Questions about mini boosters

womble

Please pardon my ignorance, I don't know a lot about these. . . . .

I'm looking at getting a mini booster to keep my O2 / dil cylinders (3l and 5l) topped up.

E.g., if I have 2 dil cylinders which are both at 90 bar, I'd like to be able to boost one from the other to give me enough mix to do a couple of dives. The alternative is to dump 90 bar of mix and get a new fill from my LDS . Not a big cost implication with only 3l of mix, but from a convenience point of view it woud be great to be able to do this.

My questions are:

1) on the specs of the various boosters it lists the ratio - e.g for the mini Haskell it says ratio 25-1. What does this ratio mean??

2) How much drive gas is used?? Say in the above example? So how long would a 15l steel 232 bar full of air last? How many 3l cylinders would I be able to boost to 230 bar of mix/O2 on this 15l of drive air?

3) does the drive air also have to be O2 clean?

4) Can a mini booster be used to pump enough O2 into a ALI 80 for a mix of EAN50??

5) can any of the mini boosters be driven by hand, or is it not worth it??

Thats all I can think of at the moment . . . I'm sure I will have more questions, thanks in advance for your answers.

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jradomski

The ratio is drive gas pressure to product gas pressure.. that means at 100psi drive gas the maximum output can be 2500psi, 150psi=3750.. in reality due to friction the maximum pressures are usually a bit less..

the higher the ratio the higher you can boost from lower drive pressures but it comes at a cost of more drive gas.. a booster having a ratio of 20:1 will boost more efficiently but will require higher drive gas pressures..

All single stage boosters become very ineficient when the source pressure becomes low.. usually around 1000psi is about the limit if you want to boost to 3000 psi.. if 2400 psi will do probably around 750 psi is about as low as is reasonable.. You can go lower but you need more and more drive gas unless you will accept lower final pressures.. Unless my source gas pressure is really high I usually boost my tanks to around 2400-2600 psi.. The amount of extra dive gas thats usually needed for that few hundred psi is not worth it.. Your drive gas goes furtehr doing multiple top offs than trying for max pressure on 1 fill..

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Joe Radomski
CCR Trimix Instructor Trainer
ANDI Instructor Trainer Director #10

All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated.

womble

thanks Joe, I think I understand that bit now .
anyone any other helpful hints??

Thanks in advance

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"What could possibly go wrong?? . . "

jradomski

depends on the booster and source pressuressures.. a single al 80 is usually enough for me to boost for a week of top offs as long as I dontr try and boost beyond reason..

for a properly designed OXYGEN booster no.. but some of the common ones (like jetsam) do really need clean gas if you plan on boosting oxygen to eliminate contamination risks..

making 50% on al al80 takes about 32 cuft of o2, if you start with a reasonable source pressure and an empty al80, yes..


yes some have hand options.. options usually limit final pressure to around 2000 psi

__________________
Joe Radomski
CCR Trimix Instructor Trainer
ANDI Instructor Trainer Director #10

All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated.

womble

Joe, thanks again

__________________
"What could possibly go wrong?? . . "