A screw pump, which is also called a screw pump, is one of the varieties of rotary gear type devices. In it, the pressure head of the injected fluid is formed due to its displacement by screw rotors rotating inside the stator. There may be one or more, depending on the configuration of the device. Screw pumps are easily obtained from gears, and this is done by increasing the inclination of the teeth in them, as well as reducing the number of teeth of the gears. However, it is better to use the "original version" of the device.
The screw pump operates in accordance with the following principle. Liquid is pumped due to the fact that it moves between the helical grooves and the surfaces of the housing. The grooves are along the axis of the screw. With their protrusions, they "walk" along interchangeable grooves, which prevents the fluid from moving backward.
The screw pump is used in a fairly wide range. It can be useful for pumping gas, steam, as well as mixtures thereof or liquids with varying degrees of viscosity. They were first introduced into production back in 1936. Due to the simplicity of the design, they can work freely even in the presence of mechanical impurities having viscous fluids at a pressure level of up to 30 MPa. Such characteristics are very important for solving a wide variety of tasks. Entire installations of
screw pumps are actively used in wells designed for the extraction of methane from coal seams, as well as for pumping water from there. They are used for
oil, 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 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 a metal casing are able to withstand significantly higher loads than their counterparts placed in elastic casings. A device with a conical screw can work well in a rigid case.
The most common screw pump is a three-screw. In practice, its scope turned out to be the broadest. This is due to certain characteristic advantages of this type of equipment:
- uniform supply of a substance;
- the ability to pump liquids with solid additives, without any damage;
- an opportunity for self-absorption of liquids;
- high pressure at the outlet can be obtained without the mass of cascades of discharge characteristic of other types of pumps ;
- during operation, the device creates noise effects at a fairly low level;
- the pump mechanism is balanced very well.
This species has certain disadvantages, which are much less than the advantages:
- a sufficiently high degree of complexity in the manufacture of this type of equipment, as well as its high cost;
- lack of ability to regulate the working volume;
- idle use is simply unacceptable.