Screw screw pumps have a wide range of applications due to their design features, ability to pump dissimilar liquids and other significant advantages over other types of pumps.

Screw screw pump and its features

Such features of a screw screw pump as a valveless design, the ability to change the direction of flow of the pumped type of liquid and the direct dependence of performance on the number of engine revolutions allow this species pumps carry out pumping of various types of liquids. The list of liquids that a screw screw pump can pump is constantly growing. The rotor-stator pair plays the role of the main working part of a pump of this type. The metal rotor is made in the form of a screw and is located inside the cage, that is, the stator. When the rotor rotates, the volume of the cavities inside this pair changes, therefore, the liquid begins to move along the axis of the pump itself through displacement due to the rotation of the rotor. In this case, a suction effect is created in the cavities by changing the volume.

What liquids can a screw pump handle?

Capable of pumping dissimilar liquids that have different characteristics. It is capable of pumping abrasive, emulsion, heterogeneous liquids, as well as liquids containing solid particles. The viscosity of the pumped liquids can reach a million centipoise, and the temperature can reach nine hundred degrees in continuous operation and 1200 degrees in intermittent operation.

Where are screw pumps used?

Screw screw pump can be used in various types industry. In heavy industry, these pumps are used to pump anti-corrosion agents and siliceous suspensions. Latex, paints, and silicones are also pumped. IN Food Industry fermentation wort, honey or vegetable pulp, juices, fats, etc. are pumped. When processing milk, milk, condensed milk, sour cream and yogurt, processed cheeses, etc. are pumped. Screw pumps are also widely used in the cosmetics industry when pumping creams, oils and various cosmetic solutions, as well as liquid soap and shampoos. Screw pumps found wide application and in construction for pumping groundwater, transporting river water containing sand. Similar pumps are also used for water purification. Pumps are used to dose the supply of flocculants, polymers, polyelectrolytes, demineralized water and various chemicals.

Based on materials from optovik.net

A screw pump, also called a screw pump, is one of the types of rotary-gear type devices. In it, the pressure of the injected liquid is formed due to its displacement by screw rotors rotating inside the stator. There may be one or more of them, depending on the device configuration. Screw pumps are easily obtained from gear pumps, and this is done by increasing the inclination of the teeth in them, as well as reducing the number of teeth on the gears. However, it is better to use " original version" devices.

The screw pump operates according to the following principle. Pumping of liquid is carried out due to the fact that it moves between the screw grooves and the surfaces of the housing. The grooves are located along the axis of the screw. With their protrusions they “walk” along the replaceable grooves, which prevents the fluid from moving backwards.

The screw pump is used in a fairly wide range. It can be useful for pumping gas, steam, as well as their mixtures or liquids with varying degrees of viscosity. They were first introduced into production back in 1936. Due to the simplicity of their design, they can operate freely even in the presence of mechanical impurities containing viscous fluids at a pressure level of up to 30 MPa. Such characteristics are very important for solving a wide variety of problems. Entire installations are actively used in wells designed to extract methane from coal seams, as well as to pump water from there. They are used for water, as well as for other wells.

The screw pump has interesting design features. To increase the quality of seals, as well as to reduce the number of leaks in this type of device, it is customary to use cylindrical or conical elastic bodies. The conical screw is pressed very reliably by the spring; in addition, the pressure of the pumped liquid plays a role here, which significantly reduces the number of leaks. Pumps having metal case, are able to withstand significantly higher loads than their counterparts placed in elastic housings. A device with a conical screw can work well in a rigid case.

The most common screw pump is a three-screw pump. In practice, its scope of application turned out to be the widest. This is due to certain characteristic advantages of this type of equipment:

Uniform supply of substance;

Possibility of pumping liquids containing solid additives without any damage;

Possibility for self-priming of liquids;

High outlet pressure can be obtained without the mass of injection cascades characteristic of other;

During operation, the device creates noise effects at a fairly low level;

The pump mechanism is very well balanced.

This type also has certain disadvantages, which are significantly less than the advantages:

Enough high degree difficulties in the manufacture of this type of equipment, as well as its high price;

Lack of ability to regulate working volume;

Idle use is simply unacceptable.

Purpose and technical characteristics

Installations of submersible screw twin electric pumps are designed for the production of oil, mainly of high viscosity and gas content.

