Centrifugal pumps are the most common pumps in the world. Due to its design and stable operation, this type of pump has found wide application both for solving domestic problems and for basic technological processes in a wide variety of industries. This article will give Full description centrifugal pumps, describes how a centrifugal pump works, its classification and main areas of use.
The main element of a centrifugal pump is an impeller (impeller), located inside a volute casing (volute), which has blades directed towards reverse side relative to the rotation of the wheel itself. The impeller is mounted on a shaft, which is connected to the pump drive. When the unit starts operating, the impeller begins to rotate, and liquid flows through the suction pipe along the axis of rotation of the wheel.
Under the influence of centrifugal force, the liquid moves through the channels between the blades in the radial direction (from the center of the impeller to its periphery) into the spiral chamber of the pump housing, and then into the discharge pipe of the pump. At the periphery of the impeller there is a high pressure zone. In the center, the pressure is reduced, which ensures a constant supply of liquid to the pump.
Design of centrifugal pumps
A centrifugal pump consists of the following main parts:
- Suction pipe
- Discharge pipe
- Volute casing (pump flow part)
- Impeller (impeller)
- Shaft seal
- Crankcase pump
Classification of centrifugal pumps
Centrifugal pumps can be classified according to the design of their main elements, type of installation and purpose.
According to the location of the pump nozzles
- Pump "in-line" type. With this type of pump, the suction and discharge pipes are in line opposite each other. The pumped liquid passes through the pump. The pump is installed on straight sections of the pipeline.
- Cantilever pumps. The liquid enters the center of the impeller (impeller). The pipes are located at 90˚C relative to each other.
By number of pump stages
- A multistage pump has more than one series-connected impellers on its shaft. This type of pump is used to provide high pressure at a relatively low flow rate. The high pressure is created by the sum of the pressures generated by each individual wheel. The pumped liquid passes sequentially from one stage to another.
By shaft seal type
To protect against the pumped liquid getting into environment and the mechanical part of the centrifugal pump uses various sealing systems. Based on the type of system used, pumps can be divided into:
- Centrifugal pumps with gland seal (link to gland seal)
- Centrifugal pumps with mechanical seal (single or double) (reference to mechanical seal)
- Centrifugal pumps with magnetic coupling (link to magnetic coupling)
- Centrifugal pumps sealed with wet rotor (link to wet rotor)
- Centrifugal pumps with dynamic seal (link to dynamic seal)
According to the type of connection with the electric motor
Centrifugal pumps are also divided according to the type of connection between the hydraulic part of the pump and the electric motor. There are types:
- Pump with coupling. An elastic coupling is an element that allows you to connect the electric motor shaft and the shaft on which the impeller is mounted. For this purpose, both a conventional coupling and a coupling with an intermediate element are used. The use of an intermediate element allows you not to disconnect the electric motor when maintenance pump, for example when replacing a mechanical seal.
- Monoblock pump. For this type of pump, the impeller is mounted either directly on the elongated shaft of the electric motor, or a stationary permanent blind coupling is used to connect the motor shaft and the pump.
By purpose
Due to its design capabilities, the purpose of a centrifugal pump can be very different. According to this indicator, the following types of centrifugal pumps are distinguished:
- Drainage
- Borehole
- Fecal
- Slurry
- Food
- Sanitary
- Firefighters
- Self-priming
Material design of centrifugal pumps
Centrifugal pumps are used in almost all industries, pumping a wide variety of liquids, from water to highly aggressive and abrasive suspensions.
Therefore, the choice of materials for the main elements of centrifugal pumps is very wide and most often it is based on durability of this material to the properties of the pumped liquid (link to the chemical resistance table) and the operating conditions of the pump itself.
The following main materials can be distinguished:
Metal version
- Cast iron
- Bronze
- Carbon steel
- Stainless steel
- Duplex
- Super duplex
- Titanium
- Etc
Lined and plastic versions
When working with highly aggressive liquids, such as acids, the metal version cannot always provide the necessary corrosion protection. Or the use of super-resistant alloys can lead to a significant increase in the cost of the entire structure.
Therefore, the use of a variety of plastics has become widespread as the main material in contact with the medium in centrifugal pumps.
There are two main types:
- Lined pumps. Lining is the process of applying a plastic coating to a metal pump body. All elements in contact with the pumped medium are covered with a layer of polymer, which significantly increases the corrosion resistance of the entire flow path. Modern technologies provide excellent adhesion between the coating and the body, because during casting the polymer fills all cavities and gaps.
- Plastic centrifugal pumps. The main elements of the pump in contact with the medium are made of solid plastic processed on special machines.
