Gas Booster Drive Gas Volume

[OceanEyes]

I’m getting a little tired of the long drives that I’ve got to make in order to get fills for the 2 liter HP steel cylinders that I use with my CCR. The only local shop that can reliably supply O2 at sufficient pressure now charges much too much for a fill, ($20.00, as opposed to the $7.00 or so that I pay at more distant shops), and they cannot provide trimix fills.


I’ve done a bit of research and am seriously considering purchasing a small booster, either a Hydraulics International Compact Booster, or, more likely, a Haskel Mini Sport MSB-9000 Booster.


For a variety of reasons, I do not wish to purchase a compressor, so must rely on OC cylinders and a regulator to supply drive gas.


I have been unable to find any hard data regarding the volume of drive gas that the Haskel booster requires. I’ll start with supply gas in steel 100’s at 3,500 PSI, and can probably get a couple of transfer fills without having to boost at all, then boost the gas as the supply cylinder pressure decreases.


Can any of you more experienced souls please provide me with an approximation of the volume of drive gas that I can expect to require to run the booster to fill the 2 liter cylinders?

 

[TrimixToo]

Go find the Haskel software (posted by American Airworks, IIRC) and it will tell you everything...

Note that a small shop compressor with a decent water trap is all you really need to drive a booster.

 

[OceanEyes]

Thank you TrimixToo. You posted a link to that very source recently in a thread started by boulderjohn. I downloaded the file, and opened the Zip and found that the software is only formatted for PCs. I use a Mac and was unable to access the information.

Regarding using a small shop compressor, (which I'd prefer to avoid,) doesn't the Haskel require drive gas to be delivered at a continuous 150 psi and at a reasonable fpm rate? That seems to demand a rather hefty compressor.

 

[RayfromTX]

dewalt has a model that runs at the higher pressures that you will need but I'm not sure if the volume is sufficient.

 

[TrimixToo]

Thank you TrimixToo. You posted a link to that very source recently in a thread started by boulderjohn. I downloaded the file, and opened the Zip and found that the software is only formatted for PCs. I use a Mac and was unable to access the information.

Regarding using a small shop compressor, (which I'd prefer to avoid,) doesn't the Haskel require drive gas to be delivered at a continuous 150 psi and at a reasonable fpm rate? That seems to demand a rather hefty compressor.

A Haskel does not need to be operated at a constant drive gas pressure. Varying the pressure at the pump (via adjustable regulator or valve or both) is how you control cyclic rate and maximum output pressure. For a mini-booster you should not need anything close to the 5HP shop compressor I use for my AG-30. For pumping 02, you will want the cycle rate to be 50/minute *or less* for my booster, and if the drive gas pressure is set to 100 PSI, for example, the maximum O2 pressure would be 3000 PSI. The MB probably has different numbers.

I fired up the software, though, and I don't see the mini-booster in it. You could call Haskel or Nuvair to ask about drive gas requirements, or find a PC (yeah, I know) and calculate what you need from a similar but larger booster's numbers.

For my AG-30, it's impractical to use stored drive air to do anything much. The drive gas requirements are just too high for blending into large doubles and LP72 deco tanks. For a RB, it might be reasonable, but you will need a fairly expensive adjustable HP regulator that might well cost more than a small shop compressor, and you will need air fills to do anything at all. You might look into using T bottles of N2 as drive gas instead, which might cost less, if you are really opposed to a shop compressor.

 

[OceanEyes]

Thank you RayfromTX, and thank you once again TrimixToo for your courteous, insightful and informative response. Thank you as well for opening the files that I could not access on my Mac. I am truly appreciative of your going the extra mile to assist a compatriot who also happens to be a total stranger.

My next step may well be to contact the folks at Haskel or Nuvair. (I have a friend who used to work for Nuvair, but he left that position several years ago.)

