tank to a height. N.

According to the principle of communicating "vessels in equilibrium

N p p =[N a N ) Pcjj.

From here we find the height H(pressure) airlift:

I \u003d n a R ~- Rs - . (1.17)

The relationship between feed and other operating parameters of the air lift can be found based on the following reasoning.

The energy transmitted by the compressor in 1 s of the volume Q B .arM, m 3, of air, referred to atmospheric pressure, when it is compressed from atmospheric pressure r and tm to pressure R, under which it is supplied to the nozzle, in an isothermal process it will be:

, N == RatmFv.atm ^ _

R atm

The useful work produced by compressed air consists in lifting Q, m 3, water-in 1 s, to a height R:

Nn = Pg O. N¦

Considering the inevitable losses by introducing the airlift efficiency rj, one can write:

N n ~ N t)

?gQH = T\p arM Q B aTM In -- . (1.18)

P atm

Expressing pressure p in Pa at p in \u003d YuOO kg / m 3 and Ratm=OD MPa, from equation (1.18), after a series of transformations, we obtain the desired dependence:

Q \u003d\u003d T] 1p (0.1Rn + 1). (1.19)

From the formula (=1.19) it follows that the airlift feed decreases with increasing lift height N. At constant pressure and depth of the airlift, it increases with increasing Q B .aTM- It would seem that there are unlimited possibilities for increasing Q. However, it turns out that with too much air flow, the medium in the water pipe ceases to be homogeneous, which sharply reduces the efficiency of the airlift and leads to a decrease Q and I.

In table. 1.1 shows the approximate values ​​of the necessary immersion of the nozzle and the volume of supplied air, which ensure the optimal operation of the airlift.

TABLE.1.1

	ValuesH, m
Options
HJH					0,65-0,75
I - Qa.aTM^

As for the efficiency of the air lift, even under favorable conditions it does not exceed 0.3-0.4, and taking into account losses in the compressor, the overall efficiency of the installation is usually 0.1-0.2. Thus, according to q energy indicator

lam it's not very good effective method lifting water.

N p p

Rice. 1.13. lift

1 - receiving tank;2 - air tube from tsom-ggressor;3 - water-lifting "pruba";4 - well casing pipe;5 - nozzle

At the same time, the airlift device is extremely simple, it has no moving parts and therefore is not afraid of the ingress of suspended particles. It is convenient enough for lifting water from wells, especially small diameter ones that do not include any pump. The air lift is easy to assemble at any site using a mobile compressor to supply air. The diameter of the riser pipe can be determined by the speed of the mixture directly above the nozzle from 2.5 to 3 m/s I

Air

I - auger; 2 - tray;3 -broadcast; - 2

4 - electric motor

by spout speed from b to 8 m/s; the diameter of the air pipe is taken according to the air speed of 5-10 m / s.

Hydraulic ram. In a hydraulic ram, the rise of water is carried out by the energy of a hydraulic shock, which is periodically repeated due to the abrupt closing of the valve under the action of a natural flow. An indispensable condition for the operation of the ram is its location below the water level in the source.

The ram installation (Fig. 1.14) consists of a feed pipe, shock and discharge valves, an air cap, a pressure pipe and a pressure tank.

When the ram is put into operation, the water from the source enters through the supply pipe to the shock valve and, under pressure R, flows out of it at an increasing speed. When the speed increases to a certain limit, the pressure in the gaps above the valve decreases, and the pressure on the valve from below increases so much that the total pressure force overcomes the weight of the valve and closes it abruptly, blocking the way for water to escape. In this case, a water hammer occurs, as a result of which the pressure in the supply pipe rises above the pressure in the air cap for a certain short period of time, the discharge valve opens and water flows through it into the air cap, and then through the pressure pipeline into the upper tank, rising to a height of R 2 . During the subsequent water hammer phase, a vacuum is created in the feed pipe and the shock valve is reopened by atmospheric pressure and partly by its own weight (or spring). At the same time, under the pressure of water in the air cap, the discharge valve closes and the ram again returns to its original position. The cycle then repeats itself automatically. The number of hydraulic shocks depends on the adjustment of the ram and ranges from 20 to 100 per minute.

pressure N\ choose depending on local topographic conditions - from 1 to 20 m. The length of the feed pipe is taken equal to (5 ...

8) I b The maximum lifting height I 2 reaches 100-120 m.

