Is my bottle stuck shut? 2

[martin seymour]

Like Foxx I'm having trouble with my SGS Argon cylinder tap.
I couldn't hear any gas coming out of the torch. I took off the regulator and unscrewed the cylinders tap and I thought the cylinder was empty - already?.
Pressing in the little 3 sided piece you can see in the middle of the cone - gas came out under pressure and didn't stop, Screwed down the tap again and it stopped, open it up again and nothing until I repeat the previous - it appears this little valve thingy is sticking - should it do this?

 

[voipio]

When the main cylinder valve is closed, what happens when the tri-winged part is depressed inwards? Does it move, and does it then return, when the "pressing in" device is removed?

I've never taken one of these apart but, from the behaviour you've described, it might be there to stop excessive gas flow from the cylinder in the event of e.g. a regulator component rupture. If that's the case, then there ought to be a spring pushing it towards the inside of the valve i.e. away from the camera viewpoint so, normally, it shouldn't move when inward force is applied. But guessing here, really.

The other possibility is that the tri-winged part is a residual pressure device, to stop the cylinder pressure from dropping below a certain value, in order to prevent contamination of the cylinder's contents. preserve the integrity of the cylinder contents, and prevent contamination of the cylinder internals by anything, liquid or gas. Poking it with something might be unseating the residual pressure valve.

 

[martin seymour]

Thanks for the reply Voipio , This morning I took the gas bottle back to my local distributor who told me the cylinder was empty but they'd look into it .
When I got home I called SGS themselves and explained the situation and they told me the valve retains a small amount of pressure to stop moisture entering and contaminating the cylinder. Fair enough but why when you press in the Schrader type valve doesn't it pop back out? They're sorting me out a replacement cylinder now!

 

[Agautosport]

I am fascinated by some of the advice being given here. SGS Gases use residual pressure valves, as do most reputable companies, that hold a very small amount of pressure in the cylinder when it is empty in order to prevent contamination.
These valves are produced by a company called Cavagna and are “ probably the best valves in the world” ( acknowledgement to Carlesberg)
It really isn’t a good idea to poke things into the valve or disassemble the valve if you think something is wrong with the valve.
Just take the cylinder back to the distributor and ask them to contact SGS Gases. We can then deal with the issue.
Alan SGS Gases Ltd