Rupture disc reaction force

[heymans]

Dear,

I am calculating some lines for stress that contain rupture disc.
I did a little bit thinking about the reactions that occur when the disc breaks ... but now I am a little bit confused.
Which phenomenoms occur hen the disc breaks? shockwave ... in wich direction ... goes it up or downstream ...? in wich direction is the reaction force?

My idea was that when the disc breaks, a shockwave is created. The wave travels upstream and creates a force (reaction force) in every obstacle (elbows, ...).
A second reaction occurs when the high pressure gases are relievede in the atmosphere. Here another upstreamforce is creae in the first upstream elbow.

kind regards,

Pieter Heymans

 

[Zapster]

Reaction forces are similar for PSVs and Rupture Disks. See

http://www.eng-tips.com/viewthread.cfm?qid=156173&page=1

for some interesting discussion.

 

[JimCasey]

Don't have elbows downstream of the rupture disc. Keep the piping short and direct.

THe reaction force pushes against the flow direction. Think of it as a rocket nozzle. If you have 150 psi burst, on a 4" line (approx 12.5 square inches, a pretty good estimate of the initial force is 12.5 x 150, or a little over 1800 pounds of force.