Screw pump (Fig. 1L5). The main working body of this type of water lifts is the auger, which is a shaft with a spiral wound around it. As a rule, the auger is made with a three-way spiral, which ensures the supply of water and equal strength of the auger at any angle of rotation. The auger, mounted obliquely, rotates in a tray usually made of concrete. Peripheral speed of the auger 2-

5 m/s corresponds to a speed of 20-100 min -1 depending on the screw diameter. To obtain such a speed, the drive motor is connected to the screw shaft through a gearbox or through a V-belt drive.

The angle of inclination of the auger is assumed to be 25-30 °, which, with a typical auger length of 10-15 m, provides a lifting height of 5-8 m. take a longer auger length, thereby increasing the lifting height.

The flow rate of screw pumps commercially produced abroad ranges from 15 to 5000 l / s at a lifting height of 6-7 m. The average efficiency of a screw pump is about 0.7-0.75 and remains almost constant over a wide range of flow changes.

§ 5. ADVANTAGES AND DISADVANTAGES OF PUMPS OF VARIOUS TYPES

If we talk about the possible flow, then as it increases, the pumps are arranged in the following order (Fig. 1L6): positive displacement pumps, centrifugal pumps and axial pumps. If, however, the maximum possible value of the head is considered as the main parameter, then the order will be reversed. As for water lifts of special types, all of them, including jet pumps, in the R-Q field occupy areas adjacent to the coordinate axes and are characterized by low values ​​of either pressure or flow. Thus, almost the entire range of heads from 1-2 to 10,000 m and flows from several liters to 150,000 m 3 per hour is covered by a large number of standard sizes well mastered by the pump industry.

At the same time, when deciding on the use of a pump in a particular technological installation, in addition to its operating parameters, its operational qualities acquire decisive importance, which, in particular, was discussed in § 1.

In this regard, let us analyze the advantages and disadvantages of the pumps we have considered and the areas of their possible application in the structures of water supply and sewerage systems.

^. Vane pumps. Centrifugal and axial flow pumps provide smooth and continuous flow of pumped liquid at high efficiency values. A relatively simple device ensures their high reliability and sufficient durability. The design of the flow path of vane pumps and the absence of friction surfaces allow the possibility of pumping contaminated liquids. Ease of direct connection to high

1 10 100 1000 10000 100000 Orft

Rice. 1L6. Limits for changing the parameters of pumps of various types

co-rotating drive motors contributes to the compactness of the pump unit and increase its efficiency.

All these positive qualities of centrifugal and axial pumps have led to the fact that they are, in fact, the main pumps of all water supply and sewerage facilities. Centrifugal and axial pumps are also widely used in systems for the circulation of liquids, in ship-lifting structures, at irrigation and drainage pumping stations.

The disadvantages of centrifugal pumps include the limited use of them in the area of ​​low flows and high pressures, which is explained by a decrease in efficiency with an increase in the number of stages. Known difficulties in the operation of pumping units with centrifugal pumps also arise due to the need to fill them with the pumped liquid before putting them into operation.

These shortcomings are absent in vortex and centrifugal-vortex pumps. However, due to their low efficiency, they are used only in small autonomous systems water supply and, in addition, are used as auxiliary (see § 44) at large water and sewer pumping stations.

Volumetric pumps. The undoubted advantages of piston and plunger pumps are high efficiency and the ability to supply small volumes of liquid under arbitrarily high pressure. At the same time, the uneven supply, the difficulty of connecting to the drive motor, the presence of easily worn out valves, low-speed, and, consequently, large dimensions and weight exclude the possibility of their use at modern high-performance pumping stations of water supply and sewerage systems. Only extremely rarely are vertical piston pumps still used to lift water from wells of "small diameter (up to 200 mm). Modified piston pumps are designed to supply concrete and mortar during construction work (see § 36).

Volumetric pumps with rotational movement of the working body are structurally simpler and provide a smooth supply of the pumped liquid. However, the very low rates of gear and screw pumps, combined with their ability to pump viscous liquids, determined their application as feed pumps in hydraulic, automation and lubrication systems.

¦Water jet pumps. The advantages of hydraulic elevators are small size, simplicity of design, the ability to pump liquids with a high content of suspended sediments and high reliability. Water jet pumps are widely used in the production of earthworks by hydromechanization. They are also used for pumping water from deep wells, artesian wells, pits, trenches, to lower the level ground water e wellpoint installations. In sewage treatment plants, water-jet pumps are used to lift sludge settled in sand traps and to mix sludge in digesters. In large pumping stations, water jet pumps are used as auxiliary pumps to suck air from the main pumps before they are started and to increase the suction capacity of centrifugal pumps.

