Schrader to bsp adapter or similar

[wizardry]

I have a conundrum that needs solving and so far no amount of google seems to be solving it! I have come to the conclusion I am perhaps looking for something that does not exist....

Basically we have some tanks that need air pressure testing (low figures only a few psi needed).

We have a way of getting a threaded schrader valve stem in the tank which I believe is a .305-32 thread (see wikipedia). It was intended this would have the valve core left out.

The plan was then to go to a pressure gauge which seem to be available in 1/4 bsp (or similar).

Then finally pressure gauge back to schrader with valve core in to connect pump.

Either adaptors to do this (valve to bsp) or taps to make your own seem to be almost unobtainable.

Is there an easier way to do this? Have I missed a simpler solution?

Help much appreciated........

[matt nossiter]

If it's only very low pressures that your testing it to and you have a male thread can you not just use a suitable rubber hose to connect the tanks to a gauge and then onto a pump ?

[s2rrr]

I take it the Schrader valve is to allow for pressurising so why not just do away with the Schrader valve and connect straight to the tank from the air supply with a series probably two or three isolation valves with a tee piece to allow for pressurising and depressurising. You should also have some form of safety release valve in case of inadvertent over pressuring. I take it your dilemma is the fact that your supply is a standard air line attachment. You could use standard plug in Schrader air hose connections but you do say you have a valve stem in the tank. I'm a bit unclear as to what you need but there is generally some way of obtaining connections or making them.

 

Be aware that H&SE have limitations on pneumatic testing due to the inherent energy involved should they burst generally anything above 1 bar. Safer with water if that would be possible, which it sometimes isn't.

 

Trying to help but think I'm making matters worse.

 

Bob

[Welly Jen]

If you just need to connect for testing, then how about using the hose and schrader attachment end off a track bike pump? These generally clamp to the valve stem by compressing a rubber ring when the lever is set. You then use a suitable 1/4BSP to hose tail fitting to attach to the other end of the hose.

 

Jen

[dhutch]

I am sure adapters could be made cheaply enough.

But as said, assuming the gauge doesnt need to be detachable, attach it direct to the tank, with and isolation so it can be changed if it fails.

Then again, if the air supply is from an airline, you could have an airline connector to attach it. If the tank is quite small you may need a suitable valve to regulate the incoming air, this could even be a pressure regulating valve. Or at very least, I would like to thing you can get from 1/4 BSP out to a Schrader. Even if just by buying a inner tube, brass 1/4in bsp fitting, and soldering one to the other!!

Daniel

Daniel

[wizardry]

Thanks all those ideas have cleared the mental block!

I was trying to do the lot off one penetration into the tank and a daisy chain of connections.

In hindsight this is only creating more joints to seal with various threads.

Using 2 connections greatly simplifies things. Schrader valve in custom fitting to one and gauge straight in the other......

[s2rrr]

Pleased to hear you are sorted.

Bob