A pump is a machine that conveys or pressurizes a fluid. It transfers the mechanical energy of the prime mover or other external energy to the liquid, making the liquid energy increase. The pump is mainly used to transport liquids such as water, oil, acid-base liquid, emulsion, suspension emulsion and liquid metal, and can also transport liquid, gas mixture and liquid containing suspended solids. Pumps can usually be divided into three categories: positive displacement pumps, dynamic pumps and other types of pumps according to their working principles. In addition to classification by working principle, it can also be classified and named by other methods. For example, according to the driving method, it can be divided into electric pump and turbine pump; according to the structure, it can be divided into single-stage pump and multi-stage pump; according to the purpose, it can be divided into boiler feed pump and metering pump; Water pump, oil pump and mud pump, etc. According to the structure with or without shaft, it can be divided into linear pump and traditional pump. The water pump can only transport the flow with the fluid as the medium, and cannot transport the solid.