Critical systems should always be equipped with more than one pump. Choosing between the installation of one or more backup pumps depends on the costs of the installation and
- how critical the operation of the system is - a water supply system for a hospital is more critical than a chilled water cooling systems for a home
- the delivery and installation time of a new pump
If two or more pumps are used, the operation between the pump should be systematically alternated to achieve equal wear.
Alternatives for Alternating Pumps
Pumps can be systematically alternated by
- manual alternation - where the operator selects the lead pump and the sequence of the lag pumps
- duty alternation - where the lead pump change every time the pump or system is stopped
- timed alternation - where the lead pump is switched by a timer or clock
- equal run time - where the lead pump is switched to achieve the same operating time for each pump
Note! Running an automatic system for equalizing the wear of the pumps
- has the advantage of extending the time before repair and reinvestments
- has the disadvantage that all pumps may wear out on at the same time - reducing the operation safety for the whole system
Piping systems and pumps - centrifugal pumps, displacement pumps - cavitation, viscosity, head and pressure, power consumption and more.
An introduction to Centrifugal Pumps.
The characteristics of stable and unstable flow.
Introduction tutorial to positive displacement pumps basic operating principles.
Centrifugal pumps vs. positive displacement pumps.
Adding head and flowrate for pumps arranged in parallel vs. serial.
Mean Time Between Failure - MTB and reliability of machine components and systems.