A pump is a machine that delivers or pressurizes a fluid. It transfers the mechanical energy of the prime mover or other external energy to the liquid, increasing the energy of the liquid. The pump is mainly used to transport liquids such as water, oil, acid and alkali, emulsion, suspoemulsion and liquid metal, as well as liquids, gas mixtures and liquids containing suspended solids. Pumps can usually be divided into three types according to the working principle: positive displacement pumps, power pumps and other types of pumps. In addition to classification by working principle, they can be classified and named by other methods. For example, according to the driving method, it can be divided into electric pump and water pump, etc.; according to the structure, it can be divided into single-stage pump and multi-stage pump; according to the application, it can be divided into boiler feed water pump and metering pump; Pumps, oil pumps and mud pumps. According to the shaft structure, it can be divided into linear pumps and traditional pumps. The pump can only transport fluid-based streams and cannot transport solids.