What is the correct name for a metal washer with an inset O-ring. Often used to seal a gas regulator (CO2) onto a bottle of gas.
The idea is that you cannot over compress the O-ring.
Hi Will -- For fairly low-presure applications a "Face Seal Washer" was the American DoD name. For higher pressure applications a "custom o-ring seal" washer was specifically designed. [Mind you,
I have designed "custom o-ring seal" washers to contain 65 ksi pyrotechnic gasses.] -- Lew