The disadvantages of water jet pumps include low efficiency and the need to supply a large volume of working water under pressure. Therefore, the use of a hydraulic elevator in each specific case should be justified by economic calculations.

Air lift. The simplicity of the device, easy maintenance and reliable operation of airlifts allow them, under certain conditions, to successfully compete with centrifugal pumps when lifting water from deep wells, supplying chemicals and sludge to water and sewage treatment plants. However, the need for a "great deepening of the nozzle and the low efficiency of the installation force each time to justify the decision made by a feasibility comparison of options using pumps of various types.

Hydraulic rams, characterized by low flows, are used in small autonomous water supply installations with a seasonal, as a rule, operating mode.

Screw pumps can be very effective when pumping sewage and sludge to a small height (5-8 m).

The pump is a unit designed to move various substances with different volumes different composition and features. The variety of types of pumping equipment requires a clear classification so that consumers can quickly select the right model in accordance with their own needs.

Pumps are classified into types according to the following criteria:

• areas of use;
• operating principle;
• design features;
• destination and installation location.

In this case, a certain model can be characterized for each type of classification.

Scope of use

household- intended for:

• creating pressure in autonomous heating systems of private residential buildings;
• water supply in the absence of centralized sources of supply;
• pumping wastewater in sewerage systems when it is impossible to provide the necessary slopes in pipelines, etc.

The performance of household pumps is much lower compared to industrial ones.

Industrial- are used:

• for the supply of water necessary for the operation of industrial installations;
• in water treatment plants and cooling systems;
• in fuel and lubricant supply systems;
• for washing the nodes of mechanisms and equipment;
• for transportation of oil products;
• in water supply systems of boiler plants;
• in the chemical industry for pumping aggressive liquids, etc.

The power of industrial types is of great importance for ensuring the profitability of enterprises, including those operating in the service sector, therefore, when selecting pumps, they do not save on their performance and cost.

Operating principle

According to this criterion, the equipment can be divided into positive displacement and dynamic pumps.

Principle of operation positive displacement pumps consists in changing the volume of the inner chamber in various ways, which creates pressure that induces the movement of the pumped liquids. Their main feature is the self-suction of new volumes of the pumped substance due to the creation of a vacuum in the chamber after the removal of the previously received substance from it. These include the following types:

Functioning dynamic pumps is carried out due to the forces of movement in the absence of self-priming and is characterized by the balance of work, the uniformity of the supply of the pumped liquid and the exclusion of vibration. These include:

Design features

By design features, pumps can be distinguished with the naked eye, especially in cases where it is not possible to install it in the planned place due to incompatible connections and inappropriate sizes.

In addition, even one type of pump may have differences in the internal structure. For example, all rotary pumps are equipped with rotors, but the working elements are cams, blades, screws, etc. - they may differ.

Another clear difference between different types of pumps in design is horizontal or vertical execution.

Purpose and place of installation

Widely used pumps used to supply water from wells, tanks and wells are divided into surface and submersible.

Surface pumps

Water is supplied by suction through a flexible hose or pipe, which is lowered into the well. They can be equipped with an automation system that ensures the flow of water on the signal of a sensor that is triggered when the taps in the system are turned on. Such a system is called a pumping station.

Submersible pumps

Wells are lowered directly into the water itself. They are equipped with floats that stop the pump in the absence of water.

The purpose of drainage pumps is to pump water from flooded underground rooms, drainage systems, reservoirs, pools, systems autonomous sewerage. The pumped water is most often contaminated, so the design of the equipment is designed for minimal contact with water of rubbing parts.

Circulation pumps are used in autonomous heating systems to create pressure and accelerate the circulation of the coolant. They differ small size, noiseless operation, easy integration directly into the pipelines of the heating system. When choosing them, you should use simple rule: the equipment must pass through itself 3 times the volume of coolant within an hour.

Purpose fecal pumps- pumping of polluted and sewage waters, including domestic sewage containing a large number of large impurities. Such wastewater is removed from the sewerage systems of residential buildings, washing restaurants and cafes, laundries and bathhouses, hotels, etc. Usually, household wastewater contains large particles that can clog the pipes of sewer systems; to prevent this, the design provides for a mechanism that grinds large particles to the desired fraction.

A pump is a type of hydraulic machine that moves fluid by suction and discharge using kinetic or potential energy. The pump is required for use in fire fighting technical means, for the removal of liquids in residential areas, for fuel supply and many other purposes. According to the scope, design, principle of operation, there are different types and types of pumps. When using pumps for various purposes, you need to know what types are and how they differ.

