Pump selection principles
1. Make the type and performance of the selected pump meet the requirements of process parameters such as device flow, head, pressure, temperature, cavitation flow, suction head, etc.
2. The requirements of the medium characteristics must be met.
For pumps that transport flammable, explosive, toxic or precious media, the shaft seal is required to be reliable or a leak-free pump is used, such as a magnetic drive pump, diaphragm pump, and shielded pump; for pumps that transport corrosive media, the convection parts are required to be made of corrosion-resistant materials, such as AFB stainless steel corrosion-resistant pumps and CQF engineering plastic magnetic drive pumps.
For pumps that transport media containing solid particles, the convection parts are required to be made of wear-resistant materials, and the shaft seal is flushed with clean liquid when necessary.
3. High mechanical reliability, low noise, and low vibration.
4. Economically, the total cost of equipment, operation, maintenance and management fees should be considered comprehensively to minimize the total cost.
5. Centrifugal pumps have the characteristics of high speed, small size, light weight, high efficiency, large flow, simple structure, no pulsation during infusion, stable performance, easy operation and convenient maintenance.
Therefore, except for the following situations, centrifugal pumps should be used as much as possible:
When there is a metering requirement, a metering pump should be used.
When the head requirement is very high, the flow rate is very small and there is no suitable small flow and high head centrifugal pump available, a reciprocating pump can be used. If the cavitation requirement is not high, a vortex pump can also be used. When the head is very low and the flow rate is very large, an axial flow pump and a mixed flow pump can be used.
When the medium viscosity is relatively large (greater than 650~1000mm2/s), a rotor pump or a reciprocating pump (gear pump, screw pump) can be considered.
When the gas content of the medium is 75%, the flow rate is small and the viscosity is less than 37.4mm2/s, a vortex pump can be used.
For occasions where starting is frequent or filling the pump is inconvenient, a pump with self-priming performance should be selected, such as a self-priming centrifugal pump, a self-priming vortex pump, and a pneumatic (electric) diaphragm pump.