Diaphragm Performance Monitoring

A pressure gauge still requires human intervention. Someone has to turn the pump off.

A pressure switch, if wired to a NC contact will automatically shut the pump, or pumps, down.

That's my guess. I don't really have a clue.

I agree with Lyn.

Connect the pressure switch to your motor contactor and it will automatically shut down.

You can also connect a buzzer or warning lamp or even connect it to your PLC to send out an alert.

There are so many things you can do with that switch.

firstly thanks for your reply , i know the switch is for taking an action by shutting the pump down not to have further problems, however my query is when to use this kind of protection and when it's not needed knowing that both sets are having the same criticality

That is up to you, given that you are the only one to know the consequences of a failed pump.

You're looking for two documents, Mildred. One is called the Process Description. The other is called the Functional Design Specification. Find them. Read them. All will become clear.

If you find a document called a HazOp Study Report, that will be a worthwhile read too.

Bear in mind that no-one here can see either your plant or your documents.

Go automatic.

You may opt for a pressure switch but, be sure to make a redundant approach.Redundant means, make 2 independent measurements other than one for reliability's sake. When one pressure switch malfunction, the other sensor could tell the difference.

If you want some sort of diagnostics a pressure sensor with a pc monitoring or graphic logging module would be best.

Wouldn't the pressure switch keep opening and closing as the diaphragm cycles from suction to pressure and back?

You would only get half a cycle and the pump would shut off.

That's why Mildred needs the FDS, Deidre.

Not if you correctly wire it to the motor contactor! It would shut it off and you would then have to re-start the motor!