Haskel Mini Sport for filling AL40 / AL80 Deco Cylinders?

[BjörnBear]

Hi All,
I know the Haskel Mini Sport is well liked for filling small rebreather cylinders, but does anyone have experience using this to fill AL40 or AL80 deco cylinders with oxygen? I'm trying to determine if this will work for the occasional fill (3-4 cylinders per year) when I can't get a shop fill.

I do have a small compressor (3.5 cfm) and several HP tanks to use for drive gas.

 

[tbone1004]

The biggest issue with the baby booster is it has a fairly low boost ratio at 25:1. Since it has a max inlet pressure of 150psi you have a theoretical max of 3750psi, but a 1st stage is typically 135->3375psi, and most air compressors are 120psi->3000psi.
This is fine, but don't expect full fills from it. The advantage though is you can just leave it until it stalls since you are not at risk of overfilling anything.

These pneumatic boosters are also pigs when it comes to drive gas so I would not bother wasting the time and money on using scuba tanks to drive it as you will not be able to fill an al40 or heaven forbid an al80. Depending on which small compressor you have *not sure if it is scuba or low pressure* then it just takes quite a long time to fill anything large which will likely be several hours for the larger bottles depending on what they equalize to from the supply gas.
If you have a LP compressor, then you do need adequate filtration for it in order to run the baby booster without destroying it so make sure you have high end filters on there to feed it clean and more importantly dry gas. If scuba compressor then you're just spending about 5-6x as much to run the booster than you would off of a shop compressor but you don't have to invest about $1k to sort out a proper system to keep it happy.

 

[broncobowsher]

Yes, it does work. Just get ready for a long evening. Hope your shop compressor is continuous duty rated.

I've done it a couple times now. Thankfully bail outs rarely require filling and barely a top off every once in awhile. I have a large 2-stage IR compressor that is continuous duty rated and it will run more than 50% duty cycle. I believe I am rated at about 11 CFM and the 2-stage will get the high end of the operating pressure needed. Guessing I am running about 6 CFM, and I run my booster on the slow side. Your little 3 CFM will be running non-stop and running the booster really slow. The HP cylinders for drive gas, that will be a joke. I go though one of those to do a parking lot fill on the rebreather cylinder. You would blow a dozen of those.

It does help if you are starting with a full K-bottle. The job is halfway done by the time you finish with the fill whip.

 

[BjörnBear]

Thanks guys. The compressor is an HP scuba compressor and I have a set of HP 117s. My idea was to hook up and run the compressor on one valve of the doubles, and hook up the booster to a regulator on the other valve so the compressor can fill the doubles as they drive the booster. Sounds like this might work for a small top off in a pinch, but not a great option for filling from empty.

 

[mdwalter]

Thanks guys. The compressor is an HP scuba compressor and I have a set of HP 117s. My idea was to hook up and run the compressor on one valve of the doubles, and hook up the booster to a regulator on the other valve so the compressor can fill the doubles as they drive the booster. Sounds like this might work for a small top off in a pinch, but not a great option for filling from empty.

Why would you use a booster to fill from empty? It would always be a top-up. If you had 2 half empty tanks with the same mix that you wanted to get all into one tank so you could have a single full tank for deco or bailout or whatever. If you had a half full AL80 and an empty AL40, it would make no sense to try to boost the gas into the 40, just dive the 80. Even if you have a scenario where you have 2 or 3 partially empty tanks you want to make into 1 full tank, you would not boost all 3 into an empty 4th tank, but rather boost 2 of the 3 into the third. If you start from an empty tank, you're going to use your compressor, not a booster.

 

[lermontov]

youll need to get cunning about how you mix your gas minimising boosting time - I dont have an air compressor so i just premix my o2 and helium and get it air filled at a shop to top up and get the mix i want -you can use shop compressor to use as drive gas if use a dryer -you can make a dryer up pretty cheaply and use bottled gas to finish off

 

[BjörnBear]

@mdwalter and @lermontov
Thanks for your input. To clarify, am looking for real world experice specifically with the Haskel Mini Sport booster and time it would take for creating simple EAN or 100% O2 deco gasses.

Let's use a hypothetical scenario. I have an empty AL40 want to create an EAN80 mix. I have a partially used industrial cylinder of O2, and after equalizing that into the AL40, I have roughly 850 PSI of oxygen in the AL40. To make the EAN80 mix, I now need to boost roughtly another 1370 PSI of O2 before topping with Air to 3000 PSI.

Assuming a steady supply of 150 PSI boost gas from HP scuba tanks with a regulator attached, the question I was hoping to answer is how much time and boost gas would a Haskel Mini Sport require to boost that additional 1370 PSI of O2 (to get from 850 to 2220 PSI O2) into an AL40?

From @broncobowsher experience, it sounds like quite a bit of time and gas; though I'm not sure if he was filling 80s or 40s.

 

[broncobowsher]

I have done both 40s and 80s. In 3 years I have done the 80 twice. Once for an initial fill, again after a training dive. Couple top offs that I don't count. 40s the same way.

Last year a friend wanted to buy a spare 40 I had and wanted it filled with 100%. I didn't time it. Like you describe, equalize off a used industrial then start pumping. If I had to guess, probably an hour.

 

[lermontov]

if you go to DGX they have them for sale and I think they have specs for boosting times -but more importantly there is a ratio of supply to pumped tank fro 02 that shouldnt be exceeded due to the fire risk ( i think 5-1) -sorry theres no short cuts to speed things up -in fact its not a good idea to fill fast

Haskel Mini Sport Booster

The Mini Sport Booster from Haskel is designed for diving applications that demand performance, reliability and safety at an affordable price. The oil-free Mini Sport Booster is a compressed air driven, air cooled, non-lubricated, reciprocating piston, single stage type

www.divegearexpress.com

 

[broncobowsher]

When you are sucking from a low supply bottle into a nearly full dive bottle (filling O2 for example) the efficiency of the booster drops off. You blow a lot more drive gas. This is where a good shop compressor is handy. I don't care. I have an unlimited supply of drive gas.