Materials for lined and plastic pumps:
- PP - polypropylene
- PVDF - polyvinyldene fluoride
- PE – polyethylene
- PVC – polyvinyl chloride
- PFA – perfluoroalkoxyl
- PTFE – polytetrafluoroethylene
- ETFE – ethylene tetrafluoroethylene (Tefzel)
- FEP – fluoroethylenepropylene
O-ring materials
The following elastomers are most often used as sealing rings in centrifugal pumps:
- EPDM - Ethylene propylene rubber
- NBR - Nitrile Butadiene Rubber
- FPM/FKM/Viton – Fluorine rubber
- FFKM - Perfluorinated rubber
Advantages and disadvantages of centrifugal pumps
Advantages:
- Simple design
- Few moving parts, long service life
- High efficiency
- High performance indicators
- Constant flow, no pulsation
- Capacity adjustment via discharge throttle valve or frequency converter
Flaws
- Impossibility of “self-priming”
- High risk of cavitation
- Productivity is highly dependent on pressure
- Most effective at only one given operating point. When regulating the supply using a frequency converter, efficiency decreases
- Cannot handle multiphase fluids containing air or gas
- When pumping abrasive liquids, rapid wear of the main elements is possible due to high speed rotation of the impeller (about 1500 rpm).
- Cannot handle highly viscous liquids (max. 150 cSt)
Areas of use
Centrifugal pumps are used in almost all industries.
The main ones:
Water supply and sanitation
Water treatment plants
Energy
Oil and gas industry
Chemical industry
Pulp and paper industry
Mining industry
Pharmaceutical
Main manufacturers
The major players in the centrifugal pump market can also be broken down by the industries in which they are strongest:
Water supply, drainage, water treatment
- Grundfos: grundfos.com
- Wilo:wilo.ru
- Xylem Group of Companies. Pumps Lowara, Goulds, Flygt, Vogel, etc.: http://xylem.ru
- KSB: https://www.ksb.com/ksb-ru/
- Pentair: www.pentair.com
- Ebara: http://www.ebaraeurope.ru/
- Caprari: www.caprari.it
Petrochemical industry
- Flowserve www.flowserve.com
- ITT www.itt.com/
- Sulzer www.sulzer.com
- Hermetic Pumpen www.hermetic-pumpen.com
- Kirloskar pumps www.kirloskarpumps.com/
- Ruhrpumpen www.ruhrpumpen.com
Chemical industry
- Munsch munsch.de/
- Pompe Travaini www.pompetravaini.it/
- Someflu pump www.someflu.com/
- Rutschi Gruppe www.grupperutschi.com
Mining industry
- Warman. Weir Mineral Group https://www.global.weir/brands/
- Krebs. flsSmidt Group http://www.flsmidth.com/en-US/Krebs
- Habermann pumpen www.aurumpumpen.de/ru/
All exploited pumping devices are intended for interaction with liquid and differ in the nature of the effect of functional components on water.
All pumps are divided into 2 main categories:
- Dynamic.
- Volumetric.
In dynamic devices, liquid is pumped under the action of forces interacting with water in the working cavities between the inlet and outlet of the device. Centrifugal pumps are considered typical representatives of this category. Detailed description The classification of such devices is given in this article.
Types of centrifugal pumps
The main functional component of each centrifugal pump is a wheel with blades located on a special shaft in a spiral-shaped housing. Such a pump operates due to the action of centrifugal force. The liquid enters the working housing in the axial direction. When the blades rotate, water is pressed against the walls of the housing and then comes out under pressure through the discharge hole. At the point where water enters the pump, the pressure level decreases, and in the area of the impeller it increases. Basic functional feature Centrifugal pumps are capable of continuous water supply.
There are the following types of centrifugal pumps:
- Single-stage horizontal. Design features determine the name of these cantilever mechanisms, in which the impeller is mounted on the tip of the shaft. In this situation, the shaft acts as a console, at a distance between the front bearing and the wheel. The pump is fixed on the base plate, which also holds the electric motor;
- Multi-stage horizontal. These devices have several impellers on one shaft. The functional characteristics of such devices are comparable to several pumps installed on one water supply system. The main task of such pumps is to generate high pressure with relatively small water supplies. Such devices create a pressure approximately corresponding to the combined pressure of the water flow in the system by several devices;
- Fecal pumps are used to interact with liquids containing a large number of different impurities. Supply working fluid performed in the axial direction. In everyday life and industry, vertical and horizontal devices. The main distinguishing feature of such devices is the relatively a small amount of blades on the wheel. The body of the fecal pump is equipped with special hatches necessary for servicing the device.
- Dredgers and sand devices are used to interact with industrial wastewater containing many different impurities. Such pump models facilitate pumping hydraulic fluid with a normal volumetric mass of 3 kg/l.
