USUN boosters

[aquaregia]

I'm trying to figure out which USUN booster I need to pair with my compressor, I'll drive it off my air bank. I've got it narrowed down to the XB30, the XBD30 and the GBT15/40, and I'm sure the 15/40 will do everything I can dream but I've had people suggest that it might be overkill. What I'm trying to do:
1. Filling 3L rebreather oxygen bottles, I'm sure any of the boosters would be fine for this.
2. Topping up OC deco bottles of 100% and 50%. I'm unsure if the XB30 has enough flow to work with AL80s, all the notes talk about it working great with 7L and smaller.
3. Scavenging trimix from my OC doubles. I know the GBT15/40 can take them down to 100psi rather than 500psi, but I'm not sure if I'm going to actually care.

Does anyone have experiences here?

 

[davehicks]

I recently got an XB30 and it's working well. I did need a bigger shop compressor (5.4 cfm) than my old Maximator booster. I fill CCR O2 bottles and 40cf stage bottles. Yesterday I was filling O2 and the source bottle got down to 300psi before I pulled the plug as it was getting too slow. So, you can scavenge a lot of gas if you don't might giving it time. An 80cf at 3000psi would be no problem you would just need enough source gas and some time.

 

[InWay2Deep]

I bought a XB30 to refill my re breather o2 bottles, it works great for that OTHER THAN the fact I can only pull my O2 K bottle down to 500ish PSI before I have to trade it in for another one. Not a huge deal, O2 is cheap.

My issues with it comes w/ your second use case, scavenging. Are you really doing much scavenging if you can only pull your supply bottles down to 500psi? When my T bottle of H2 runs almost $500 for a refill, I want every last drop of that. Thankfully I also have a small compressor so I just built an OmniBooster and I run it though my compressor to get the last bit of mix/he out of my tanks.

Get the 15/40, just watch your supply pressure, you will have to regulate it down, this will give you the most options.

 

[aquaregia]

Most of my scavenging is when my OC doubles need to go in for vis -- I lose about 100 cubic feet of 18/45. 500psi would leave ~35cf in there still, which is better than 100cf but not the 10cf that I guess I could get down to with the 15/40.

 

[aquaregia]

Just looked up Omnibooster: OmniBooster. This works well?

 

[InWay2Deep]

Just looked up Omnibooster: OmniBooster. This works well?

Working for me. I built it a few weeks ago using a old reg set I have a bunch of spare parts for that I don't plan to ever taking diving again. It, plus about $20 in plastic from the HW store and I am able to move some TriMix from one tank to another and get the last drop of He out of my T bottle. Some people prefer the plastic bag thing, but the way I set it up on my little compressor all I have to do is throw a lever and switch between the 2 intakes (fresh air and omnibooster) and I don't have to monitor flow just pressure of the supply tank.

 

[trimmatters]

Ok, here's the notes I put together to help structure my thoughts when looking for the right sized booster.

These thoughts were aimed at acquiring a booster almost exclusively for filling butt-bottles with O2, and maybe (super infrequently) topping off the occasional S40/S80, so ymmv.

The use-case for the trips I put this together for have serious weight and size considerations so keep that in mind if that's not your thing.

Really just wanted to get this down for future reference and chatting with my dive team. Please feel free to pick it apart or ignore, I claim zero expertise.

boosters can ....

1. move gas fast
2. suck more the gas out of the source cylinder (scavenge)
3. or use not much drive gas [needs validation?] and be slower, smaller in size, and less weight

these map to ...

1. double action - both sides of the piston driving so gas moves fast in to target. Great for filling larger cylinders (S80 etc)
2. two-stage - allows very low pressure from the source to be pushed into the target cylinder. Great for expensive source gas.
3. single action, single stage - yeah, slow and doesn't scavenge as much, but much much smaller, cheaper and lighter.

From the outset, [for our use-case] just forget two-stage. Love the idea, but the weight and size in the u-sun range is prohibitive. Absolutely can be done for those who have the coin, but yeah nah.

Even just for the right sized single-stage you can see a 60% increase in weight (screen grab)

Find my thoughts on driving the XB-30OL I purchased here: USUN XB30 Drive with "Shop" air?

 

[TravisD]

I'm still figuring this stuff out myself, but don't two-stage boosters also gain an advantage in keeping the compression ratios down to a safer ratio for O2?

 

[broncobowsher]

I just run the booster slower. Haskel rates the boosters for 50 cycles a minute (almost one per second). I'm pumping O2 (and helium, and air) at 30 cycles per minute. Just compress at a slower rate. Also trying to keep the fill rate slow enough in the process.

 

[rjack321]

Just looked up Omnibooster: OmniBooster. This works well?

A trash bag is vastly cheaper. But obviously neither work for O2