Argon cylinder / no valve / 1st stage

[Agro]

An argon cylinder normally has a lot of "valve + 1st stage" and little "cylinder". So I decided to reduce it to the max, no valve anymore. I made an adapter between cylinder and 1st stage. To reduce the 1st stage's volume and weight I took an Apeks Flight.
The result is what you see.
The cylinder must be filled by its HP port, therefor a non return valve is needed. First I tried Scubapro High Preasure "Quick Disconnect" Connector | #154094188 but this did not work at all, the inner sealing came out of the scubapro connector. This quick connector is NOT made to fill a cylinder, so no accusation.
I produced my own non return valve, this is the knurled part. You fill it by its M5 thread. Inside are parts of Poseidon Xstream regulator: cytel seat and ball.
The cylinder is 1 lt 300 bar.
Works fine so far.

 

[DiveClimbRide]

That's quite impressive, congrats! I assume the adapter is tank thread to din?

 

[TravisD]

If a hose comes apart, is there any way to shut it off?

 

[Bald Wookie]

Strongly suggest an OPV for the 1st stage seeing as its permanently connected and you have no second stage that will leak by if the IP pressure of the 1st stage gets too high

 

[Agro]

No, the adapter ist not tank thread to DIN. I took away the 1st stage's DIN parts. The Apeks Flight has a M19.8x1.27 thread, so the adapter has this thread and the M18x1.5 cylinder thread.

No, if I have any dammage, for ex. broken hose, I loose all the argon. As the cylinder is very small and I can not reach the cylinder very well I don't think I could stopp the total loss of gas by closing a valve anyway. I guess cylinder is empty before I close the valve. And even if I could save some argon by closing the valve I can not use it anymore because the hose is dammaged. Having no valve seems to be a negativ point but the more I think about it the less I think it is a real disadvantage.

The OPV is fixed on the 1st stage you can see it on the pic. Yes it is strongly recommended to use a OPV.

 

[Agro]

FA is filling adapter. I will post some details about it later

 

[rboban]

Great job... which M18x1.5 cylinder is used?

 

[Agro]

This is a 1 lt 300 bar steel cylinder. But you can use any M18x1.5 cylinder.

 

[-JD-]

I'm not sure if there is enough meat in the HP port of the reg body to accept a 1/8" NPT, but if so, you could use a standard QD PCP airgun fill like this:
Deluxe SS Male Foster Fitting with Male 1/8 NPT and Removable Check Valve

 

[Agro]

JD, this looks great indeed!
The 1/8"NPT is slighty smaller then the HP port's UNF7/16. But there is not enough difference to put an adaptor in between. So I guess I will reproduce the fitting's body: outside thread UNF7/16, inside the check valve. The Foster fitting (I think this is the coupling) I will leave away and make an even shorter filling adapter.
The great advantage of this check valve is the fact that it is located inside the thread which makes the whole thing much shorter and also smaller in diameter.
I hope I can get this Foster fitting in Switzerland or at least in Europe.