ASME Flange Analysis with oring seal 1

[noreaster]

I have a hydraulic cylinder application where my customer wants the cylinder stamped ASME Sect VIII.

Problem is that the head and the barrel flange are sealed by an oring groove on the bore and not on the face as given in all of the sample flanges. There is an o-ring face seal on the flange, but it is used for water exclusion.

The problem is that the AI and reviewing Engineer want to use this as the diameter for pressure loading, which increases the bolting force. It is not meant to seal 3000 psi. The sealing area is on the id bore.

Having trouble convincing them that
1) this oring seal has integrity (I have specs to show the oring gland design)
2) if I use the od of the oring gland, it will develop the same moment and from that I can calculate the flange thisckness.

Andrew Hall
PEI, Canada

 

[btrueblood]

Hmm...if the bore seal fails, will not the outer seal then take the pressure load? If there was a blow-out disk, or some other feature to relieve pressure if the inner seal fails, then the o.d. seal carrying full rating pressure could be argued to not be a design condition...