Pumping Helium with a Compressor

This is the setup I use to pump Helium into my tanks. I did not invent it; Reinhard and Michael told me how to do it. This technique is very useful when you have a limited pressure (say 150 bars / 2200 psi) in your Helium supply bottles and you need to pump, say 200 bars / 2950 psi into your diving tanks.

There are only 3 parts to the system:

An old style regulator;
A pressure gauge + fittings;
A hose that fits tight on the regulator outlet.

It is good to invest in a decent quality gauge so that you can get the supply bottle almost empty without running too high a risk of having the compressor suck the bottle totally dry and working beyond that point.

I put a bunch of duct tape around the holes in the regulator and on the inlet hose. The idea is to dampen as much as possible the vibrations on the diaphragm of the regulator. This will increase its life.

The purge valve is not necessary. If I built another one of these I would leave it out.

I found there was no need to use hose clamps around the hose. It is tight enough on both sides. I after I boost helium into a tank I always oxygen analyze the resulting mix. If the hose was not tight the compressor would also suck some air in and I would detect some O2 with the analyzer. This has never happened so far.

The compressor I use is a Bauer Utilus. Not a monster but it works.

The flexible hose connects very well on the first of the three PVC tubes provided by Bauer. No need for a hose clamp.

I first start the compressor, then connect the hose on the PVC, then wait one minute for the Helium to be the only gas that is being compressed, then I connect the tank to be filled.

I have boosted other gases than Helium with this system: trimix 10/70, 18/40, 35/35, 50/35 and even argon, though not more than 20 minutes in a row so that the compressor does not heat up too much.

There are many designs out there for such a system. This one has very few parts and connections so it is easy to transport, unlikely to fail and it works.