It is generally referred to as a screw pump, which is used for pumping liquids, conveying liquids and adding pressure to liquids. From the point of view of energy, a screw pump is a machine that converts energy, which converts the mechanical energy of the prime mover into the energy of the liquid being transported, increasing the flow rate and pressure of the liquid.
The function of the screw pump is generally used to draw the liquid from the lower part of the land, along the line to the higher ground. For example, in our daily life, we use a screw pump to pump water from the river and the water in the pond to irrigate the fields. The water in the deep well is pumped up and sent to the water tower. Because of liquid after screw pump pressure can improve the effect of screw pump can also be used for the liquid suction from the low pressure vessel, and to overcome resistance to high pressure along the container or other where it is needed, for example, boiler feed screw pump suction from the low pressure water tank to the high pressure in the boiler steam drum water supply. The performance range of screw pump is very wide, and the flow of giant screw pump can reach hundreds of thousands of m3/h. The miniature screw pump flow is below a few dozen ml/h. The pressure can be as high as l000mpa. Minimum conveying liquid temperature to - 200 ℃, the highest can reach more than 800 ℃.
There are many kinds of liquid in the screw pump, which can carry water (water, sewage, etc.), oil, acid lye, emulsion, suspension and liquid metal. Since most of the screw pumps that people see are used to carry water, they are conventionally called water screw pumps. However, the term, as the general term for a screw pump, is obviously not comprehensive.