Flow switch for pump protection

[flinana]

Hi,
For pumps pumping from a tank, our engineering has decided to use a flow switch for pump protection. I was wondering if the pump should also stop for low level in the tank, or if the flowswitch is enough.

thanks,

 

[JLSeagull]

What type of pump?

From a tank, a flow transmitter with low flow interlock could provide pump protection. It would require a startup time delay. A low flow recirculation could help too. Mechanical flow switches are hopeless. Use the low level interlock from the level transmitter regardless of the flow interlock.

 

[BigInch]

Go to the control variable's source. Use the instruments that directly measure your control variable. If you want to stop on low flow, a flow switch may be best. If you want to stop when the tank gets low (or high) go with tank level switches. If you want to do all three, go with all three.

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[Joesteam]

Another option is to use a low pressure switch on the inlet of the pump as a pump shut-off. This depends also on the normal inlet head....

 

[Ashereng]

Flow switch for pump protection is very common. This protects the pump.

A low level switch in the tank would prevent pumping below a level, perhaps preventing "uglies" from being pumped out.

They serve slightly different purposes.

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