1、 Determine the pressure: the rated pressure of the selected metering pump is slightly higher than the actual maximum pressure required, generally 10~20% higher. Don't choose too high. Too high pressure will waste energy and increase equipment investment and operating costs.

2、 Determine the flow: the flow of the selected metering pump shall be equal to or slightly greater than the flow required by the process. It is better to use the flow of metering pump within 30~100% of the rated flow range of metering pump, at this time, the repeatability of metering pump is high. Considering the economy and practicality, it is recommended that the actual required flow of the metering pump be 70~90% of the rated flow of the metering pump.

3、 Determining the material of pump head (hydraulic end): after the specific model and specification of metering pump are determined, the material of overflow part is selected according to the properties of overflow medium. This step is very important. If it is not selected properly, it will cause medium corrosion, damage to overflow parts or medium leakage, pollution of the system, etc. Serious accidents may also occur.

4、 Other aspects: when selecting the metering pump, it is also necessary to consider the accuracy level of the metering pump required. The higher the accuracy level, the greater the input. Generally, the working temperature of metering pump is - 30~100 ℃, and the working temperature range of special metering pump is wider (for example, the delivery temperature of high-temperature liquid metering pump with insulation jacket can reach 500 ℃). The particle size of the medium shall be less than 0.1mm. For the medium larger than 0.1mm, the flow passage structure of the pump can be changed to meet the needs. For the viscosity of the medium (official account account: pump manager), it should generally be 0~1000mm/s, and the special metering pump can reach 6000 mm2/s. The flow of the mechanical diaphragm metering pump is the maximum flow measured under the calibrated rated pressure (when delivering clean water at room temperature). If the pressure drops, the output flow will be higher than the calibrated flow.