Design of flange with O ring groove

Posted by: rajendra_g

Design of flange with O ring groove - 05/17/18 12:56 AM

I have to design a flange which has 8.5 deep o'ring groove for 10mm OD o'ring( <75A Shore Durometer) m = 0.5 & y = 0.

I designed this flange in PV Elite, Since y=0 , PV Elite do not give calculation for mimimum gasket width and client is asking to ensure that that the joint is leak proof.

Is there any reference to design this type of flanges.
Posted by: Ray_Delaforce

Re: Design of flange with O ring groove - 05/17/18 08:58 AM

Hello Rajendra_g,

This is a very specific question. It would be better to raise the issue through customer support. Could you kindly raise an SR for this issue, and I shall look at you PV Elite file.
Posted by: mariog

Re: Design of flange with O ring groove - 05/17/18 11:19 PM

As preliminary remark, in case you have self-energized gaskets as O-rings are classified, m=0 and y=0. It seems you have considered values for plain gasket elastomers.

For O-rings is valid the following paragraph of ASME VIII Div 1
"Self-energizing gaskets may be considered to require an inconsequential amount of bolting force to produce a seal. Bolting, however, must be pretightened to provide a bolt load sufficient to withstand the hydrostatic end force H."

The problem gets more complicated (and not addressed by Div1) when you have not only P load (H= total hydrostatic end force= 0.785PG^2) but also a bending moment and a tensile axial force, case when the bolting must be sufficient to withstand all loads (P, FA and M). In this case you would change Div1 requirement as the bolt load must be sufficient to withstand a force H+FA+4M/C (but this is only my opinion).
[Div 2 seems to suggest for other types of gaskets H+FA+4M/G, but this is a scenario when M effects are on G rather than C, which is hard to believe for O-rings].

Just hope you shall post here a summary of Customer Support resolution about how they suggest to solve it.