Designing a variety of gate valves for use within a Fuel Metering Unit. Usually we use O-rings for sealing purposes between sleeves and bores.
I'm currenting looking to see if there are any viable alternatives to O-rings, mainly to avoid stepping in the sleeve diameter when a number of seals are required. (Freeze fitting being a non-preferred option).
Typical operating conditions:-
Temp Range: -53 degC to 180degC
Pressure: 800 psi differential
The sleeve will be a hard anodised Al alloy
For the temperatures stated you could use spring energized PTFE lipseals. The main disadvantage of this type of seal is :-
1/it is difficult to fit into a conventional oring groove and a redesign of the major components is necessary.
2/ They are more easily damaged than conventional orings.
3/ more expensive than orings.
The big positive is that they are less likely to be affected by the temperatures and line medium.

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