1. Determine the material of the pump head (hydraulic end) of the metered dose pump:
After the specific model and specifications of the metering pump are determined, the material of the flow part is selected according to the properties of the flow medium. This step is very important. If the selection is improper, it will cause media corrosion to damage the flow-through components or media leakage to pollute the system. In severe cases, a major accident may occur.
2. Determine the metering accuracy level of the metered dose pump:
When selecting a metering pump, it is also necessary to consider the accuracy level of the metering pump required. The higher the accuracy level, the greater the investment.
The general operating temperature of metering pumps is -30~100℃, especially the operating temperature of metered dose pumps is wider (such as high-temperature liquid metered dose pumps with thermal insulation jackets, the transportation temperature can reach 500℃).
Regarding the particle size of the medium, the requirement should be less than 0.1mm. Regarding the medium larger than 0.1mm, the flow structure of the pump can be modified to meet the demand.
Regarding the viscosity of the medium, it should generally be between 0 and 400 cP. The metered dose pump equipped with a high-viscosity check valve can reach 4000cP. The flow rate of a mechanical diaphragm metered dose pump is the maximum flow rate measured under the calibrated additional pressure (when clean water is transported at room temperature). If the pressure drops, the output flow rate will be higher than the calibrated value.
3. Determine the pressure of the metered dose pump:
The additional pressure of the selected metered dose pump is slightly higher than the actual maximum pressure required, generally 10-20% higher. Do not choose a metered dose pump with too high pump pressure. Too high pressure will increase the power, thereby increasing equipment investment and operating costs.
4. Determine the flow rate of the metered dose pump:
The flow rate of the selected metered dose pump should be equal to or slightly greater than the flow rate required by the process. The use scale of the metering pump flow rate is preferably 30-100% of the additional flow rate of the metered dose pump. At this moment, the repeated reproduction accuracy of the metered dose pump is high. Considering the economy and practicality, it is recommended that the actual demand flow of the metered dose pump should be selected as 70-90% of the additional flow of the metered dose pump.