Pumps Protection

I would like to know if it is better to use a high or low pressure switch upstream and downstream a pump in a certain pumping station for pump protection.

Depends on what the system is.

It all depends on what you are tring to protect from.

Dead heading you would check high pressure after the pump.

Cavitating you would want to check flow not pressure.

Ok to start maybe head pressure before.

Depends on process

Good luck
Cowboy

Running dry can be destructive to fluid pumps. We have done pumps on fluid containers which were sitting on load cells (the containers, not the pumps). Used the weight reading to stop the pumps before the reservoir would run completely empty. I am not saying such would always be the best way to go about. It did nicely for pumping some fairly aggressive fluids (hard to find suitable sensors, customer wants to limit additional connections to the bare minimum in order to minimize chance of leaks, etc).

Hi,

What are you trying to protect? Dry run? Over pressure on another device? Not stopping?

That is the main factor to consider.

just the cowboy said:

It all depends on what you are tring to protect from.

Dead heading you would check high pressure after the pump.

Cavitating you would want to check flow not pressure.

Ok to start maybe head pressure before.

Depends on process

Good luck
Cowboy

Click to expand...

Will a low discharge pressure switch protect the pump from cavitation ?

I don't like them

DF1 said:

Will a low discharge pressure switch protect the pump from cavitation ?

Click to expand...

If you get a clogged input, ea.. frozen line a low pressure sw will still read a good head pressure.

Depending on how close it is mounted you could get a low pressure because flow is so good.

DF1 said:

Will a low discharge pressure switch protect the pump from cavitation ?

Click to expand...

Always measure what you want to know as directly as possible. If you are worried about cavitation measure suction pressure.

If cavitation is the main concern and appears to be happening or potentially happening, then measuring suction pressure and comparing against the NPSH curve of the pump (specs) and also measuring discharge flow simultaneously to ensure the pump is not running off the end of it's curve.

Pumps can cavitate from multiple things, mainly incorrect NPSH (suction pressure) OR by too much flow at the discharge end.

If you are not sure, send me the pump curve or pump model number and I can help.

You would need a 4/20ma flow meter on the discharge and 4/20ma vacuum pressure transducer on the intake