General classification

First of all, pumps are divided by scope into domestic and industrial. Household pumps are used in households, industrial - in enterprises and in special services (fire). A separate classification of pumps according to the type of working chamber involves the division into dynamic and volumetric pumps.

Types of pumps and their classification

The various classifications of pumps are based on an understanding of what types of pumps exist and how they differ. Pumps are divided into several types, which, in turn, are divided into categories.

By technical specifications:

• depending on the volume of liquid moved per unit of time;
• pressure and pressure;

By area of ​​application:

• household;
• industrial.

Division of pumps by application

The scope of pumps is very wide. Today they are used in almost all areas: construction, industry, mining, and the development of fire extinguishing systems. Also used on a small scale Various types pumps, and their application ranges from domestic use for irrigation, to installation in water supply and heat transfer systems. Depending on the scope of application, types and types of pumps are distinguished. Below are descriptions, their characteristics and varieties.

Pump types

For the intended purpose:

• submersible pumps;
• surface pumps.

By way of power supply:

• electric pumps;
• liquid fuel pumps.

Depending on the type of water:

• for clean water;
• for moderately polluted water;
• for highly polluted water.

Types of household pumps and their scope

According to the scope of application, pumps are divided into domestic and industrial. Household pumps are surface and submersible. For domestic use, the first type is more often used. Surface pumps are used for autonomous water supply of private houses, irrigation of the adjacent territory, pumping water from basements and ponds, increasing pressure during autonomous water supply to private house.

There are four types of household pumps:

• garden;
• pumping stations;
• drainage;
• deep.

Description and characteristics of pumps

There are 2 types of pumps: surface and submersible. Surface pumps are installed at ground level, a hose is lowered into a well or pit. If the pump is equipped automatic system on-off when water is supplied, it is called a station. Submersible pumps include: drainage pumps, fecal pumps, circulation pumps, pumps installed in wells and boreholes.

Varieties of pumps by design

By design, all pumps differ from each other. They can be vertical and horizontal. All pumps differ in their assembly, depending on the model, blades, blades, screws can be used in them.

Classification according to the principle of operation - according to the type of working chamber

There are types of pumps according to the principle of operation and design. They are divided into positive displacement and dynamic pumps.

1. Positive displacement pumps are those in which the liquid moves due to a change in the volume of the liquid chamber under the action of potential energy.
2. Dynamic pumps are mechanisms in which the fluid moves with the chamber under the action of kinetic energy.

Dynamic pumps, in turn, are divided into vane and jet.

Separately, types of volumetric pumps are distinguished according to the principle of operation, depending on the design:

1. Rotary pumps are a one-piece housing, with a certain number of blades / blades, set in motion by a rotor.
2. Gear pumps are the simplest type of mechanism, consisting of gears coupled together, set in motion by a forced change in the cavity between the gears.
3. Impeller - blades are enclosed in an eccentric body, squeezing out liquid during rotation.
4. Cam - pumps, in the body of which 2 rotors are enclosed, which, when rotated, pump liquids of varying degrees of viscosity.
5. Peristaltic - the body includes an elastic sleeve in which the liquid is located. When the additional rollers rotate, the liquid moves along the sleeve.
6. Screw - pumps consisting of a rotor and a stator. When the rotor rotates, the liquid begins to move along the axis of the pump.

There is also a division of dynamic pumps according to the principle of operation:

1. Centrifugal - includes an impeller, inside which there is a liquid, when the wheel rotates, the particles acquire kinetic energy, centrifugal force begins to act, under the influence of which the liquid passes into the motor housing.
2. Vortex pumps - according to the principle of operation, they are similar to centrifugal ones, but they are smaller overall and have a lower efficiency.
3. Jet - based on the transition of potential energy into kinetic.

The vortex type pump is the most commonly used due to its ease of installation. In domestic needs, such a unit is installed in country houses to provide water supply. Water circulation is provided by liquid supplied to the blades located in the pump housing. Key elements here is the wheel, to which water is supplied through the inlet. Also, such a pump is used for wells, as they create high pressure. They have the ability to self-priming and can process not only a liquid, but a gas-water mixture.

Centrifugal pumps are often used for domestic and industrial purposes:

• for the organization of water supply systems at industrial enterprises;
• for the organization of water supply systems for residential areas;
• for irrigation systems.