Separately, we should consider centrifugal pumps for extracting water from wells.
Operating principle
The channels between the blades are filled with water during the operation of the centrifugal pump. When the shaft rotates, the water located between the blades is affected by a centrifugal force, which promotes the removal of liquid from under the working stage. Thus, a vacuum may occur in the center of the stage, accompanied by an increase in pressure at the periphery. Water is pumped through the suction pipe and then through the pipe into the pump.
The working fluid moves through the pipeline due to the difference in pressure in the central part of the wheel and the receiving container used. Water under pressure is discharged from the impeller, directed into the volute chamber, and then enters the pressure pipe, through which it flows into the pressure pipe. The centrifugal force indicator increases significantly with increasing shaft speed, therefore, the pressure in the system increases. A conventional electric motor or turbine can be used as a driving drive for centrifugal pumps.
Today, such devices are used in the most different areas activities. There are many subcategories of centrifugal pumps that are in considerable demand in the domestic market.
Downhole centrifugal pumps
Downhole pumping devices are divided into two main subcategories:
- Semi-submersible.
- Submersible.
Semi-submersible units often have a multi-stage design with an installed pressure pipeline, an electric motor and a reliable support unit. Elastic rubber or lignofolic bearings are mounted in the equipped crosspieces of the pressure pipe used, thanks to which the pump shaft can rotate normally. Several shaft sections are combined using screwed couplings. Thanks to chrome plating, the shaft walls are reliably protected from corrosion and their wear resistance increases. The counter-reverse mechanism blocks possible rotation of the shaft in the opposite direction. Impellers in devices are of open or closed type. Mechanisms with open wheels are significantly less sensitive to all kinds of impurities. However, pumps with closed wheels significantly increase efficiency. The pressure pipeline in the semi-submersible devices used is assembled from several sections.
The electric motor can be serviced without special labor in semi-submersible systems. However, the installation of such systems requires compliance with certain rules during the process of drilling a well, which must be vertical and straight. Also to distinctive features Such equipment is characterized by high metal consumption and installation complexity.
The submersible pump, lowered into the well, is equipped with an electric motor and a multi-stage water intake system. The device is immersed in the installed casing pipe and fixed to the pressure pipe structure using a special coupling. Weight pumping unit transmitted to the base plate through a pipeline consisting of several sections. It is connected to the pressure pipeline using special clamps electrical cable, feeding the engine. The operating device is controlled using a remote automated system.
Compared to semi-submersible systems, submersible systems have insignificant metal consumption, their installation can be carried out in non-linear boreholes, installation and dismantling is much simpler. The disadvantages of such devices include a high sensitivity to the presence of sand mass in the pumped water.
Advantages and disadvantages of centrifugal pumps
Centrifugal pumps are endowed with many advantages, thanks to which they are widely popular in the domestic market.
These advantages include:
- Relatively large number of shaft revolutions. This makes it possible to use electric motors and turbines as mechanisms that provide rotation;
- Possibility of gradually reducing or increasing power. Thanks to this quality, the device can be started with the valve at the outlet closed;
- When several pumps are installed on one pipeline, the pressure level and intensity of water supply increase significantly;
- Simplicity of design;
- Comparatively cheap;
- Possibility of using an automated control system;
- Liquid can be drawn into the pump from a great height;
- The efficiency of such devices is approximately 0.6-0.8;
- Reliability of operation.
The disadvantages of this class of pumps include:
- The likelihood of unstable water supply, changing in the event of unstable operation of the electrical circuit.
- When starting, the working tank of the centrifugal pump must be filled with water. Often water has to be poured into the device if the liquid level does not reach the inlet pipe.
- The functional characteristics of the mechanism can be significantly reduced in a situation where air mass enters the spiral, causing bearings and other components to fail faster.
To ensure that air is safely removed from the system, special plungers are installed on the casing.
You need to understand that the functional characteristics of pumps are influenced by several factors:
- The occurrence of blockages in the suction area. To do this, replace the filter;
- Excess permissible level temperature of the pumped water. In this case, you need to turn off the pump and wait until the liquid cools down;
- The diameter of the pipeline is too small in relation to its length. System design flaws that require adjustments;
- Depressurization of joints on shut-off valves, as well as installed flanges. In such cases, the cause of the depressurization is found and appropriate sealing measures are taken.
Self-installation of a centrifugal pump is not difficult. You must always understand what difficulties may arise during operation. It is necessary to constantly monitor the operation of the device to avoid problems in the future. When the first characteristic features violation of the stability of the supply of working fluid, you need to independently identify the problem that has arisen. If taken in a timely manner necessary measures, you will be able to use the pump longer without the need for repair work.
