Building a Air Bank???

[Iguana Greg]

Hello-

Thanks for having me. I will be on the compressor, ect. forums as I just took a job at a resort and they own a dive shop. They want to build an air bank and have read of two theories, Cascade System and "Marrying" the tanks method. So, I'll be hoping to get some good input.

Thank you for your time an support.

Greg

 

[Iguana Greg]

Hello again-

I have 4-4500psi bottles to use. Looking to fill perhaps a couple tanks at a time. What is best for conserving air? We need to run the compressors as little as possible. I have researched a bit today and I hear the cascade system is the most efficient but takes a little longer to fill a tank duo to starting and stopping 3 - 4 times.

Any insight would be greatly appreciated...........

Thank you for your time and response.

Cheers,

Greg
Engineer
Little Corn Island, Nic

 

[WVMike]

Hello again-

I have 4-4500psi bottles to use. Looking to fill perhaps a couple tanks at a time. What is best for conserving air? We need to run the compressors as little as possible.

A fill panel would be a good addition. I would connect two of the bottles together and use them for the volume filling and use the other two as singles for high pressure top off.

 

[Peter_C]

That is a small cascade. I know I have the exact same setup. I ran my 10cfm compressor for two hours the other evening to fill it back up for a time reference. I pump the banks to 5,000 psi and they cool to right around 4,550 or so.

We fill pretty much nothing but big tanks though in the HP120-HP130 range or double 100's and pump them up pretty high, so the top banks get killed quickly. Only pumping 80cf tanks to 3,000 psi would make it go much further. You could also add in a couple of low pressure banks for the volume of the fills and to ease the compressor use at higher pressures.

A fill panel would be really nice, but a well lubed valve is easy enough, and cheap! With a system of the size we have cascading it is the way to go. Unless you have 10+ bottles and a booster.

 

[Superlyte27]

Cascade is absolutely the way to go, regardless of a booster or not. I'll give you an example.

A few weeks ago when we were teaching Boy Scouts, we had 28 bottles to fill after class. We have a 9cfm compressor and 5 4500lb bottles for our bank. The first day, I cascaded the 5 tanks and we filled 28 bottles in just over an hour. Like 1:17.

The next day, we filled 28 tanks with all 5 4500lb bottles open, using our haskell. It took more than 5 hours to finish the fills. The first few tanks filled quickly, then the bank dropped to about 3000lbs. The haskel had to take up all the slack to pump the bottles up. The haskel is boosted by the bank pressure, and it's very wasteful. The more we use the haskel, the more air we waste. I cut 4+ hours off the fill times on 28 scuba tanks simple by cascading the tanks. I opened the first tank, equalized, opened the second tank, equalized, opened the third tank, equalized, then hooked up empty scuba tanks. Open the first tank, equalize, open the second tank, equalize, open the third tank, equalize. Notice I haven't even touched the 4th and 5th bottles yet. and I've filled half scuba tanks before I need to open the 4th and 5th bottles.

 

[Scuba Duck]

One of the dive shops I work with frequently here in Hawaii has a Cascade system with about 50 storage bottles grouped into high, medium, and low banks. Its a pyramid system with about 25 of the bottles in the low bank, 15 or so bottles in the medium bank, and 10 bottles in the high bank. When they leave for the night, they equalize all the banks and let the air compressor fill the whole system to about 3700 psi. They also have fill manifolds with 8 fill whips each, that can plug into one another. Hook together 4 manifolds, and you can fill 32 tanks at one time.

Hook up 32 tanks, equalize low bank, then shut low bank, equalize medium bank, then shut medium bank, then (if you need to) equalize the high bank. They can fill 32 AL80 tanks in 10 minutes with no heating problems. The longest part of the process is hooking up and un hooking the tanks to the fill whips.

Your ability to fill lots of tanks in a short period of time is dictated by the size of your storage system. The number of tanks you can fill in one day is dictated by the size of your air compressor.

Fill panels don't need to be expensive, you can use "tees", pressure gauges, and simple valves to get it done. Mcmaster carr is an inexpensive source for the pressure gauges and pipe fittings. GMC or NESS has Mount it to a piece of plywood...

 

[Superlyte27]

Your ability to fill lots of tanks in a short period of time is dictated by the size of your storage system. The number of tanks you can fill in one day is dictated by the size of your air compressor.

QUOTE]


Haha, not true. Go look at Bill Rennaker's place. I'm guessing (it's an educated guess) that he could fill several hundred sets of doubles before having to turn on his compressor. But, in all fairness, his bank is bigger than two of my garages.

Linda told me sometimes they only turn it on twice a week.