A 3" propane makeup line to refrige

[uaepiping]

A 3" propane makeup line to refrigerant surge drum has a ¾" PSV. Inlet line is also ¾". This inlet line to PSV is vibrating. It is reported that the propane makeup line is not vibrating. Now the question is as this is normally no flow line, what is causing vibration? The vibration as per Energy Institute guidelines is within Concern zone.
Can you please share your experience on the causes of PSV inlet lines vibrating without any popping up event?

 

[LittleInch]

It sounds like you've got some sort of Flow induced vibration which is creating an oscillating force close to your pipes natural frequency.

without any details of this connection it's difficult to comment further,but some sort of bracing will probably solve it.

If the inlet line is vibrating I can only assume it is quite long and flexible?

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

 

[georgeverghese]

There have been many cases of these small bore connection failures in the past resulting in fires - small bore socket welds unable to withstand constant vibration and other shearing forces were stated to be the cause of these failures. Use larger bore tee offs ( say a 3inch x 2inch branch forged tee ) and then reduce down to the required line size.

 

[uaepiping]

Thanks George and Littleinch.
George,
Though idea to change to larger size seems most pertinent, but here most "fit for purpose" solution would be to increase the rigidity of the supports as LittleInch pointed out.
For this particular line, the line branches off with a sockolet from a 3" line, goes up, makes a loop in vertical and then connected to PSV. Supports are provided at both the horizontal sections of the loop.

 

[LittleInch]

Makes a loop ??

Picture?

Drawing?

That sounds very strange for a PSV inlet line

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

 

[uaepiping]