filling a dive tank with an air compressor

[MC]

I have a Brownie Hookah that produces 18cfm (it's an older unit-the newer units only produce 12 or 9cfm). Reading some stuff, I noticed tank fill stations that cite filling dive tanks at a lower cfm.

What I was wondering is could I use my Hookah/compressor to fill my dive tanks? Why/why not?

 

[Scared Silly]

I know nothing of the units but I suspect that while they deliver 9-12cfm it is at a low psi - perhaps around 150psi which the intermediate pressure of most first stages and what most second stages require. As such, you aint going to get much gas into your cylinder at that pressure.

 

[Bob3]

 

[dannobee]

I see yours and I raise you one.


Actually, irrespective of the lack of coalescers/separators and the filters, the problem is that most scuba compressors pump to 5000 psi. Hookah compressors only pump to intermediate pressure (~150 psi)

 

[MC]

yep it's a psi issue. Kind of found the answer after I posted the question.

 

[MDJ1016]

Correct me if I am wrong but you would need more pressure to “push” air into the tank, yes? My basis is this- I have a tank transfer hose and if one tank is at 500 PSI and the other is at 3000 PSI it will transfer from the higher PSI tank to the lower PSI tank until both are relatively close. Thus to fill a tank to 2400, 2650, 3000 or 3415 (think that is what an HP is) you would need at least that pressure on the fill source?

Anyone that did better than my “B+” in physics I would appreciate a little help closing the gap here!
Of course I am just a numbers guy, maybe I am wrong.

 

[MDJ1016]

I should add, that is consistant equal pressue at that....

 

[Damselfish]

Correct me if I am wrong but you would need more pressure to “push” air into the tank, yes? My basis is this- I have a tank transfer hose and if one tank is at 500 PSI and the other is at 3000 PSI it will transfer from the higher PSI tank to the lower PSI tank until both are relatively close. Thus to fill a tank to 2400, 2650, 3000 or 3415 (think that is what an HP is) you would need at least that pressure on the fill source?

not exactly. Transferring between tanks is different because the pressure of the source will be dropping. Not the case for a compressor.

 

[MDJ1016]

I have a great LDS, and will be there this week. I will ask the owner; he is always a great source of information.

 

[captain]

A compressor will provide pressure up to it design rating. If it's design rating is 5000 psi than it can fill any tank up to what ever pressure the tank is designed to hold ( 2400, 2650, 3000, 3415, 5000 etc).