Crush Ring Metal Seal Design

[CanadaTech]

I am looking for theory in regards to the design of and application of crush ring metal seals.

I have been scaling up the designs of other manufactures but have only been having success at pressures lower than 15 000 psi. At higher pressures, success is moderate.

 

[EdDanzer]

The difficulty with metal seals is the lack of elasticity. One a metal ring is deformed to seal imperfection in the mating surfaces it only takes a few microns of deflection to allow a leak.
We build hydraulic cylinder that see pressure spikes over 15,000 psi. When doing FEA on the parts there is quit a bit of deflection in these parts.

http://www.danzcoinc.com/StepLock_seal_white_paper_01_28_03.pdf

Is a link to show the barrel swell on a 4” bore cylinder.
We have also built a 20” diameter pressure vessel and use a soft aluminum sheet metal seal. When pressure testing, the deflection in the cover would make the seal leak.