High pressure limitation for equipment

[Liad]

Hello,

We plan to have a positive displacement pump that can get up to a discharge pressure of 30 bar.
we will have a pressure relief valve after the pump that will work at around 10 bar, and a pressure transmitter after the pump so we can stop the pump if we reach 8 bar.
I know that a pressure relief valve can fail or clog, and the control will only work after a few seconds.
In this case, from an engineering point of view, should I choose the pipes and other equipment that will be resistant to the maximum pressure of the pump? or I can choose them to be resistant to around the pressure of the relief valve?

Thanks
Liad

 

[LittleInch]

Pressure relief valves rarely fail unless you think there is a good reason why they should clog up. If in doubt add a second one.

Also how long has this got to respond? Can you add an accumulator or something to give the control system time to work?

The low risk option is to eliminate the hazard, i.e. chose pipes etc which cannot burst.
or add another valve or a bursting disc

But where does 30 bar come from? PD pumps can achieve very high pressures when locked in unless the driving force is limited e.g. AODD pumps

Your design pressure would need to be 10 bar anyway.

What size and fluid are we talking about here? Design code being used?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Liad]

Yes, we thought about installing another pressure relief valve. the fluid is phenolic resin so ש blockage in the pressure relief valve is possible in a certain situations.
The gear pump discharge maximum pressure is around 30 bar.
The control will stop the pump after 2-3 seconds of very high pressure.
I'm not sure what you mean in: What size and fluid are we talking about here? Design code being used?

So you think taking a 10 bar as a design pressure and maybe adding another PRV is acceptable?
Thanks

 

[LittleInch]

When you say the MOP of the pump is 30 bar is this the m head or pressure when flowing and hence limited by the motor power?

Gear pumps will continue to pump and increase pressure until either the motor stalls, the gears break or a pipe fails. Are you sure this pump doesn't have its own internal PRV?

Anyway from your other posts it looks like we are at a small pipe size? Pressure rating has little to do with the cost unless there is some other but of kit.

You should arrange your system to not exceed your psv set pressure to prevent clogging of the valve. I don't understand why you think there should be a delay of a few seconds for the set point control.

Does the flow stop instantaneously?

Is there a design code for the piping??

Normally you need to use something to stay inside national regulations.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Snickster]

In cases where there is chance of relief valve clogging due to service fluid, a rupture disc is installed on the inlet of the relief valve.

 

[Liad]

Thank you all guys. The pump has an internal PRV and I will add another rupture disc just in case.