Pump classification
In the “About the Site” section we will talk about the classification of pumping equipment. Pumping equipment is widely used in various fields industry and everyday life, based on this, pumping equipment manufacturing plants are constantly expanding and improving their range, developing and offering to the market new types of pumps for various functional purposes and technical characteristics. The main parameters of any pump, regardless of its type or type, are flow and pressure. Flow is the volume of pumped medium per unit of time. It is measured in cubic meters per hour (m3/hour). Pressure is maximum pressure that a pump can create on a discharge pipe. The pressure is measured in meters of water column (m). Very important characteristics of pumping equipment are also its effective power factor (efficiency) and power consumption (kW). Like any equipment, pumping equipment also has its own technical parameters that determine its class, type and, ultimately, its cost.
This classification will not be complete, since today there are many other ways to classify pumping equipment. We will look at the most commonly used classification methods.
Types of classification
pumping equipment
As you know, pumping equipment consists directly of the pump itself and the drive. At the moment, in the CIS countries there is no unified interstate system for classifying and coding pumping equipment. In the Unified System of Design Documentation (ESKD), class 6 provides for the classification of pumping equipment according to design and consumer characteristics. GOST 17398-72 “PUMPS terms and definitions”, which is currently in force in Russia and other CIS countries, establishes terms and definitions for pumping equipment and their main technical indicators and characteristics. This standard, in a recommendatory manner, defines the types of pumps by design features, and also, in a recommendatory manner, includes a scheme for classifying pumps by type, by principle of operation and by design.
Due to the fact that there is no unified system for classifying pumping equipment and spare parts, traditionally, pumping equipment manufacturing plants have developed the most various ways their classifications. As an example, we can highlight the classification of centrifugal pumps:
By functional purpose depending on the operating methods: (make-up, condensate, circulation, network, ship, etc.);
by type of pumped medium (water, oil, chemical, etc.);
by the number of impellers (one-stage, two-stage and multi-stage pumps):
according to the location of the shaft axis in space (horizontal and vertical):
by pressure (pumps for low pressure, middle and high pressure);
according to the method of supplying liquid to the impeller (with one-way or two-way (double suction));
according to the method of connection to the drive (with a gearbox, with a pulley or connection using a coupling):
according to the method of installing the pump relative to the surface of the liquid (surface and submersible).
In GOST 17398-72 “PUMPS terms and definitions” you can find definitions of the types of pumps used:
A pump is a product used to create a flow of liquid. The pump is driven using drives.
Centrifugal is vane pump, in which fluid moves through the impeller from its center to its periphery. This type pumping equipment are the most common type of dynamic machines. They are very widely used: in water supply, heat supply, sewerage, chemical, nuclear, and aviation industries.
is a pump in which liquid moves along the periphery of the impeller in a tangential direction. Vortex pumps are similar in design to centrifugal pumps. The body of the product is sealed; inside the body there is a shaft with an impeller fixed on it. The wheel has blades mounted perpendicular to the axis of rotation of the shaft, transmitting fluids mechanical energy. As a result, the pumped liquid enters the sockets and is transferred to the pressure pipe of the pump.
- this is a pump in which the shaft with the impeller (wheels) is located horizontally, regardless of the location of the drive shaft or transmission.
- this is a pump in which the shaft with the impeller (wheels) is located vertically, regardless of the location of the drive axis or transmission. Horizontal and vertical pumps used in water pressure boosting installations for industrial, urban or rural water supply, in automatic pumping stations, as well as in irrigation and field irrigation systems.
a pump is a pump whose working elements are located on the cantilever part of its shaft. This type of centrifugal pump with a one-way supply of liquid to the impeller located at the end of the shaft (console) installed in the bearings of the pump housing, remote from the drive. The products are equipped with a drive installed, as a rule, on a common platform. Cantilever pumps are used for pumping water, chemically non-aggressive liquids, and liquids containing impurities.
is a pump in which the impeller (wheels) are located on the drive shaft (motor). This type of centrifugal pump is characterized by an axial suction pipe and a radial discharge pipe. The liquid enters the pump in a direction coinciding with the longitudinal axis of the shaft, and is discharged (supplied) perpendicularly (radially) to it. This type of pump has a fairly wide range of uses, from water in water supply and fire extinguishing systems to ensuring coolant circulation in heating and air conditioning systems.
A side entry pump is a pump to which fluid is supplied in a direction perpendicular to the axis of the impellers.
An axial inlet pump is a pump in which the liquid is supplied in the direction of the axis of the impellers.
