Safety valves Vs Water hammer.

[Hari Mech]

Hi Obturator and others,

I need to know why valve sizing is been done without considering water hammer scenario?

If there is a safety valve in the discharge line with a shutoff valve at the end, when I close the shutoff valve suddenly, which leads all the inertia of the flowing liquid to act on the piping also the devices connected to it. Since the safety valve is in the line, Consider a conventional type JOS-E, will the water hammer act on the disc and make it open for a short period of time?....Please share your experience on this, because I have never seen a datasheet with anything mentioning about water hammer in safety valves.

 

[LittleInch]

In short yes it can. Short duration "lifting" of valves occurs if the design doesn't purposely allow for pressure surge on valve closure.

However this is part of the design of the system to avoid this.

Sometimes a spring type valve is used as a pressure relief to limit pressure surge.

The valve set point comes from design. The valve supplier knows nothing about the system his valve is going to fitted into so there is no point noting it on a data sheet.

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

 

[RVAmeche]

This particular case should also be resolved thru better operations/control. If the shutoff valve operation is causing water hammer, the actuation speed needs to be reduced to limit this effect.