Currently, the domestic industry produces electric submersible screw pumps for oil production of the following parametric series:

UEVN5-12-1200

UEVN5-12-1500

UEVN5-16-1200

UEVN5-16-1500

UEVN5-25-1000

UEVN5-25-1500

UEVN5-63-1200

UEVN5-100-1000

UEVN5-100-1200

UEVN5-200-900.

Installation applicability indicators:

Maximum kinematic viscosity, m 2 /s - 1*10-3

Maximum content of produced water,% - 99

Maximum content of free gas at the pump intake, % by volume - 50

Maximum mass concentration of solid particles, g/l - 0.8

Microhardness of particles, HRC no more than - 55

Maximum temperature, °C - 110.

Screw pumps are characterized by basic hydraulic parameters: head, pressure, power, efficiency.

In the tables below. 2 and 3 are presented specifications installations of electric submersible screw pumps and the pumps themselves.

Operating principle of a screw pump

In a positive displacement pump, the working process is based on the displacement of liquid from a working chamber, hermetically separated from the suction and discharge cavity. Pumps of this type have greater rigidity of characteristics when changing parameters, the ability to pump small volumes of liquids at high pressures, as well as liquids with a wide range of viscosity values ​​and liquids with a gas component.

Reliability and durability of operation under given conditions are one of the decisive factors when choosing the type of pump.

A distinctive feature of a single-screw pump as a rotary-type pump is the presence of developed friction surfaces and places with a slot seal. Hence the conclusion is that ensuring a regime of liquid friction between the rotor and stator is a necessary and sufficient condition for a long pump life.

Let's consider the operating conditions of the pump at steady state (n=const).

The provision of fluid friction mode will be influenced by geometric parameters the helical surfaces of the rotor and stator and ultimately the gap between them, the properties of materials and the cleanliness of the surface treatment of the rotor and stator, the speed of movement of the rotor in the stator; properties of the pumped medium; security heat balance sliding surfaces within the limits allowed by the selected materials. The most often used is the simplest design and technological solution of a single-screw pump: the rotor is the screw, and the stator is the pump casing. The screw is metal, and the holder is rubber-metal with inner surface made of synthetic rubber or other elastomer.

The screw in the cage undergoes complex planetary motion. It rotates not only around its O 2 axis, its axis simultaneously moves along a circle with a diameter equal to two eccentricities (2e) in the opposite direction. This second movement of the screw is caused by its rolling on segment 2-3 and sliding on segment 5-6 of the cage walls. A fixed gear m with internal gearing and center O 1, which is the axis of the cage, has a diameter D = 4e. A wheel n with diameter d 1 = 2e rolls along it without slipping, which belongs to the screw and rotates around its axis in the opposite direction. During rotation of the screw, the center of any of its cross section continuously moves in a straight line from the top position A to the bottom position B and back. This movement from top to bottom occurs in one revolution of the screw, and a point on circle n, moving inside a stationary circle m, describes a hypocycloid. If the diameter of the moving circle is equal to half the diameter of the stationary circle, then the hypocycloid is transformed into a straight line AB of length, equal to the diameter fixed circle m.

When circle n rolls along circle m in a clockwise direction from position 1 to position 5, circle K (screw section) moves downward, and it rotates counterclockwise and slides along the wall 6-5 of the cage. Straight AB rotates at a certain angle corresponding to the shape and pitch of the helical line of the holder.

The helical surface of the screw (Fig. 16) is formed by moving the circle K along the axis screw O-O provided that the center of the circle moves along the helix M-M. distant from O-O axes by the value of the eccentricity e of the screw.

The inner surface of the cage is formed by the helical movement of the cross-sectional plane 1 - 2 - 3 - 4 - 5 - 6 (see Fig. 14), which rotates around the O 1 axis of the cage and moves proportionately along this axis.

A complete rotation of this plane by 360° with uniform movement along the axis of the holder will be the step length of the holder

where t is the propeller pitch.

Closed cavities are formed between the screw and the holder (see Fig. 15), which are filled with the pumped liquid. The cross-section of these cavities has the shape of a crescent.

Together with the rotation of the screw, cavities or chambers filled with liquid move along the axis of the cage from the receiving cavity to the discharge cavity, and for each revolution of the screw, the liquid in the chamber will move in the axial direction by the pitch length of the cage T.

The cross section filled with liquid is constant along the length of the holder and is determined by the area of ​​a rectangle with sides 4e and D or

where D is the diameter of the screw.