Single-stage is a pump in which the liquid is moved by one set of impellers. Due to their high reliability and ease of operation, as well as silent operation and the absence of the need for regular maintenance, these pumps have found wide application in industry and households. Maximum depth suction of such pumps is 7 meters
A two-stage pump is a pump in which liquid is moved sequentially by two sets of impellers.
Multistage is a pump in which liquid is moved sequentially by several sets of impellers. A multistage centrifugal pump differs from a conventional centrifugal pump in the number of impellers: three or more, mounted on one shaft. The wheels rotate inside diffusers, which ensure that fluid moves from the outlet of each impeller towards the suction pipe of the subsequent impeller. After the liquid passes through all successively installed impellers, it is pushed out of the pump through the pressure pipe.
A surface pump is a pump that is mounted above the level of the pumped liquid. This pumping equipment is installed near a water supply source. Liquid is collected using the suction method. This type of pump has certain restrictions on the depth of suction of liquid from the water supply source. The suction depth is 8-9 meters. For large suction depths, it is necessary to install pumps either with a remote ejector or submersible pumps.
A submersible pump is a pump that is mounted below the level of the pumped liquid. This type of pumping equipment is installed in cases where the use of a surface pump is either impractical or impossible. This equipment is immersed directly into the pumped liquid. Submersible pumps are designed to supply liquid from deep wells, pits, open reservoirs, where the depth distance is more than 9 m
- This is one of the types of submersible pumps that are installed in wells.
A dosing pump is a pump that supplies a liquid or chemical solution with a specified accuracy.
A manual pump is a pump in which the movement of fluid is carried out by human muscle power.
is a pump that allows you to independently fill the supply pipeline with the pumped liquid.
- This is a pump in which the ejector is mounted in a well or deep well. The pump itself is located on the surface. Two pipes connect from the ejector to the pump, through which the pumped liquid is supplied and recirculated.
Explosion-proof is a pump whose design ensures explosion-proof operation under specified conditions.
An electric pump is a pump driven by electric motor, the structural components of which are included in the design of the pump
Lack of a single and systematic approach to the classification of pumping equipment in the CIS countries has led to the emergence of a significant variety of their types. Pumping equipment is similar or even the same type in terms of parameters, design and functional purpose - it is practically not unified and is produced according to various design and technological documentation, including according to its own standards. In pumps that belong to the same design, repeatability engineering solutions practically absent, not to mention the unification of spare parts and components in pumping equipment of various design, for example, vertical and horizontal. The imperfection of methods for classifying pumping equipment and spare parts for them, as well as the lack of leverage that would be aimed at ensuring a level of unification and standardization of products during design and production, has led to the fact that the development and modernization of pumps is carried out in isolation from unified internationally recognized foreign ones. products.
The “EUROPUMP” classification system is based on the German national standard VD MA 24261 “Classification of centrifugal, (part 1) positive displacement plunger (part 2) and rotary pumps” (part 3), as well as the main provisions of the standard used in the development of classification systems in national US standards, such as API610. This classification system for pumping equipment allows them to be classified into classes and groups based on the main functional and design features with a gradual transition to secondary features. These principles for classifying pumping equipment are used in leading EU countries, and are also recognized by the vast majority of foreign countries where pumping equipment is produced. Naming and coding standards "EUROPUMP". DIN 24250 “Centrifugal pumps, product names and numbering”, DIN 676 “Classification. Coding. Basic concepts”, which were developed on the basis of the European system, the International “Harmonized System for Description and Coding of Goods”, are consistent with each other and contribute to the establishment of unification of terms, definitions and names.
In conclusion, it should be noted that such work should be carried out in the Interstate Council (ISC) for standardization, metrology and certification of the CIS on the implementation of international standards and publications “EUROPUMP” in Russia and the CIS countries.
The blowers that have become widespread in water supply and sanitation include:
1. vane pumps: centrifugal, diagonal, axial, vortex;
2. piston pumps
3. rotary blowers (screw, gear)
4. air water lifts
5. jet pumps (superchargers)
6. compressors.
The most widespread are - centrifugal pumps.
The principle of operation of the pump is easy to understand from Fig. 1.
A centrifugal pump is not a sealed machine.
To ensure the tightness of the pump, it is filled with water. (various filling methods: from a water supply, a vacuum pump, from a pressure tank).
When the impeller rotates, the liquid filling the impeller also begins to rotate, thereby acquiring centrifugal force. Under the influence of these forces, liquid particles rush from the center to the periphery along the radius. The greater the radius of the wheel R and the frequency of its rotation n, the greater the speed of fluid movement, the higher the speed of fluid particles rushing to the pressure pipe of the pump. The volume filled with liquid is emptied and a reduced pressure is created in it - a vacuum. Under the influence of atmospheric forces, water from the supply tank flows through the suction pipe onto the wheel blades into a zone of low pressure. And the cycle repeats.