These pumps are easy to operate, as the principle of operation is quite simple. The main load is taken by the wheel with blades, to which the liquid is supplied, however, if there is no liquid inside, the pump will fail. Most of these pumps are surface. This reduces their performance. Centrifugal-type submersible pumps require a high-quality pressure-tight casing.

Classification by purpose

By appointment different kinds pumps are used for industrial purposes (in the food, chemical, paper industries). For domestic purposes, pumps are used in construction, pumping water from wells and wells, for drilling a well, for heat supply. Well drilling requires the use of pumping station or submersible pump. The pump provides water supply from the well under low pressure.

In automobiles and industrial machines, pumps are auxiliary devices.

In the extraction of minerals, various types of pumps are used for drilling a well, arranging the territory adjacent to the well, pumping fluid, and processing liquids. In industry, pumps are installed at enterprises for the hydraulic removal of production waste.

Pumps used in the food industry often have devices for crushing materials (except stone and metals) to prevent clogging of the pipeline.

Separately allocate pumps for fire extinguishing. The design of such pumps provides for the supply of water under high pressure.

Drainage pumps are submersible, they are characterized by the presence of a grinding and filtration system.

Pressurizing pumps are used in systems where an increase in pressure is required during operation (heat supply, water supply).

There are types of water pumps according to their purpose:

1. Water-lifting.
2. Circulating.
3. Drainage.

Depending on the scope of use, there is a classification of water pumps according to the principle of operation.

1. Water lifting pumps are used to extract fluid from wells or wells.
2. Circulation types of pumps are used to move fluid in heating, air conditioning and water supply systems.
3. Drainage pumps are used to pump fluid from basements and sewers.

Classification by type of pumped medium

Depending on what type of liquid will pass through the pump, design and other features will vary.

Pumps are used for pumping:

• clean liquid and liquid of low contamination;
• liquids of medium degree of contamination with impurities of light suspension;
• not strongly gassed liquids;
• mixtures of gas and liquid;
• aggressive liquids;
• liquid metals.

Positive displacement pumps are used to work with different types of liquid. This type of pump works on the principle of changing the volume of the chamber, which leads to the transfer of the energy of the engine into the energy of the substance. Such pumps are able to work with any media, however, care must be taken high level vibrations.

Dynamic pumps can also handle all types of liquids, however they are not self-priming. Depending on the design features pumps exist various ways processing of the transported liquid. For example, dynamic type peripheral pumps are not designed to handle contaminated fluids including abrasives. For such units, the liquid with impurities is destructive, leading to thinning of the pump walls.

Types of industrial pumps

Pumps are used in industry different types. The main types of pumps used in various enterprises:

• multistage;
• gear oil pumps;
• submersible chemical pumps;

Industrial pumps are used in various fields

• in light industry;
• in the chemical industry;
• in construction;
• in mechanical engineering;
• in the extraction of minerals.

The type and type of pump is selected depending on the needs of the enterprise, the properties and quality of the pumped liquid.

The most popular are deep pumps, as they are widely used for domestic and industrial purposes. They are easy to install when installing water supply and heating systems, they are used to draw water from wells, in heating systems.

The main types of pumps by type of input energy:

• pumps powered by mechanical energy;
• water jet pumps;
• pumps powered by compressed steam or gas.

Pumps powered by mechanical energy include piston, propeller, screw, centrifugal and rotary pumps. Despite the same principle of operation, these pumps are very different in design. Water jet pumps - elevators, ejectors, work by supplying fluid to the impeller blades.

Pumps for fire extinguishing systems

The main requirement for fire extinguishing pumps is high pressure water supply. The most commonly used are centrifugal pumps, as they allow you to quickly pump water due to centrifugal force. Important points when choosing a fire extinguishing pump are:

• pressure;
• wheel speed;
• suction height;
• volume of water moved.

Depending on the number of wheels with blades, pumps are single-stage and multi-stage. Multi-stage units allow you to create a higher pressure, which in turn affects the pressure and height of the fluid supplied. When installing fire extinguishing systems in buildings, it is worth considering that the equipment must be checked periodically, as stagnation can cause difficulties during start-up. Fire trucks are equipped with centrifugal pumps and auxiliary units. Auxiliary pumps fill the centrifugal pump housing with liquid and switch off automatically.

Oil and fuel pumps

Among the industrial types of pumps, oil and fuel devices installed on car and machine engines and internal combustion engines are distinguished.

Oil pumps provide a reduction in the friction force between the interacting parts of the engine. They are adjustable and unregulated. Car engines are equipped with rotary or gear pumps for pumping oil.

