For Sale Mini booster

[moose_grunt]

Selling my GAF mini booster. It's been great for the last year and a half or so when I bought it new, but the $1600 bill for a 200ft3 of helium has convinced me to upgrade to an electric booster to scavenge the tanks waaaaay down.

This is air-driven from a BC hose, and has 1/4 NPTM for the supply and outlet gas. I have an extra set of piston seals and a user/maintenance manual.

$750 (net to me, so send as gift, pay the fee, etc.) and I'll cover shipping to the US. I will ship worldwide, so contact me and we can work out the costs.

Jim

 

[tmassey]

How low can you realistically get from the supply? And what type of cfm do you get at, say, 500PSI inlet to 500PSI outlet?

My understanding is that these are best for filling 3l type bottles and I’m looking for scavenging He into doubles. I realistically need to move 100 cf of He and reach 1300 PSI to make 21/35 in a set of 120 or 130 doubles. Is this practical?

 

[Wookie]

I scavenge with either my Masterline Electric or my Hydraulics international Mini down to about 500 PSI, and I can't get much lower than 400 PSI without tearing up the seals. What's important is not inlet pressure, but ratio. Neither my electric not the air driven is much good above 10:1. 1:10.

YMMV

 

[tmassey]

10 to 1 ratio where? Supply pressure to outlet pressure? Supply pressure to drive pressure?

For me, a booster would serve two purposes: one, being able to refill tri-mix without dumping the existing gas. Let’s say there’s 1500 psi of remaining mix. That means I need a booster to put 900 PSI in the tank (2400 PSI max pressure). Two, being able to get as much out of the supply tank as possible. Ideally, say 200 or 300 PSI.

But I don’t have to do both at the same time. I would be OK in scavenging into empty doubles when the supply was below 1000 PSI, and boosting when above.

By my reckoning, that means I’d be at less than 5:1 (assuming outlet:supply) in either case. But you said you could only get down to 500 PSI? That’s literally 1/4 of the supply volume...

 

[tmassey]

A quick Google did not find a specific model. Any details on the specific model? I’m trying to find the cylinder volume and capability graphs.

I have looked at Haskel pumps in small detail. I know the haskel mini sport booster is not practical, and I’m guessing this one won’t be either. But I’d really like a booster so I’m trying to really make sure I can’t make it work!

 

[tbone1004]

A quick Google did not find a specific model. Any details on the specific model? I’m trying to find the cylinder volume and capability graphs.

I have looked at Haskel pumps in small detail. I know the haskel mini sport booster is not practical, and I’m guessing this one won’t be either. But I’d really like a booster so I’m trying to really make sure I can’t make it work!

why wouldn't the baby booster be ideal? it will work for what you're doing, it's just slow. My understanding is this is similar to the KISS/Jetsam baby booster, just a lot better.

In terms of ratio, there are things boosters can do, and things they should do. I.e. the AG30 that I just bought "can" take 300psi gas and turn it into 2700psi gas, but it takes a million thousand cf of drive gas to do it and it goes 0.5cfm or less.
If however you took the 300 and boosted it to 1500psi, then it will go about 3cfm using, then you take the 1500 and make 2700 and it is significantly happier doing that since it is a lot less stress on the components. All of the boosters work like that though so if you can do intermediate boosting, especially if doing big bottles, they'll appreciate it.
If you are regularly trying to scavenge low pressures out of something, you need a compressor not a booster. I'm aware of two. The ideal one is the Rix Microboost, the other being the compressor inside the Invacare Homefill units. Both of which are 3 stage compressors that use a ~20psi inlet *essentially the first stage of 4 stage compressing*, but neither of which enjoy going much over 2200psi since they were designed for oxygen

 

[Wookie]

10 to 1 ratio where? Supply pressure to outlet pressure? Supply pressure to drive pressure?

For me, a booster would serve two purposes: one, being able to refill tri-mix without dumping the existing gas. Let’s say there’s 1500 psi of remaining mix. That means I need a booster to put 900 PSI in the tank (2400 PSI max pressure). Two, being able to get as much out of the supply tank as possible. Ideally, say 200 or 300 PSI.

But I don’t have to do both at the same time. I would be OK in scavenging into empty doubles when the supply was below 1000 PSI, and boosting when above.

By my reckoning, that means I’d be at less than 5:1 (assuming outlet:supply) in either case. But you said you could only get down to 500 PSI? That’s literally 1/4 of the supply volume...

I boost to 4500 PSI...

 

[tmassey]

I'm looking to get He into doubles, not particularly transfilling bank bottles. 2000PSI gets me to 15/55 on empty HP's, and that gets me to 240'. It'll be a while before I need to exceed that... Given 10:1, I could get that down to 200PSI supply (theoretically). For 21/35, that same 200PSI supply is only 6:1 ratio.

Intermediate boosting is not something I had thought about. I can see needing that to get past the 10:1 limit. I will have to do some playing with math and see how it will change things in the pressure/volume regime I'm interested in (100CF @ 1000PSI - 2500PSI). I can see wasting an entire supply bottle priming the process... but then being able to get future supply bottles quite low -- at the cost of pumping gas two or three times... with a slow booster... Good/Fast/Cheap: Pick two...

I'm sorry for half-hijacking this thread. I really *do* want to buy a booster... if it will work for me. I am still very interested in the exact model so that I can get some exact specifications!

@moose_grunt : how did you use it?

 

[moose_grunt]

I'm looking to get He into doubles, not particularly transfilling bank bottles. 2000PSI gets me to 15/55 on empty HP's, and that gets me to 240'. It'll be a while before I need to exceed that... Given 10:1, I could get that down to 200PSI supply (theoretically). For 21/35, that same 200PSI supply is only 6:1 ratio.

Intermediate boosting is not something I had thought about. I can see needing that to get past the 10:1 limit. I will have to do some playing with math and see how it will change things in the pressure/volume regime I'm interested in (100CF @ 1000PSI - 2500PSI). I can see wasting an entire supply bottle priming the process... but then being able to get future supply bottles quite low -- at the cost of pumping gas two or three times... with a slow booster... Good/Fast/Cheap: Pick two...

I'm sorry for half-hijacking this thread. I really *do* want to buy a booster... if it will work for me. I am still very interested in the exact model so that I can get some exact specifications!

@moose_grunt : how did you use it?

This is a clone of the Kiss baby booster with Swagelok non-return valves instead of the reed plate, and a German Hafner spool valve to control cycling. Supposed to be same specs as the baby booster, and will supposedly boost to 240 bar. I'm not that brave, and stop around 180 bar (2400psi) since I'm only filling LP 2L (13ft) tanks.

I used it to boost o2 into rebreather tanks after trans filling. It is painful to babysit a mini booster trying to move a lot of gas at high pressure. It takes a lot of time, a lot of drive gas, and needs a lot of breaks because the booster gets hot just whacking away at it. When I need to fill bailout and deco gas it's usually my cue to get new supply tanks to start from.

Honestly, if you're just interested in trimix fills into doubles, I'd look at picking up one of the many cheap used compressors floating around on SB, building a nitrox/trimix stick, and using that. Just my .02, and not a great job of trying to sell my stuff, but oh well.

Jim

 

[moose_grunt]

Sold