There are several reasons why I’d prefer not to have a compressor. The only place where I could put and use it would be in our garage, and my wife has this inexplicable desire to occasionally put her car inside, especially when she returns home during one of our frequent torrential rain storms. Who could have imagined that?

Most of the units that have the capacity to run the Haskel are very loud. I’ll be doing fills well into the night and have no desire to disrupt the neighborhood with noise pollution. Things are bad enough around here with the infernal whine and bellowing of the local leaf blowers, barking dogs, ambulance sirens, and heliport.

Our garage’s wiring may not be able to support the amperage that a suitable compressor requires. Putting a 15 amp load on an already busy 120 circuit may not be tenable. We’ve got a 220 line which we use for our clothes dryer, but any compressor that runs off of 220 will most likely be very loud and probably be overkill for its’ intended purpose.

A compressor is yet another bit of equipment that will require my attention and maintenance. I’ve owned one in the past, and this is not a major obstacle, but one that I’d prefer to avoid. A preliminary search yielded a pair of compressors that may suit my needs, but I’ve never actually seen either of them, an Eagle EA-5000, and Campbell Hausfeld DC040500 both seem to be quiet enough for my domestic situation, and pull low enough amperage to suit the available circuit. I do not know however if they have the capacity to efficiently run the booster.

I’ve got well over a dozen SCUBA cylinders, a pair of which I’d use for supply O2, and another pair for trimix dil; leaving me with plenty to use for my OC dives, air dil, and drive gas. Getting good, affordable, fast EANx and air fills locally is not an issue, just O2 and mix, for which I’ll have to drive and wait a few hours when necessary. I can deal with that a couple of times a month. I’ve also got several reliable regulators, one of which I can designate for use of the drive gas supply.

 

[Wookie]

I can't give you hard data, only anecdotes. I have a mini HI booster, I can dig up the exact reference, but it's the one sold by Add Helium (I'm a dealer too). When filling 2 or 3 liter steels from a full O2 cylinder, it takes a couple of hundred PSI out of your steel hundred. When filling your 3 liter from a nearly empty O2 bottle (getting the last 100 PSI from 400 to 300), it takes nearly the whole steel 100.

My friends in Hawaii have the Haskel version of that booster. They drive it with a home depot 2 HP shop air compressor (the rigid with the 40 gallon tank) at 240 volts (they unplug the dryer and plug in the air compressor) with no issues at all.

Your question is how much air does it take. The answer is "it depends on how much pressure you start with". That's the best I can do for you. If you dive semi-regularly, you will save money buying a shop compressor over getting your hundreds filled.

 

[iain/hsm]

It’s going to be interesting to see just how many posts folk can do before someone answers the OP question properly.
Either that or this has to be the hardest question in the world of diving to ask.

“How much drive air does it take to run a Haskel Mini Sport” over the full range of supply oxygen pressures.

Would have thought we would have the answer by now, after all the companies selling them have been doing it for years.
That, or its so darn much no one dare give you a straight answer for fear knowing at $2 a tank for drive air it costs more than the $7.00 oxygen fill.

Who would have thought a drive air chart would be such hard work to get hold of.
Hope we get there by around post 30 which is just about the same CFM rate you need to drive the thing full range in the first place.

 

[Wookie]

It’s going to be interesting to see just how many posts folk can do before someone answers the OP question properly.
Either that or this has to be the hardest question in the world of diving to ask.

“How much drive air does it take to run a Haskel Mini Sport” over the full range of supply oxygen pressures.

Would have thought we would have the answer by now, after all the companies selling them have been doing it for years.
That, or its so darn much no one dare give you a straight answer for fear knowing at $2 a tank for drive air it costs more than the $7.00 oxygen fill.

Who would have thought a drive air chart would be such hard work to get hold of.
Hope we get there by around post 30 which is just about the same CFM rate you need to drive the thing full range in the first place.

Well, could you have posted the drive air chart, or did you just swing by to tell us all how inadequate we all are?

 

[OceanEyes]

could you have posted the drive air chart

That would be nice.