At a rotation speed of n revolutions, the theoretical flow of the pump is

and the actual feed

Qg = Qt ?rev = 4eDTn ?rev,

Where? r - volumetric efficiency of a single-screw pump.

The optimal law of pressure distribution along the length of the cage should be diagram 1 in the shape of a triangle OAB (Fig. 17), where AB is the length of the cage, and p is the given pressure. In practice there may be unwanted deviations. Thus, hypotenuse 2 of triangle VAB shows that operating pressure p of the pump is not distributed over the entire length of the pump OB, but only over the outer turns of the EB. This means that the tension in the working parts is high and the elastomer will be rapidly destroyed.

Hypotenuse 3 of the triangle A"OB shows that the pump is assembled with a gap and does not develop the specified pressure p, which is also unacceptable. The optimal option is when the pressure p is distributed evenly along the entire length of the holder.

Experimental curves 4, 5, 6 and 7 were taken on pumps with identical tension and different race lengths. The actual data corresponds well with theoretical diagram 1 and confirms the possibility of obtaining a proportional increase in pressure along the length of the cage. Considering that at the maximum achieved pressure of 250 kgf/cm2 the pump will not have sufficient service life, based on many years of experience, it is recommended to take into account the pressure difference between adjacent chambers: p = 45-50 m.

The length of the cage L is related to the pump pressure H, the propeller pitch and the pressure drop between adjacent chambers as follows:

L = (H / ? p + 2) t

Preload refers to the difference between the cross-sectional diameter of the screw and the inner diameter of the race. If this difference is negative, there is a gap in this working pair.

A screw pump is a unit designed for pumping solutions and liquids of high viscosity. This kind of equipment is used in many areas of industry - textile chemical and metalworking production. Screw pumps have a simple design, are reliable and have a long service life.

Screw pump design - what does the device consist of?

The main element of a screw pump is the rotor. He has cylindrical shape and a spiral groove resembling a screw or auger. The rotor is located inside a stator equipped with an elastomeric sleeve and a spiral channel. The stator itself has the shape steel pipe. The rotary spiral can be equipped with several passes. In this case, the stator spiral is always equipped with one more entry.


Along contact line Between the stator and the rotor there are areas protected from water penetration, dividing the working cavity of the pump into several parts. Due to the special arrangement of the rotor in the stator, these sections alternately open and close.

The volume of pumped liquid is adjusted by changing the number of rotor revolutions. To do this, use a frequency drive.

All pump elements are housed in a durable plastic or cast iron housing. Moreover, if a screw pump is used for a well, its body is made of stainless steel.

The operating principle of each screw unit is based on the movement of liquid along the screw axis inside the chamber. The axis is formed between the surface of the housing and the helical grooves by inserting the helical projections into adjacent grooves. Thanks to this principle of operation, a closed space, which prevents liquid from moving backwards from the device.

Nowadays, screw pumps are used in many areas of human activity. Most often this equipment is used:

• In food factories - in food production, units are used as dispensers;
• In construction - pumps are used to supply mixtures used for the production of self-leveling floors and roofing;
• At wells, devices pump out contaminated water from big amount impurities. Screw borehole pump can be used as a source with clean water, and for a well with sand;
• In the chemical industry, screw pumps pump large volumes of thick substances for further processing.

High reliability and ability to operate under high loads makes screw pumps one of the most progressive types pumping equipment.

Advantages and disadvantages of screw pumps

The high demand for screw pumps is due to their many advantages. Among them it is necessary to highlight:

• High efficiency of devices – from 50 to 70%;
• The units are capable of working with very viscous liquid, creating a pressure much higher than impeller pumps;
• Screw pumps are capable of pumping liquids with large amounts of solid impurities;
• The operating principle of the screw device eliminates the formation of pulsations, which are typical for other types of equipment;
• Screw pumps are self-priming devices, and the maximum liquid intake depth can be 8.5 m;
• The devices are compact and low level noise;
• Due to their high reliability, screw pumps rarely require repairs and do not require frequent maintenance.

Like other types of pumps, screw equipment has its own weak sides. The first disadvantage is the high cost of the units, which is why not all enterprises can afford to use them in their production. The second drawback is the inability to adjust the volume of pumped liquid.

