Wanted: Sphere Pressure Tester

[Dieselman]

The sphere tester looks a splendid piece of kit. How do you operate it?

I suspect the knob to the right in the below photo is the gas supply valve.

[David Hallworth]

The argon cylinder was just put on the trolley as it was easier to move it on the trolley as it has wheels! The only reason for the 6 foot cylinder is because it's the only one air products who my account is with supply. I'd need to get an adapter for the charging rig to use the Argon cylinder as that has a quick release adapter for the welder whereas the charger has a bullnose type connector.

The sphere pressure tester is operated by pumping the long lever until the pressure gauge stops climbing, once it's stopped climbing I believe that's the pressure in the sphere.

David.

[xmexclusive]

Hi David

The sphere tester is good and easy to use.
I have only found a problem with a few spheres with proud weld metal close to the threads.
The sphere tester has a raised lip to avoid LHM spillage.
If the sphere has proud metal it fouls the lip and fails to seal.
To test any spheres like this I use a CX sphere extender.

John

[David Hallworth]

Do you happen to have a picture of your CX sphere extender, John?

Thanks,

David.

[xmexclusive]

No pictures but if you send me a PM with your address I will post you one.

John

[White Exec]

The sphere pressure tester is operated by pumping the long lever until the pressure gauge stops climbing, once it's stopped climbing I believe that's the pressure in the sphere.

A very neat unit.
That technique - watching for the needle to stop moving - is pretty much the same as as the Tecnosir 720, where you open the re-gas valve gently, and watch for the needle to slow/halt in its upward movement - and that's the sphere pressure.

[Dieselman]

Picture of DS sphere extender in use.

[Jan-hendrik]

The sphere pressure tester is operated by pumping the long lever until the pressure gauge stops climbing, once it's stopped climbing I believe that's the pressure in the sphere.

A very neat unit.
That technique - watching for the needle to stop moving - is pretty much the same as as the Tecnosir 720, where you open the re-gas valve gently, and watch for the needle to slow/halt in its upward movement - and that's the sphere pressure.

My tester uses compressed air.

[David Hallworth]

Well I decided I'd do the job properly and use the right gas so I got myself a cylinder of Nitrogen from Air Products this afternoon.



One side of the regulator shows the pressure in the bottle, the other side shows it in the sphere:



To pressurise the sphere you open the big black tap on the bottom of the regulator that you can see in the first picture. This lets the gas into the sphere. The instructions say you add 3 bar to the pressure required. When you've reached the desired pressure you wait for 1 minute for the sphere to be pressurised. Once a minute it up you close the black tap. I was recharging an accumulator which should be 62 bar so I topped the sphere up to 65 bar.



The brass screw on the side is used to reduce the pressure in the sphere to the correct level:



Once you've set the pressure you tighten the valve onto the sphere and release the charging rig and put a green cap over the end of the sphere.



The instructions for the recharging rig state "NEVER RECHARGE A SPHERE WITH LESS THEN 15 BAR OF PRESSURE". The accumulator that came off the CX was reading 8 bar so I threw it away. I went through the massive pile of old spheres I've got and found the accumulator sphere I took off my Xantia Activa last year. When testing that it was at 45 bar. After checking, all accumulator spheres are the same so I recharged that one and fitted it back to the CX.

The pump now sounds much happier and the regulator is now ticking every 30 seconds again rather then every 3 seconds before. Will try and get the rest of the CX spheres done this weekend and then the two XM's and Xantia at some point. I noticed that one of my old spheres in a box has a recharging plug on it. The instructions say they are only to be used once though so not sure if it's worth recovering or not.

At first I couldn't get the sphere to take gas. However on closer inspection the valves aren't actually valves, they are more akin to bungs. There's no direct path through them for the gas. Reading the instructions that came with the rig says that you fit the "valve" to the sphere without tightening it, then you place the recharging tool on top of the valve and gently tighten it down onto the sphere. There's an o-ring in the charging rig that creates a seal around the sphere. When you open the regulator there is a seal created around the sphere as the valve pulls away from the sphere and the rig is pulled towards the sphere. You can then hear the gas flowing into the sphere. Once the sphere has gas in it you tighten the screw on the back of the recharging rig and that tightens the valve onto the sphere which creates the seal and stops the gas escaping.

As these are just bungs, there's no real reason that I can't make more of these on the lathe when I have time.

David.

[White Exec]

David, that's fascinating detail.

Interesting that the widgets are just threaded bungs, which allow the gas to enter while not tightened - hence the advice for a 1-minute pause in the procedure.
That also tells me how new/original Citroen spheres are first factory charged; not obvious until now.

Are the Citroen valves for your tool still available from Citroen? Could an original stopper be used/adapted - there's plenty kicking around!
Could you post some close-up photos of the valve/bung itself?

Great stuff,
C.