Centrifugal Pumps

Cavitation in centrifugal pumps

Centrifugal pump is designed as a hydraulic machine to move liquids. Cavitation or entrained gas causes problems in pump performance. Pump cavitation is caused by vaporization of the liquid in pump suction due to several reasons. Pump cavitation can damage the pump impeller blades and frequent dry running of pumps can damage other pump parts.

This post covers definition, description and causes of pump cavitation along with the consequences and damages resulting from pump cavitation.

Centrifugal pump priming

Priming of a centrifugal pump is done by filling the pump with a liquid service that replaces air or other gases/vapor. This is done mainly to avoid the dry running of a centrifugal pump. This post explains the details of centrifugal pump priming.

Pump operations

Pump operations refer to the procedures and activities involved in operating a pump, which is a device used to transfer fluids or gases from one location to another. Pump operations can include the start-up procedure, monitoring, maintenance, shutdown procedures and troubleshooting. Effective pump operations require careful attention to all these points.

Centrifugal pump maintenance

Proper maintenance of centrifugal pumps is critical to keep them operating efficiently and reliably, prevent breakdowns, and extend their lifespan. Check types of pump maintenance along with troubleshooting and inspection / maintenance guidelines.

Theory and Equations for the centrifugal pumps

Theory of centrifugal pumps and key equations typically used for designing of such pump systems are discussed in this post.

Net Positive Suction Head
Pump Performance curves
Pump Specific Speed and Pump Suction Specific Speed
Pump power
Pump affinity laws

Internal recirculation in centrifugal pumps

A pump operating at lower capacity than design limits can suffer from recirculation which occurs internally in the pumps. When the capacity of a pump is reduced by throttling (or as a result of an increase in system head), a secondary flow called recirculation begins. All impellers have a critical capacity at which recirculation occurs.

Typical P&ID arrangement for centrifugal pump

A typical Piping and Instrumentation Diagram (P&ID) of a centrifugal pump system, presents basic concepts in designing and operating a pumping system.

Typical centrifugal pump datasheet

When issuing a Request for Quotation (RFQ) for centrifugal pumps, it is strongly advisable that a detailed pump datasheet is included. A datasheet including as much information as possible will save the pump manufacturer-supplier considerable time from having to browse through tens or even hundreds of pages of specifications in order to find the necessary information in order to provide the best quotation in a timely manner.

Centrifugal fire fighting pumps

In accordance with NFPA 20 (2007 edition), fire fighting pumps shall be specifically dedicated and listed for fire protection service. Usually, centrifugal pumps are used in fire fighting. This post contains guidelines for selecting the proper type of fire fighting pumps and deciding capacity, installation location etc. for these pumps.

Centrifugal pump start up procedure

Pump start-up procedures are the steps that must be followed to properly start and operate a pump. Starting a pump involves a series of steps to ensure that the pump is functioning correctly and efficiently, and that it is not at risk of damage or failure. 

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