Inhalation and discharge of working medium of piston metering pump directly pass through reciprocating motion of plunger, medium contacted with plunger and seal, selection of suitable material and sealing form of plunger can ensure ideal performance of pump in operation. plunger metering pump includes two kinds of valve pump and valveless pump. plunger metering pump is used in petrochemical industry because of its simple structure, high temperature and high pressure. The plunger is made of stainless steel and oxide ceramics. Oxidized ceramics have the characteristics of corrosion resistance, high hardness and good wear resistance.

Valveless rotary piston metering pump is paid more and more attention to the shortcomings of ordinary piston pump under high pressure of high viscosity medium. It has been widely used in high viscosity media, such as syrup addition measurement, chocolate and petroleum additives. Because of the shortcomings of the structure, there is no fully isolated pump between metering medium and lubricating oil. Plunger metering pump is limited by many applications in high pollution prevention and fluid metering. Plunger metering pump is used to accurately convey solid particles in pressure-free liquid or pressure vessels and pipelines. Different types of plunger metering pumps can be equipped with variable frequency motor (receiving 4-20mA current signal) or explosion-proof motor according to requirements. The plunger pump head has simple structure, EC knowledge economy and high precision. It needs to be well selected and maintained, and the horizontal automatic matching between plunger and seal ensures that the wear between them is small.