The piston, plunger, or diaphragm in the pump cylinder reciprocates to increase and decrease the working volume of the cylinder to transport the liquid or to pressurize the positive displacement pump. The reciprocating pump is divided into three types: piston pump, plunger pump and diaphragm pump.
The main features of reciprocating pump are: high efficiency and wide efficiency.
It can achieve very high pressure, and the pressure change can hardly affect the flow rate, so it can provide constant flow.
It has the ability of self-priming, conveying liquid and gas mixture, specially designed for conveying mud, concrete and so on. There is a large pulsation of the flow and pressure, especially the single-acting pump, because of the acceleration of the piston motion and the discontinuity of the fluid, the pulsation is greater. It is usually necessary to set the air chamber on the discharge line (sometimes on the tube) to make the flow more uniform. Double acting pump and multi - cylinder pump can also improve the non - uniformity of flow.
Low speed, large size, complicated structure, special pump valve, high cost of manufacturing and installation. The piston pump is mainly used for water supply, and the manual piston pump is a kind of domestic water pump. The plunger pump is used to provide the high pressure liquid source, such as the high-pressure water supply of the hydraulic press, and the piston pump can be used as drilling mud pump and pump in the oil field. The diaphragm pump is particularly suitable for conveying highly toxic, radioactive, corrosive liquids, valuable liquids, and liquids containing abrasive solids. The diaphragm pump and plunger pump can also be used as a metering pump.