The pump body has a snail shape and serves to convert the kinetic energy of the liquid into potential energy (the housing expansion zone), as well as to dampen transverse forces (axial forces and transverse or radial forces).
Piston pump.
The piston pump is a sealed machine and therefore does not require priming. It can pump both liquids and gases (Positive displacement pumps).
Main structural elements of the pump:
Rotary blowers include pumps that, like piston ones, move liquid by displacing it. Only in a piston pump the working element has a reciprocating motion, while in rotary pumps the working elements rotate in a circle and there are more of these elements than the number of pistons.
An example of a rotary supercharger is a gear pump:
Due to the hermetically sealed pinching of the gear teeth with each other, the working chamber of the pump is divided into two parts: suction and pressure. In the suction chamber, the teeth alternately displace the medium located there (oils, liquids). Thus creating a vacuum, and in the pressure part they create excess pressure due to the flow of the displaced medium.
Screw pumps (one leading and two driven screws) and a vane pump operate on approximately the same principle.
Vortex pump.
The operating principle of vortex pumps is also based on the transfer of energy from the blade to the fluid flow.
1 – impeller with radial blades. 2 – ring channel
6ºA – window in the side of the body.
The liquid enters the impeller blades through window A. The impeller is a kind of centrifugal wheel with radial blades. Around the periphery of the wheel in the pump body there is an annular channel ending in a pressure pipe. The area of the inlet channels is separated from the pressure pipe by a section that fits tightly to the wheel (radial clearance) of no more than 0.2 mm and serves as a seal.
The liquid entering the pump through the inlet hole enters the inter-blade spaces, in which mechanical energy is imparted to it. Centrifugal forces throw it out of the wheel. In the annular channel, the liquid moves along helical trajectories and after a certain distance again enters the inter-blade space, where it again receives an increase in mechanical energy.
Thus, a kind of annular vortex motion is formed in the body of the operating pump, from which the pump received the name vortex. The multiplicity of energy increments of liquid particles leads to the fact that vortex pump all other things being equal, it creates significantly greater pressure than centrifugal pressure. The presence of a sealing section allows the pump to pump gases.
Disadvantage – low efficiency – 40-50%
There are two types of aerial water lifts:
Displacers (montju, pulsometers, jats, Kremer superchargers)
Airlifts.
Displacers used to move contaminated or aggressive liquids. They consist of: a receiver - where the liquid is supplied, a compressor, a discharge pipe, which is connected to the upper part of the receiver.
Under the action of compressed air, the liquid is forced through the pressure pipe to the desired height.
Airlifts – are used to extract water from deep tube wells.
Rice. 2. Air lift
a-diagram of the device; - b-pressure characteristic; /-receiving tank; 2-air pipe from the compressor; 3-water pipe; 4-casing well; 5-nozzle
The water-lifting pipe (3) is lowered below the water level into the well. The air pipe (2) supplies compressed air from the compressor to the bottom of the water rise pipe using a perforated air distributor (5). Compressed air, dissolving in water, saturates the water. Due to this, the specific gravity of the water-air mixture inside the water-lifting pipe is less than specific gravity water in the well. By adjusting the amount of air supplied, you can ensure that the water-air mixture begins to rise through the pipe and pour into the container.
Disadvantage – low efficiency – 20-30%
Jet water lifts work on the principle of using energy working environment to move liquid.
The working medium can be: water, steam, gas.
If gas, then an ejector. Water – hydraulic elevator
Rice. 3. Water jet pump
A -device diagram: /-suction pipeline; 2 -pipe; 3 -nozzle; 4 - supply chamber; 5 -mixing chamber; 6 -diffuser; 7-pressure pipeline; b-theoretical flow-pressure characteristic
In water jet - hydraulic elevators - the working fluid (water) under high pressure h flows through pipe 2 into the nozzle, and from it into the narrowing part of the pipe - 4, where the speed of the fluid increases due to the energy of the working fluid. As the speed increases, the pressure drops in section 1-1 and a flow of liquid from the reservoir rushes to this place under the influence of atmospheric pressure.
Disadvantage: low efficiency.
A hydraulic device that is used to suck in, move or pump water is called a pump. As a rule, any movement of liquid by such units occurs due to the transfer of potential or kinetic energy to it. Depending on the technical parameters and there are appointments different types pumps At the same time, they differ in efficiency, power, volumes of liquid pumped per unit of time, maximum pressure and pressure created.
The choice of the type of pumping equipment depending on the purpose of use can be made based on the following classification:
- All submersible pumps can be divided into three groups:
- borehole type units are suitable for installation in wells;
- drainage equipment is divided, in turn, into two types: pumps that work with clean water, and devices that can be used to pump dirty water;
- well units are installed in mine wells.
