Importance of Selection of Centrifugal Pumps
IMPORTANCE OF SELECTION
The best selected pump for any duty condition may be most Hydraulically fit or with best efficiency but it may not be most suitable or cost efficient. The selection criteria must include maintainability and reliability as a foremost factors.Engineers overlook systems where the pump has to be used and lack of experience often results in under performing and oversized or wrong pumps with higher operating costs .Considering pump as a plug and play device will always add cost burden to the process.
SELECTING A PUMP
Selection can be divided into technical and commercial considerations. Various steps are taken before concluding on the pumping equipment.
STEPS
1. Complete analysis of the system
A complete system analysis is necessary before proceeding with the pump selection . An engineer should consider following points
Net Positive Suction Head (NPSHA) : Pump failures are often mistaken on number of unrelated causes and often NPSH is never examined. NPSHa or NPSH available should always be 1.5 m more than NPSHr or NPSH Required which has to be specified by Pump manufacturer. Difference less than 1.5 m will lead to Cavitation and may lead to complete failure of the pump.
Fluid Type and Specification : The Nature of fluid is very important to know before selecting a pump. Impeller Design, Metallurgy of the pumps and type of pumps are largely dependent on the specification of the fluid. Few Considerations to be taken care are Solids to be handled, Temperature of fluid, Corrosive and abrasive nature of fluid , toxicity of fluid and we should check if the fluid is highly flammable .
Criticality of the application : In case of application critical to the system a spare pump is necessary and is installed on the common header. The pump is of identical duty parameter and is used if one pump fails prematurely .
Sealing requirement : Mechanical seals are used where leakage is not permitted . The reason for Zero tolerance can be hazardous
The best selected pump for any duty condition may be most Hydraulically fit or with best efficiency but it may not be most suitable or cost efficient. The selection criteria must include maintainability and reliability as a foremost factors.Engineers overlook systems where the pump has to be used and lack of experience often results in under performing and oversized or wrong pumps with higher operating costs .Considering pump as a plug and play device will always add cost burden to the process.
SELECTING A PUMP
Selection can be divided into technical and commercial considerations. Various steps are taken before concluding on the pumping equipment.
STEPS
1. Complete analysis of the system
A complete system analysis is necessary before proceeding with the pump selection . An engineer should consider following points
Net Positive Suction Head (NPSHA) : Pump failures are often mistaken on number of unrelated causes and often NPSH is never examined. NPSHa or NPSH available should always be 1.5 m more than NPSHr or NPSH Required which has to be specified by Pump manufacturer. Difference less than 1.5 m will lead to Cavitation and may lead to complete failure of the pump.
Fluid Type and Specification : The Nature of fluid is very important to know before selecting a pump. Impeller Design, Metallurgy of the pumps and type of pumps are largely dependent on the specification of the fluid. Few Considerations to be taken care are Solids to be handled, Temperature of fluid, Corrosive and abrasive nature of fluid , toxicity of fluid and we should check if the fluid is highly flammable .
Criticality of the application : In case of application critical to the system a spare pump is necessary and is installed on the common header. The pump is of identical duty parameter and is used if one pump fails prematurely .
Sealing requirement : Mechanical seals are used where leakage is not permitted . The reason for Zero tolerance can be hazardous