Safety Relief Valve Connectors w/ flexible joint
Safety Relief Valve Connectors w/ flexible joint
(OP)
I've just run across some of these in a power plant - but have never specified or installed one. I think I understand what they are used for - the flex connector isolates the relief valve discharge piping from the valve itself both from thermal movement and movement due to force.
Is there a general guideline that should be used in applying these items? My personal feeling is that the relief piping on at valve set at 15# with a low flow wouldn't need one, but there must be some number where it makes engineering sense to use them.
Is there a general guideline that should be used in applying these items? My personal feeling is that the relief piping on at valve set at 15# with a low flow wouldn't need one, but there must be some number where it makes engineering sense to use them.





RE: Safety Relief Valve Connectors w/ flexible joint
What kind of flexible joint? An expansion joint or flexhose?
Intalling a weak link like this in a relief sysytem doesn't sound like a good idea to me. The higher the pressure, the more I would advise against it.
If you do do something like this, you piping on both sides of the flexible connection must be very well restrained.
My 2 cents,
NozzleTwister
Houston, Texas
RE: Safety Relief Valve Connectors w/ flexible joint
http://railmex.com/proinf/bej/svc/svc-w.html
OR
http://www.hyspan.com/relifeConnectors.html
I've never seen them before - installed or sold to me.
RE: Safety Relief Valve Connectors w/ flexible joint
Thanks for you quick reply.
I've never seen these either. As a pipe stress engineer, I know I would have a hard time getting the project to accept using something like this except as the last resort in a low pressure application. Additional drain piping/tubing would also be requird to drain pocketed liquid.
NozzleTwister
Houston, Texas
RE: Safety Relief Valve Connectors w/ flexible joint
http://www
I suppose the bellows provides an additional measure of containment to address the potential for blowback where the smaller pipe is inserted inside the larger.
RE: Safety Relief Valve Connectors w/ flexible joint
With the bellows connector shown, it appears that blowback would be avoided. The stack would need to be supported much like a drip pan stack, but free to follow the valve outlet as the header jumps around. Also, if would be highly prudent to provide a positive drain so the outlet of the valve could not fill with condensate/rainwater.
RE: Safety Relief Valve Connectors w/ flexible joint
Edward L. Klein
Pipe Stress Engineer
Houston, Texas
"All the world is a Spring"
All opinions expressed here are my own and not my company's.
RE: Safety Relief Valve Connectors w/ flexible joint
I look and look at these and can't figure out what exact problem they solve. I'll have a flash of an idea, but when I put the logic to it - it doesn't pan out.
What I've found is that the plant engineers where these are installed - think they are required on all PRV's - because they are installed on their existing PRV's. I'm trying to work through with them why they are not needed - and that we just need to support the line properly.