3kpsi Nitrogen tank feeding a hand pump 20+ psi? safe or asking for trouble?

[joel w]

For the last few weeks I have been feeding my benji hand pump low pressure nitrogen from a standard 5ft tank.  I have read where people do this with low pressure air from a compressor with success so I figured nitrogen would be fine also (until I read about failed regulators)

Since it's low pressure 20+ psi (50psi is to hard to pump), I figure its pretty safe as long as the regulator does not fail.   If it does fail, I would like to have a weak link some where in the line before the pump that won't hurt me.  Any ideas??  I do have a 3/4" heavy brass 70psi blow off valve from a steam project that may work well?

I have mentioned it here in a few posts but no one has really made any comments on this idea either way??   That made me figured it might be some what safe because if it was too dangerous I am certain some of you would have jumped all over it to stop me.   

Am I the only one doing this?

Edit: Also, I have used standard nitrogen regulators for many years and I have never had an issue with one yet?  Is it the larger 4500-6000psi regulators that fail?

[Addictedtoair]

Hello joel w,

When you say "standard five foot tank" are you talking about the 6000 psi tanks??!

I have not heard of anyone doing this and it seems to me that it could not be safe.

That's just my opinion of course. High pressure air is nothing to just mess around with if you are not sure of what you are doing.

In fact, you need to be sure everything will work right before you open the first valve and start to release thousands of pounds of pressure. Scary...

Please be safe.

Brett


Edit: You had not put down the fact that you have used regulators in the past when I posted. But regarding the original post I still hold to what I said.

[joel w]

It's a small 3000psi tank filled to 1800psi.   My main goal is safety and then it's getting dry air in the gun, also kinda safety related (earlier rust issues).

Sorry for the edits , Thanks Brett 

I think I might be confusing HPA regulators w/ burst disk failing with nitrogen tank regulators? If so then my bad.

Anyone ever have a 3000psi nitrogen tank regulator fail? Right now I have a two inch length section of 80psi rubber hose as a weak link but the blow off valve seems a much safer route.

From what I read here, when these regulators fail, they fail to the atmosphere and not down stream so I think I am ok.   

There is "creep" failure also which is downstream but I would feel that in the pump when it got too hard to push down.

http://www.harrisproductsgroup.com/en/Expert-Advice/Articles/Regulator-Life-Expectancy.aspx

[willbird]

I had a look at grainger, they sell a pressure relief valve you can set to 25 psi.

http://www.grainger.com/Grainger/CDI-CONTROL-DEVICES-Adjustable-Relief-Valve-6D915?Pid=search

If you have any doubt I would put one of these inline, or 2 or 3 if that works out to a minumum order somewhere to get "free" shipping". They run around $8. It will flow 80 CFM which is a LOT really, one should be enough.

Bill

[joel w]

Thanks for the link Bill.   Better to ask, look stupid and be safe then not ask, be stupid and get hurt.   

If anyone is wondering why I went this route??? It's because I am cheap or as my wife says "frugal".  lol.. But seriously, it now takes only 20 good pumps to fill the Mrod from 2k-3kpsi.  A bigger/heavier person could probably do it in 12 pumps with a little higher psi but I feel that may be the limit of the pump. I am only at 165lbs so this works for me.  I can also use every bit of the nitrogen in the tank.  Regulators can be had at under $60 instead of $400-500 for the higher PSI regulators and the tanks are cheap also.  My main reason was just getting dry nitrogen into the gun instead of dripping wet air.

Be safe!

[eelect]

I used to do it all the time. But what I did was fill a 3 gallon tank and that would feed my pump. Tank would have a regulator on it. I'd fill tank to 125 psi and it would go for 3 fill ups with Mrod

[joel w]

Nice automation!  Was the 3 gallon tank for safety or portability?

Thank you.
Edit: fixed

[eelect]

More for portability if anything

[venxxxxx]

Been feeding my benji pump with up to 40psi from a small compressor. WOrks great so far.