A pump is a machine that transports or pressurizes a fluid. It transfers the mechanical energy of the prime mover or other external energy to the fluid, increasing the fluid's energy. Pump is mainly used to transport liquids such as water, oil, acid and alkali, emulsions, suspoemulsion and liquid metal, but also liquid and gas mixtures and liquids containing suspended solids. Pump can usually be divided into working principle of positive displacement pumps, power pumps and other types of pumps three categories. In addition to the principle of classification, but also by other methods of classification and naming. For example, according to the driving method can be divided into electric pump and hydraulic pump; According to the structure can be divided into single-stage pump and multi-stage pump; According to the use can be divided into boiler feed pump and metering pump; According to the nature of liquid can be divided into Pumps, pumps and mud pumps. According to whether the shaft structure, can be divided straight line pump, and the traditional pump. The pump can only deliver the fluid as a medium of the logistics, can not transport solids.