Fuel pumps are installed in cars without fail. They ensure the delivery of fuel from the tank to the combustion chamber. Depending on the design, fuel pumps are: mechanical and electrical.

Submersible pumps

Submersible pumps are used when working at a depth of more than eight meters. All types of submersible pumps have a cooling system, and are made of durable material that helps to avoid deformation under pressure. Submersible pumps are centrifugal and vibration. In pumps of the second type, the liquid is sucked in using a vibration or electromagnetic mechanism.

(5 ratings, average: 5,00 out of 5)

A pump is a machine for creating a flow of a liquid medium. By liquid medium is meant a dropping liquid, which may contain a solid or gas phase. The purpose of the pump can be defined as follows: to impart mechanical energy to the dropping liquid in order to ensure its movement through pipelines (channels) or to transfer energy through the liquid to drive various devices and mechanisms.

Pumps are one of the most common types of hydraulic machines. They differ in a variety of designs, which sometimes makes it difficult to classify them. The flow of the liquid medium in the pump is created as a result of force action on the liquid in the flow chamber or in the working chamber of the pump. According to the type of working chamber and its communication with the inlet and outlet of the pump, pumps are distinguished dynamic and voluminous.

The classification of pumps can be performed according to various classification criteria:

for dynamic pumps:
according to the type of forces acting on the liquid;
in the direction of movement of the liquid medium;
by type of withdrawal;
according to the design of the impeller, etc.

for positive displacement pumps:
by the nature of the movement of the working bodies;
by the nature of the movement of the driving link of the pump;
in the direction of fluid movement;
by type of working bodies;
by the type of transfer of movement to the working bodies, etc.

A dynamic pump is a pump in which the liquid medium moves under the influence of force on it in a chamber that is constantly in communication with the inlet and outlet of the pump.
Dynamic pumps include:
1) bladed - centrifugal and axial;
2) electromagnetic - conduction and induction;
3) friction - vortex, jet, screw, vibration, etc.

The figure shows the circuit centrifugal pump. The flow of liquid medium enters the suction pipe 1 in the axial direction, changes the direction of movement in the channels of the impeller 2 to radial. Under the force of the blades, the fluid flow increases the speed of the fluid and the pressure in the impeller. After passing through the impeller, the liquid enters the outlet 3. The inlet and outlet of the pump are constantly communicating with each other.

Rice. Scheme of a centrifugal pump: 1 - supply; 2 - impeller; 3 - branch; 4 - body

A volumetric pump is a pump in which the liquid medium moves by periodically changing the volume of the chamber occupied by it, which alternately communicates with the inlet and outlet of the pump.
Positive displacement pumps include:
1) reciprocating - piston, plunger, diaphragm;
2) vaned;
3) rotary - rotary-rotary, rotary-translational, rotary-rotary, etc.

The figure shows one of the typical volumetric pump circuits - gear pump. The pump consists of two gears in mesh. The gears are in the pump housing with small clearances. One of the gears is driving, the other is driven. When the gears rotate, the volume of liquid enters between the teeth of the gears, is isolated from the suction and pressure lines, and then is forced out by the teeth into the pressure line.

Rice. Gear pump diagram

Further classification according to the common features of dynamic and positive displacement pumps can be made:
in the direction of the axis of rotation or movement of the working bodies: horizontal pump, vertical pump;
according to the location of the working bodies: cantilever pump, monoblock pump;
according to the design of supports: with outriggers, with internal supports;
according to the location of the liquid inlet to the pump: with an axial inlet, with a side inlet;
by the number of steps: single-stage, two-stage, multi-stage;
by the number of threads: single-threaded, multi-threaded;
according to the design and type of the body connector: sectional, with an end connector, with an axial connector, double-case, with a protective case;
according to the location of the pump: submersible, borehole, with a transmission shaft;
according to the requirements of operation: adjustable, unregulated, dosing manual, reversible, reversible;
according to the suction conditions: self-priming, with an upstream stage, with an upstream impeller;
for interaction with environment: sealed, explosion-proof, low noise, low magnetic;
according to the need to maintain the temperature of the medium: heated, cooled;
at the place of installation: stationary, mobile, built-in;
by size: small, medium, large;
by power: micro, small, small, medium, large.

The current practice of classifying pumps differs from the above.
Pumps are named, for example, according to the branch of technology in which they are used: heat power pump, ship pump, nuclear industry pump, chemical pump, etc .;
or by the type of pumped liquid: for clean water, oil, petroleum, gasoline;
for the intended purpose: nutritional, mixing, dosing, etc.