I have to mate two sections of something that could be reasonably approximated by a tube, though the material is stainless steel, and the cross-section is very non-circular, so I cannot use an o-ring. The walls are thin and the exterior must remain flush, so a flange/gasket is also out.

Are there established methods for pressure sealed mating of non-circular cross-sections?

Worth mentioning I will be able to compress the two pieces via internal screws.

The diagram below shows some examples of what I might expect appropriate solutions may look like:

Diagrams of possible mating geometries

The left most is how the parts are now, with a flat mating surface. This would provide a terrible seal. The right two are possible solutions, but I would really like some precedence to justify my design.

Any guidance or references would be greatly appreciated.

EDIT: To address the comments, the wall thickness is 1/32". I will post a picture of the cross section below. Only the channels are pressurized against near vacuum in the internal volume and in the exterior. The gauge would be at max ~10 bar. There is no limitation on roughness of the channels. I cannot weld them because being able to open and close the part is a critical design feature. Gaseous Nitrogen is the fluid.

Sealing between the channels is not necessary.

Cross-section of part

  • 3
    $\begingroup$ o-rings can adapt to non circular shapes, as long as you give the groove shape several o-ring-width's of radius. rectangular o-ring-like gaskets exist too. face seals can be any shape if you have axial force and something to contain the seal in place laterally... can you show thickness, pressure/ vacuum range, and more part detail regarding how it's non circular? $\endgroup$
    – Pete W
    Oct 26, 2021 at 22:18
  • $\begingroup$ a sleeve around it or a non-standard 3-D gasket $\endgroup$
    – Tiger Guy
    Oct 26, 2021 at 23:18
  • $\begingroup$ Copper gasket___ $\endgroup$
    – RC_23
    Oct 27, 2021 at 1:25
  • 2
    $\begingroup$ So weld it. Stainless can be welded. $\endgroup$
    – Solar Mike
    Oct 27, 2021 at 5:01
  • $\begingroup$ Adding to PeteW's comment: first, you seem to claim there's not enough thickness for a gland, so why do you think a shaped O-ring (easily obtained from major manufacturers could be used? $\endgroup$ Oct 28, 2021 at 13:32


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