Best Booster for Rebreathers

[marc.collin]

use air tank to drive gas reduce complexity and hardware to buy

hard choice

xb30-ol	6.8kg	1666$ cad
xbd30-ol	11kg	1916$ cad
sb40-ol	11.5kg	1777$ cad

 

[broncobowsher]

I would pass on a double acting booster for CCR bottles. They are meant to move large volumes of gas at more modest pressures - like OC doubles...

Either the 1:30 or 1:40 is fine. Don't worry about ridiculous 300bar outlet pressures, they are completely unnecessary and a giant waste of drive gas. Assuming you even have and need a CCR bottle rated for 300 bar.

Plan on buying a shop compressor and air drier to drive it.

Another benefit of a shop compressor for drive gas. When the supply bottle is getting low and the booster gets inefficient. It doesn't matter. The O2 bottle getting down to the last few hundred PSI and you almost have the CCR cylinder full, each cycle only does a few PSI boost. You will blow through a ton of drive gas, which if you are getting fills at the local dive shop to run the booster will be a lot of fills from the local dive shop. Or the shop compressor will just run and move that gas.

People often don't have issues sending O2 back with a few hundred PSI in it. Cheap enough. But Helium, you want ever molecule you can get out of that bottle.

And 300 bar is useless. I am sure there are a few super special situations where it is the right choice. But those are so rare that by the time that you get to them you will have had several different rebreathers, boosters, and breathing air compressors in your ownership and won't be asking the questions of if it is what you need.

 

[rjack321]

use air tank to drive gas reduce complexity and hardware to buy

hard choice

xb30-ol	6.8kg	1666$ cad
xbd30-ol	11kg	1916$ cad
sb40-ol	11.5kg	1777$ cad

You are radially increasing your costs using scuba compressor drive gas and going to wear out your little scuba compressor much faster.

Trust us, you will end up a shop compressor anyway. 5cfm bare minimum, 8 cfm is better.

 

[greeniguana]

You are radially increasing your costs using scuba compressor drive gas and going to wear out your little scuba compressor much faster.

Trust us, you will end up a shop compressor anyway. 5cfm bare minimum, 8 cfm is better.

Unless you spend money on a real shop air dryer, or have fabrication skills, or live in Arizona, you're going to ruin your booster quicker with wet shop air. Those little Chinese water separators don't really do anything.

I fill a pair of 104s every couple months and they are more than adequate to fill/top off 13s and 40s. I have a CH 2 stage 20gal shop compressor that does 6.5cf @ 90 psi. It doesnt even close to keeping up. Maybe it would be OK if you had a 60-80 gal tank. If I use my shop compressor to boost a 40 or 80 I will need to empty the 5lbs of dessicant in my dryer and dry it out.

 

[broncobowsher]

One of the things you can do with a shop compressor is get a higher pressure rating, nice 2-stage for example. Running a higher pressure in the 60 gallon tank will squeeze more water out. Then when you regulate that air down to a lower pressure it will be drier.

I've done parking lot boosting before. Rough calculation is a 100cuft scuba cylinder boosted a rebreather cylinder. All depends on what you start with and what you try to end with. Your results will vary. But that is my ballpark estimate for air needed to boost.

 

[marc.collin]

for the couple of fill i will do for trimix, oxygen... don't think i will waste several tens of thousands on a dive shop compressor...
prefer to get another rebreater or a tank scooter

 

[Gone for diving]

don't think i will waste several tens of thousands on a dive shop compressor...

(several tens of thousands)????

I am sure its possible to spend 20000$ on a HP dive compressor...
but I think your doing it wrong.
Buy used.


But for 1500$ ish you can get a nice 2 stage 150 psi 5 hp shop compressor to run a booster.

Running a booster on tanks at dive site is a solution, which makes alot of sense.

In your garage a shop 120-150 psi compressor makes more sense.

Seems people are confused between a shop compressor. And a dive shop compressor.
One runs 120-150 psi and the other one runs up to 4000 psi.
One is quite abit cheaper and cheaper to run.

 

[marc.collin]

(several tens of thousands)????

I am sure its possible to spend 20000$ on a HP dive compressor...
but I think your doing it wrong.
Buy used.


But for 1500$ ish you can get a nice 2 stage 150 psi 5 hp shop compressor to run a booster.

Running a booster on tanks at dive site is a solution, which makes alot of sense.

In your garage a shop 120-150 psi compressor makes more sense.

Seems people are confused between a shop compressor. And a dive shop compressor.
One runs 120-150 psi and the other one runs up to 4000 psi.
One is quite abit cheaper and cheaper to run.

my error... i read to fast
will check... more important is to choose a booster pump

 

[rjack321]

Unless you spend money on a real shop air dryer, or have fabrication skills, or live in Arizona, you're going to ruin your booster quicker with wet shop air. Those little Chinese water separators don't really do anything.

I fill a pair of 104s every couple months and they are more than adequate to fill/top off 13s and 40s. I have a CH 2 stage 20gal shop compressor that does 6.5cf @ 90 psi. It doesnt even close to keeping up. Maybe it would be OK if you had a 60-80 gal tank. If I use my shop compressor to boost a 40 or 80 I will need to empty the 5lbs of dessicant in my dryer and dry it out.

The 13x in your scuba compressor filter is vastly more expensive than your reusable shop air desiccant.

If you add some copper coils and storage you can get more water to drop out of your shop gas before it gets to the dessicant

 

[greeniguana]

The 13x in your scuba compressor filter is vastly more expensive than your reusable shop air desiccant.

If you add some copper coils and storage you can get more water to drop out of your shop gas before it gets to the dessicant

I'm not here to argue with you. I had all that stuff, and it works. You still need a massive shop compressor..... I've now decided the convenience of using tank air is worth it. When i was younger and had the time to build stuff - sure. I figure anyone who owns their own home fill station does not have filter frugality high on their list. I change my bauer filter 2-3x a year, which is less than $150.

Since this thread was fresh in my mind, I took notes on drive gas consumption yesterday. I filled 2x 13cf tanks with O2 from an Al80. I drove the booster with 2x PST 104s (3000psi each). The 80 had 2000psi of O2. One 13 was completely empty, the other had 1500psi. I filled the empty 13 to 3000psi using 2000psi from one 104 and filled the 1500psi 13 using 1000psi from the other 104. I then filled up both 104s afterwards, so I can repeat the process next month or whenever.