High pressure window sealing

[magnusrm]

Hi.
Im looking at a deep sea underwater camera housing, with a conical acrylic window.
At first I thought I would go for place the O-ring grooves on the conical part of the contact face(A), as this would lead to a tight fit, and minimum extrusion risk.

I was worried about the contact pressure between the metal and acrylic, as I would expect a bit of plastic to creep inside the groove and hinder the window from moving "freely".
I therefor went for a standard radial design (B).

However, doing a simple analysis shows that the window will contract about over a millimeter in radial direction (80 MPa pressure)

Do you have any input or experience with a conical o-ring mount? Any other input?

Thanks alot!

 

[Chpal1984]

I would just say the obvious, make sure you check the differential thermal expansion.

 

[iainuts]

The force on the window due to pressure is the differential pressure times the area. You can't change the pressure differential but you can change the area. Is there any need to seal on the OD (or toward the OD) of the window? Why not put the seal on the conical surface like you wanted to initially, but put it down on the small end where the area is minimized?