- All surface pumps can be divided into the following types:
- fountain;
- sewerage installations, which are divided into units for external and internal use;
- pumping stations.
It’s worth knowing: there are about 3 thousand types of units for pumping water. Their design principle, scope of application and power supply features may differ significantly. To make the right choice, it is necessary to take into account the purpose of the device and operating conditions.
Classification
When choosing pumping equipment, it is very important to consider the type of power supply, since in some conditions the unit may need to operate independently from the mains. This type of operation is typical only for units equipped with an internal combustion engine.
So, according to the type of power supply, all pumps can be divided into the following types:
- Electrical devices used to operate the motor alternating current. This makes them dependent on the power grid. However, this allows you not to worry about replenishing fuel supplies. The choice of such a pump should be made if there is a working electrical network at the place of its use. It is important to take into account the voltage in the network, as well as how many phases the device is designed for.
- Liquid fuel pumps, called motor pumps, run on internal combustion engines. They are divided into the following types:
- Gasoline. These units use a gasoline-oil mixture prepared in a certain proportion. They are quieter to operate and less expensive than diesel units.
- Diesel pumps run on diesel fuel. These devices are characterized by high efficiency and increased noise during operation.
The main advantage of motor pumps is their mobility and ease of use. They are suitable for places where there are power outages or no electrical networks at all.
There is also a classification of water pumps depending on the purity of the pumped liquid. According to this criterion, pumping units are divided into the following types:
- For clean water with a content of solid impurities not exceeding 150 g/m³. This includes borehole, well and all modifications of surface pumps;
- for medium polluted water, in which the impurity content does not exceed 200 g/m³. This category includes drainage pumps, self-priming and circulation units, some types of pumping stations and fountain pumps;
- for heavily polluted water with a concentration of solid impurities greater than 200 g per cubic meter. This category includes some types of sump pumps as well as surface sewer devices.
Attention: incorrect selection of a pump based on the purity of the pumped liquid can lead to rapid wear of mechanical parts and failure. You can independently assess the degree of purity of water only by the amount of sediment and floating solid particles.
Based on their location relative to the water surface, all pumping units are divided into the following types:
- Surface pumps are installed at some distance from the source and communicate with it through a pipeline or hose. The power of the unit depends on the distance at which it is located from the source. The larger it is, the higher the power should be.
- Submersible units mounted in hydraulic structure. In this case, the body of the device must be completely or partially immersed in water.
Surface type units
Surface type pumps are most often used in everyday life for dachas, country houses and cottages. They are suitable for irrigation system, watering the garden and raising the pressure in the water supply system.
These water pumps are small in size, easy to operate and highly economical. If they are equipped with additional automation, the devices will operate as autonomous pumping stations. And when equipped with a remote ejector, the unit will be able to lift water from a considerable depth.
According to the method of transporting water and the design, such devices are divided into the following types:
- Vortex units are units with a special shape of impeller blades, which promotes the characteristic rotation of water in the space between the blades. Thanks to the concentration of turbulence in one channel, it is possible to achieve a powerful rotational movement of the flow. As a result, the pressure of such a unit is 5 times higher than that of its centrifugal counterpart. These are compact devices with an affordable price. However, they can only work with clean aqueous media.
- Centrifugal pumps have blades that disperse water along the walls of the working chamber. These are more massive units with silent operation.
Self-priming devices
These types of pumps are highly valued for their simplicity, ease of maintenance and ease of use. Depending on the presence of an ejector device, the units are:
- ejectorless. Liquid is drawn into them due to the special hydraulic design of pumping equipment;
- ejector In this device, water is raised by pumping a vacuum in the ejector.
Such equipment can be used for:
- watering the garden and garden;
- ensuring drinking and domestic water supply to a country house;
- for lifting liquid from clean or slightly polluted surface reservoirs, wells or boreholes.
The main disadvantage of ejectorless units is low height lift not exceeding 9 m. However, units with an ejector can easily cope with this problem. Self-priming pumps difficult to operate in the cold season, since all water supply mechanisms are on the surface and need protection from freezing.
Fountain pumps
The fountain type of pumping equipment has found wide application in landscape design. With the help of such units, mini ponds are built, decorative ponds, streams, fountains and cascading waterfalls. Selected models Such equipment is supplemented with a liquid filtration function, so they can work with sea water.
Thanks to the use of special nozzles, you can create beautiful fountain jets. In addition, such pumping equipment can be used for irrigation of individual nearby areas.
