Fill station pressure gauge connection

[stiebs]

I'm putting together a bill-of-materials for my fill station, considering predominantly Parker or Swagelok. I have a WIKA 100mm for my fill gauge, but have hit a block with how to connect it.

The gauge inlet is a G1/2 BSPP male connection. Easy enough.

The Parker part number is 4FSC8GC, which also requires a profile sealing washer (M30204-SS). However the spec sheet tells me that the sealing washer is rated for maximum 280 bar, which isn't ideal if I want to fill 300 bar cylinders.

The Swagelok part number is SS-400-7-8RG, and they just have flat gaskets, not profile seals - not really an issue, since its a compression fitting so the profile seal is not required to ensure correct orientation - but they're only available in copper or nickel. I wouldn't have thought copper or nickel ideal for a breathing air system. Or is it OK if its just the gauge gasket?

 

[happy-diver]

Hey mate google, m3 screws

Tungum!

 

[Tanks A Lot]

I wouldn't think twice about using a copper gasket. Copper is ubiquitous around breathing valves and fittings. From gaskets of packing nuts, such as used by Thermo, Sherwood, SoS and others, to the literal body of the valve or fitting, which is often made from brass (main component copper).

The only issues I'm aware with regards to copper is that it can cause metal-fume-fever, but I have only ever seen it mentioned with regards to copper dust. I see this as a non-issue in the used application. This leaves aside the super rare copper allergy, which should also be a non-issue on a static gasket.

In short, I wouldn't worry about it at all and go for a copper gasket, which are proven workhorses in the industry.