The plunger metering pump mainly has two kinds of valve pump and valve free pump. The plunger metering pump is widely used in the field of petrochemical industry because of its advantages of simple structure and high temperature and high pressure. Because of the shortage of ordinary piston pump under high pressure, the valve less rotary piston metering pump has received more and more attention. It is widely used in the measurement and addition of high viscosity media such as syrup, chocolate, cement grinding aids and petroleum additives. Because of the structural drawback that the metering medium and the lubricant inside the pump can not be completely isolated, the plunger metering pump is limited in the application of high pollution prevention and fluid metering applications.

Advantage：

1. lower prices

2. can transport high viscosity medium, not suitable for transporting corrosive slurry and dangerous chemicals.

When the 

3. flow is up to 76 m 3/, the flow rate is within the range of ten percent to one hundred percent, the measurement accuracy is up to one percent and the maximum pressure can reach 350 MPa. When the pressure of the exit is changed, the flow rate is almost constant.

Shortcomings:

1. unsafe discharge device.

2. shaft seal is sealed for packing. It has leakage and needs to adjust the packing periodically. Packing and plunger are easy to wear, and the packing ring should be flushed and discharged by pressure.