Fountain pumps are divided into two types:
- devices installed on the bottom of the reservoir (only the nozzle is visible on the surface);
- units installed outside the water source.
In addition, there are heavy-duty units for creating large-scale water compositions and servicing objects of significant size, as well as low-power equipment for small reservoirs and fountain ensembles.
Pumping station
The unit consists of the following parts:
- pump;
- hydraulic accumulator;
- check valve;
- control sensors.
The operating principle of the equipment is based on the structure of a hydraulic tank, inside of which there is a rubber bulb into which water is pumped from a source. This bulb is placed in a steel case into which air is pumped, creating a certain pressure in the system. The pressure switch responds to changes in air pressure, which depends on the degree of filling of the bulb with water. As a result, the relay starts or stops the pumping equipment to pump water into the tank.
Important: To extend the life of the pump, be sure to use a filter device on the suction pipe.
Submersible units
These devices are installed at the point of water intake. In this case, either the entire unit with the motor is immersed in the aquatic environment, or the electric motor is located above the surface of the water. Such pumping equipment can pump liquid from significant depths. It features high performance and efficient engine cooling.
Depending on the internal structure The device is divided into the following types:
- vibration pumps- these are devices that absorb liquid due to an electromagnetic field and a vibration mechanism. This operation of the device dictates special rules for its installation - at a certain distance from the bottom of the water intake, since the unit is capable of lifting silt, sand and other sediment from the bottom;
- centrifugal units work due to the torsion of the blades. When water hits them, it is thrown onto the walls of the working chamber and transported out under pressure.
Well pumps
These units are suitable for lifting water from the bottom of wells. These devices have an elongated cylindrical configuration and small sizes allowing them to be lowered into the casing. Such equipment can operate at considerable depth in artesian wells. The power of the device is quite impressive. Only slightly polluted or clean water media are suitable for pumping.
Tip: when choosing the diameter of the pump, make sure that its size is 1-1.5 cm smaller than the cross-section of the casing pipe, since a cable attached to a loop of the casing is used to freely remove the device.
Drainage equipment
This equipment is suitable for pumping contaminated water from reservoirs, flooded basements, pits, trenches, etc. However, there are also modifications that are designed to work in lightly polluted environments.
The drainage pump can easily handle water that contains large amounts of sand, grass, clay, silt or other small debris. And some models are equipped with grinding knives, similar to fecal pumps. The pumped water can be used for irrigation, watering the garden and technical needs.
Well units
Such pumps are suitable for pumping water from mine wells. The aquatic environment may contain small amounts of small impurities in the form of sand, clay and silt. Their main difference from borehole type units is their immersion depth, which is relatively small. Such equipment is suitable for pumping clean water for drinking water supply needs.
The power, maximum pressure and productivity of such equipment are quite impressive, but the dimensions of the device are not compact in size. Well-type units boast silent operation and low vibration.
Circulation pumps
These units are installed in water supply and heating systems and promote the circulation of liquid in them. Typically these devices have a cast iron, bronze or steel body. Water circulation occurs due to the rotation of the impeller on the rotor.
Depending on the method of cooling the rotor, circulation-type units are divided into the following subtypes:
- Devices with wet rotor mounted in the pumped liquid. The motor is cooled by the transported water medium. These are unpretentious, silent devices with smooth speed control and an affordable price.
- Dry rotor pumps. This device uses special oil for lubrication and cooling. At the same time, the motor does not come into contact with water during operation. These devices are suitable for transporting large volumes of water because they have a higher efficiency (up to 80%). However, the unit requires regular maintenance, which consists of changing the oil for lubrication and cooling.
Such pumps ensure the movement of coolant in the pipeline and are suitable for heating and hot water systems. They can be used in small country houses, and in large country houses. The choice of unit is made based on the length of the pipeline and the volume of the heated room.
Sewage pumping devices
Such equipment is used to drain Wastewater. Depending on the installation location, pumps can be of two types:
- Submersible drainage units of sewer type are installed in the place where wastewater is collected, namely in a septic tank, septic tank, drainage ditch, cesspool and so on. The flow of wastewater into these storage tanks is carried out by gravity due to the inclination of the pipes. Typically, such equipment is used in summer cottages.
- Forced sewage pumps external type is a combination of pumping equipment and storage tank. This device is installed in multi-storey buildings, office buildings, production premises where it is not possible to remove wastewater by gravity. They are mounted at a suitable lower point of the system and collect wastewater into a special tank, from where, under the action of a pump, it is delivered to the point of independent drainage into the sewer system.
As a rule, many sewage sewage pumps are equipped with special grinding knives. This allows them to transport highly contaminated wastewater. Thanks to the knives, large waste components are crushed, which prevents clogging of the pumping equipment.
