Bank System Fill Questions

[v101]

Hello SB members, didn't know if this was the correct area to post this... but figured it related to tanks, so figured i'd post this here...

I am looking to purchase 4 bank bottles, to hold enough gas for me to do some remote fills, when I am diving. maybe 4500 PSI or 5000 PSI bottles.

I typically dive w/ 2 HP Steel 100's or 2 LP 85' since diving SM we dont ever suck them down too much. so the bank system only needs to top off the gas from 1800-2000 to 3500.
Someone we dive w/ has a 4 bank system of 4500 PSI cylinders, and this setup provides enough air, for 3-4 days of diving, which is what I am looking to do, vs steal their gas.

My question lies w/ getting air fills on these tanks. I just bought/ordered Vance Harlow's book Oxygen Hackers Companion so perhaps some of these q's will be answered in the book.

I am looking to get the fills done at a local gas supplier vs a LDS, to save $$ the LDS can fill my bank system, but it will cost more than @ the Local Gas Supplier. Here lies my questions:

Does anyone get their bank systems filled @ a Local Gas Supplier?
If so can you comment on the fills, the costs, etc.?
Are you able to get custom EAN blends from a gas supplier?

The next phase of this will be to eventually buy a compressor and build a nitrox stick and do my own blends, but for now I am looking to just get the bank system, and then get my fills to take w/ me.

Appreciate your comments;

 

[oly5050user]

would it not be easier and less expensive to simply own more tanks and fill at LDS?As to EAN from gas supplier I very much doubt it .

 

[tbone1004]

I'm going to go out on a limb here and say that you may be getting in over your head.... You are going to be wasting a lot of gas, and I'm 99.999% positive you won't be able to get any sort of nitrox from the gas fillers certainly not custom mixes. With the cost of bank bottles, you may as well just buy a small gas compressor i.e. Rix SA-3 or SA-6 and call it good. Cost $3k ish, and then you can blend to your hearts content with one O2 bottle that will last you months, will be smaller, lighter, get you custom blends, and much more versatile. Most shops also don't have the ability to fill to 4500psi, so you'll never get the banks to be full if you take them to a shop, you MIGHT get 3800psi out of them. Which drops cubic footage from 444 down to 375.

The not sucking them down too much here is your problem. Cascade filling is not good for bringing tanks up to full pressures in volume. You start getting short fills really fast.

Assuming you have 4 4500 psi bottles pumped up full. and each tank is going to service pressure, you'll probably be able to fill all 4 tanks to service pressure 5 or 6 times ish.

These 4500psi cascade tanks weigh close to 200lbs each when full, so keep that in mind for "portable". You are pretty much restricted to putting them semi permanently in or on a trailer of some sort. An Oxygen T bottle weighs about 100lbs when full and the Rix is a little less than 200lbs with the gas motor I think. Haven't weighed mine, but it can easily be lifted into the back of a pickup or SUV by two guys, one if you're big. So maybe 150lbs. You can get a Rix for well under $3k, and renting T bottles is cheap, you're going to see real cheap blend sticks in the oxyhacker manual, and with the cost of cascade bottles, you're much better off just biting the bullet and buying a compressor.

 

[Doc Harry]

Good to talk with you on the phone v101.

Any other questions about a home fill station, just give me a call.

 

[fire_diver]

Like the others said, you are putting the cart before the horse. You need to get the compressor then get the bank bottles. Gas suppliers won't do custom EAN mixes.

In case you aren't familiar with how to use a bank of bottles, you don't use them all at once. You fill your scuba tanks off bottle #1 until it can no longer fill to max pressure you want. Then you put in what you can from bottle #1 and top off from bottle number #2. Keep doing that until you are topping off from bottle #4 (or whatever your last bank bottle is). This is about the time you re-fill your bank system from the compressor.

 

[v101]

Thanks for the responses.

I did locate a compressor, and its looking like that is the route I am going to go. I got off the phone w/ the Local Gas Company and their prices to get Grade E air fills were 24 bucks for a T size bottle, but the PSI wasn't that great, I think it was 2600 PSI, so this means I can't even top off my HP 100's, to a full fill, not what i had in mind. about the EAN blend, he ran the #'s and it's going to cost 98.00 for a custom EAN blend per tank!!! outch... i will pass on that option!!!

I checked around some and the compressor I am looking at purchasing is around 3K for a unit that can pump to 4500 PSI. I located some used 4500 bottles for around 350/each, which I feel w/ a fresh hydro on them, is a decent price.

the idea of hauling them in my truck is option 1, option 2 which i am leaning towards is getting a trailer and just hauling them in the trailer.

So far in the past few days I've learned a lot, and the help from all here, is very good. will keep everyone posted to the progress.

---------- Post added September 18th, 2014 at 06:43 PM ----------

Good to talk with you on the phone v101.

Any other questions about a home fill station, just give me a call.

Yes! It was very good conversation, thanks again for your suggestions and help!

---------- Post added September 18th, 2014 at 06:46 PM ----------

would it not be easier and less expensive to simply own more tanks and fill at LDS?As to EAN from gas supplier I very much doubt it .

This option does work, but the fill station where we dive @, can't ever give a good fill, and its a LONG time to wait for a fill... its frustrating and myself like others are to the point where bringing some fill bottles w/ us is easier than dealing w/ the drama and frustration of taking a Long time to get a bad fill...I've done what you suggested and this does work ok, bringing more tanks w/ me but get them filled to the blend of EAN I want before diving, I can get a good fill in the tanks, and it works ok, however now I have less tanks as I've sold several of my LP tanks. but good suggestion...

 

[spectrum]

I forget what the DOT threshold is for transporting bulk compressed gasses but depending on the size of said cylinders you could be getting on the radar screen.

Pete

 

[Doc Harry]

I forget what the DOT threshold is for transporting bulk compressed gasses but depending on the size of said cylinders you could be getting on the radar screen.

Pete

I think it's > 1,000 pound

 

[fire_diver]

That's 1000 pounds of product, not weight of product and container. This means he could transport 62 K cylinders of compressed air and still be under the 1000 pound threshold.

 

[v101]

I think it's > 1,000 pound

Yes this is correct its 1000 LBS from my calling around and verifying this. Under 1000 and your ok.