I. Principles for selection of centrifugal pumps
1. Choose pumps for different purposes and types according to the nature of the fluid being transported.
2. The flow and head must meet the maximum load required in the work.
3. When choosing a pump from the point of view of energy saving, on the one hand, it is necessary to choose a pump with high efficiency;
4. In order to prevent cavitation, the required cavitation amount NPSHa of the pump is required to be less than the cavitation allowance NPSHa of the device.
5. Select the pump according to the special requirements of the conveying medium.
6. The selected pump should have the characteristics of simple structure, easy operation and maintenance, small size, light weight, and low equipment investment.
7. When there are two or more specifications of the pump that meet the user’s requirements, the one with the comprehensive elevation should be the final selected pump model.
2. Determination of the flow and head of centrifugal pump selection
1. If the centrifugal pump has given the minimum, normal and maximum flow in the production process, The maximum flow should be considered.
2. If only normal flow is given in the production process, a certain margin should be considered. For large flow and low lift pumps with ns>100, the flow margin is 5%. For ns