Types of screw pumping equipment

Since screw devices are used in many applications, they differ from each other in their design features. According to their design, the units are divided into the following types:

• Screw pumps - these units are designed for pumping large volumes of aggressive chemicals and abrasives. The screw device works effectively in both vertical and horizontal positions. Often such equipment is used for water from wells and deep wells. Screw units have a simple design and relatively low cost;

• Rod pumps - these types of devices are used for highly viscous media in oil production and refining enterprises. The rod pump design includes a wellhead gland, a rotary column and a surface drive. Units of this type are characterized by high productivity and fairly high cost;

• Vacuum pumps - these units are equipped with two screw rotors rotating in opposite directions. Thanks to this design vacuum pump, the liquid first enters the area between the screw chambers and the cylinder, and then enters the exhaust port.

A screw pump for viscous liquids shows high performance, but the efficiency of the device largely depends on the correct use of it. In this regard, before purchasing a device for domestic or industrial purposes, you need to make sure that it is suitable for the chosen area of ​​application.

Which pump is better - a centrifugal pump or a screw pump?

Many people who want to buy a pump for household purposes think about what is better - a centrifugal or screw pump. Both of these types differ in their areas of use and design features.

A centrifugal pump is a fairly expensive device that does a good job of providing water. country cottage. These pumps can be used for both wells and wells. The unit device includes a fixed on the shaft Working wheel, which pushes water upward. This equipment is only suitable for pumping clean water, has high efficiency and consumes a small amount of electricity. Centrifugal pumps are characterized by high reliability and long service life.


Screw pumps are used primarily in industry. Much less often, a submersible unit of this kind is used in everyday life and on the farm. If just such a device was chosen for servicing a private home, then it should be used for pumping not too contaminated water, the amount of solid impurities in which should not exceed 150 g/m 3 of liquid.

The choice of pumping equipment mainly depends on the water it will pump. If the unit is required to supply clean drinking water, then it is better to choose centrifugal pump. If liquid is needed for irrigation, then it is better to give preference to screw equipment.

Screw and vane pumps - what are the differences?

Most inexperienced buyers often make the mistake of mistaking a vane pump for a screw pump. The differences between these types of units lie in the areas of application and characteristics of the units.

Screw devices are mostly used for industrial purposes, much less often in everyday life. Among their advantages are:

• Uniform supply volume of the pumped liquid;
• Self-priming ability;
• Excellently balanced design;
• The unit operates efficiently even if there are solid impurities in the liquid;
• High strength of parts.

The disadvantages of screw pumps include the high cost of equipment, large dimensions, increased friction of its spare parts, high level noise and ineffective cooling.

Vane pumps are used in everyday life. The centrifugal vane pump has the following advantages:

• Easy to operate and maintain;
• Possibility of connecting several vane pumps to one pipeline at once;
• Modest dimensions and weight;
• Low noise level during operation;
• Low cost of most models;
• Availability effective system cooling.

Among the disadvantages of a roller vane pump, the inability to work with contaminated water should be highlighted. The centrifugal vane pump has low efficiency, and when the flow channels are narrowed, most units overheat, which leads to their breakdown. For the production of most models, heavy steel parts are used, which, coupled with lightweight plastic body, impair the balance and stability of the instruments.

An important characteristic of a vane pump is its performance. It greatly depends on the quality of the water and the power of the unit. If the pump does not have high power, then it will not pump the amount of liquid necessary to service a private home. Therefore, for suburban housing, you should choose more powerful equipment, the purchase of which will cost much more.

Screw pumps have become widespread in the field of providing private houses and cottages with clean water from a well or well.

Every home owner knows that after purchasing real estate, it is worth thinking about providing the house with water. After all, the lack of water supply can greatly spoil the purchasing experience.

Right choice submersible pump, and in our case, a screw pump is a guarantee of uninterrupted water supply for a long time.

The screw pump for a well is well-deservedly popular among lovers of country holidays on their site, as well as among owners of cottages and houses due to its ease of operation and ease of installation. In addition, unlike a surface pump, a screw pump is versatile in supplying water from great depths.

The principle of operation of a screw pump.

The operation of screw pumps is based on the concept of an Archimedes screw.

Video about screw pump

Screw pumps are good for creating enough high pressures with a small supply of liquid. Screw pumps have become widespread recently, finding the greatest popularity in providing water from wells to private houses and cottages.

Screw pumps are most widely used in the chemical industry for pumping aggressive chemical media.