Check Valves

[spectrum]

This thread reminded me of something I have wondered about. Why don't fill whips have check valves?

Set asside mixed gasses and inadvertent blending to tanks or banks.

I come into the shop with 4 cylinders with 500 PSI, 800 PSI, 1500 PSI and 1800 PSI remaining. They get hooked to 4 whips, cylinder valves are opened and whips are opened. The supply is not even opened yet. The higher pressure cyinders blow down into the lesser ones and I'm in a fast fill situation before we start.

Now the cylinders that were fairly full now need major fills and the lesser ones have a head start but are already warm.

On top of that the shop needs to do all of the higher pressure work since the energy in the higher residual fills was squandered.

Wouldn't it make sense to have check valves in each whip valve assembly? That way there would be no cross feeding and everything would fill on the pressure rise. Maybe some do but none of the ones I have been around seem to.

Pete

 

[Randy43068]

I think some of them do.

 

[skippy31]

This may not be so much of an issue if all the tank contain the same gasses. If you are topping off tanks that have various mixes in them then the check valves are very important.

Another consideration is that you don't know where the gas that is in the tank has come from. It could be the tank was previously filled by someone with a failed filter setup and there is bad air in the tank that is now going into some other customer's tank.

Basically check valves are a very good idea on each fill whip.

On my home setup I only use one check valve with two whips, but then I'm careful to not transfill two tank into each other. If I'm filling anything with mixed gas I only use a single whip at a time.

Skippy31