Choose Pump

Item No. 1:  Principle

1.   Pump chosen should meet with technical requirements such as capacity, head, pressure, temperature, NPSH(r), suction height etc.

2.   Medium of liquids character and requirements

A:  For medium which is flammable, explosive, toxic and valuable, pump shaft should be reliable or no leakage such as magnetic drive pump, diaphragm pump, screened pump etc.

B:  For corrosive medium, pump parts which contact with liquids should be anticorrosion such as AFB corrosion resistance pump made from stainless steel, CQF engineering plastic magnetic pump etc.

C:  For liquids with solid grain, pump parts which contact with liquids should be abrasion proof and shaft seal is washed by cleaning material.

3.   Mechanism: Reliable operation, Low noise, Small vibration.

4.   Economic cost: equipment cost, cost of operation, maintenance, cost management etc are the lowest.

5.   Centrifugal pump has the advantages of high rev, small volume, light weight, high efficiency, big capacity, simple structure, liquid transport without pulsation, stable performance, easy to operate and maintain etc

Centrifugal pump can be chosen as far as possible except below conditions:

A:  When there is metering requirement, metering pump should be chosen.

B:  When high head and small capacity are needed or no suitable centrifugal pump with high head at small capacity can be chosen, reciprocating pump can be chosen. If low NPSH is only needed, vortex pump can be chosen.

C:  When big capacity at low head is needed, axial pump and interflow pump can be chosen.

D:  When medium viscosity is high (650-1000mm2/S), rotor pump and reciprocating pump (gear pump, screw pump etc) can be chosen.

E:   When air content of medium is 75% and capacity is small and viscosity is smaller than 37.4mm2/S, vortex pump can be chosen.

In the occasions of frequent startup and inconvenient irrigation pump, self priming pumps such as self priming centrifugal pump, self –priming vortex pump and air(electric) diaphragm pump can be chosen.

Item No.: 2: Rule

Process flow, water feed and discharge requirements such as capacity, head,liquids, pipeline and operation conditions etc

A. Capacity(flow rate) is one important data of technical performancefor pump. It relates the discharge and transfer ability.For example: designing institute can calculate out normal and maximum and minimum capacity. When choose pump, maximum capacity is as the rule and normal capacity is taken account of. If maximum capacity is not known, 110% normal capacity can be looked on as maximum capacity.