Question How to accurately fill 1800psi tanks?

[n1023]

Got some old army tanks with 1800psi service pressure but every compressor I’ve used fills at ~2200psi.

To be clear, I’m not talking about the final pressure being 2200. I mean the gauge on the fill whip shows 2200 throughout the fill until the pressure reaches >2200 then it starts going up.

Best case, wait until the needle starts moving past 2200 and get a slight overfill?

 

[Bowers]

What compressors are you using?? Ive never had one that wont show lower pressures.

 

[n1023]

Nuvair/Coltri mini-tech. I haven’t used my Bauer jr in a while but I believe it’s the same.

 

[TravisD]

Sounds like the gauge is reading before the PMV (showing the output of the final stage). Adding a gauge the the fill whip would let you see cylinder pressure. If you're taking these to multiple places for fills, you could probably set up a short whip or adaptor with a gauge or even a settable regulator to go between the whip and cylinder valve.

 

[n1023]

Sounds like the gauge is reading before the PMV (showing the output of the final stage). Adding a gauge the the fill whip would let you see cylinder pressure. If you're taking these to multiple places for fills, you could probably set up a short whip or adaptor with a gauge or even a settable regulator to go between the whip and cylinder valve.

That makes sense, I do have a banjo adapter with an spg that I could use. Seems like it would do the same thing?

 

[TravisD]

I guess you could re-use things if they're not otherwise needed, but depending on what fittings you have, it might be cheaper to pick up a cheap non-Submersible gauge rather than all of the adaptors needed to make your existing stuff works. You can get a 0-5000psi gauge for like $20 with 1/4NPT. It's likely (but not guaranteed) that the fill whip is already 1/4NPT so a Tee fitting would be basically all you need to add it in-line as part of the fill whip.

For something portable, assuming you're using Yoke valves, you're probably looking at some sort of Yoke clamp -> Tee+gauge (maybe this is where your banjo fitting could go?) -> yoke block. (I have no clue how your banjo fitting works in this case, or what it's specs are...)

 

[n1023]

The compressors belong to the county I work at, so modifying them outside of regular services is likely not allowed. But here’s my banjo spg setup, I use it for my vintage double hose reg. It sits between the tank and first stage, or tank and yoke block in this case.

 

[TravisD]

If it fits and doesn't leak, seems like it should work.

 

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[rhwestfall]

I would build something:

If DIN a whip - female DIN socket to a tee with gauge and yoke clamp on the other leg (remember a bleeder though you should have one on the whip).

If yoke whip, female yoke to same as above in place of DIN..