Using Hog 1st stage to drive booster pump

[RayfromTX]

I'd like to use a Hog first stage to supply drive air for my HI 5G-TS-14/30 booster pump. I realize I will pay the penalty for hours on my Rix SA-6 and my LF filter cartridge but I avoid a BIG upfront cost in LP compressor and dryers. This is personal use so the LF filter cartridge will likely be replaced on months elapsed and not hours used.

I can order a DIN female adapter from add helium to tie the regulator into my bank system but I think I can save by threading a fitting directly into the Hog. What is the thread I need to do this? Is this just a really dumb idea?

 

[Tug]

@macado does something similar to what you're envisioning and while it's not the most efficient it's worked for us to boost using a shops bank tanks for drive gas

 

[tbone1004]

if you have a bank system, why don't you just use a welding regulator?

 

[RayfromTX]

Hog 1st on sale for 100$

 

[tbone1004]

$100+$50 for the din adapter, vs this

https://www.amazon.com/Uniweld-RHP4...1487527568&sr=8-17&keywords=welding+regulator

nitrogen regulator with easily adjustable pressures for $60.... remove the CGA580 connector and the NPT male out from your bank system will screw right in. less than half the total cost

also, I assume you're doing this for pure O2, not PP blending nitrox?

 

[RayfromTX]

Tbone, That regulator does not appear to be rated at the up to 4,500 psi of my bank system. I plan to use the booster for PP nitrox and trimix blending although I still have to learn a lot before I actually attempt that. I need to study up including a couple of times through the oxyhacker's companion and I have a lot of training ahead of me before I'm ready to actually dive with trimix. At this point I have training in using nitrox only. I don't actually have the oxygen or helium tanks but I'm getting it set up for summer.

 

[grf88]

Why not just continuous blend for your nitrox and trimix.

 

[tbone1004]

@RayfromTX if you have the oxyhacker, build a blend stick instead of pp blending, no reason to PP mix if you can continuous mix. PP blending is very inefficient, especially if you are driving from your scuba compressor, and requires the extra expense and hassle of o2 cleaning. You can blend nitrox and trimix through the rix with no issues though when you get into pretty high He mixes you'll want to PP the first bit since the compressor tends to get a bit toasty with that much helium in the mix. You won't have to worry about that for a while though and when you PP blend, you're not going to need the booster for all that much. The biggest use will be for O2 tanks, and for that I'd really look on craigslist for an oiled continuous duty compressor. Rix parts are wildly expensive and the $400 or so you'll spend on a continuous duty compressor on craigslist will pay for itself pretty quickly after keeping the hours down on the rix.

The rix will have 0 issues pumping ean32/36, and up to probably 21/35 trimix which means you'll only be using the booster for deco fills. The rix will also be able to suck the o2 and he bottles dry and the booster won't.
Electric Air Compressor
Speedaire air compressor
* Campbell Hausfeld - Extreme Duty * - 60 Gallon Air Compressor

Your booster is also going to consume quite a bit more air than the Rix can deliver, expect at least 2x, and up to 4x, so getting an adequately sized compressor will allow you to actually fill without draining the banks and having to wait for it to catch up. I promise you though, you're going to spend more on Rix maintenance than you'll save by going with this solution now though

regarding the pressure, the regulator is probably fine, it's just the gauge that won't like it. There are other higher pressure regulators out there that are under or around the price of a D1+the female din adapter and will be less annoying to deal with since you'll also have a pretty big pressure drop through the small hose and extra cost to go to NPT from the regulator hose. You won't find an adapter to accept NPT in or anothre CGA fitting in, so best off to have it machined down if that's the route you want to go, but it's not the way I'd go

 

[RayfromTX]

Hi Tbone
I'm more concerned about the Rix pumping He than I am about it pumping for more hours. Iain warns many times about running them hot and what that does to the life of the rings. I've got it indoors to keep it cool and clean. My problem with a big compressor is I would have to put it in the shop and run a long hose, which I could do but I'm not going to get one big enough for anything like the ones you found on Cragslist. Thanks for doing the search by the way. You to a lot for the people on this board.

The compressors you found all put out less cfm than the Rix. The Campbell Hausfeld came close when it was new but it is a 3hp 6.5cfm that isn't rated for continuous duty. The speedaire looks just like the one I just threw on the trash pile. I bought it in 1984 and ran my crew off of it for many years. It still runs but it's junk.

For 300$ you can buy a new Makita that puts out the same 5.2 cfm but all of them are rated for a 50% duty cycle. The booster wants 20 cfm but will run ok on 10 and even less but you have to throttle the output of the air drive on the booster to keep the psi above 100 and then the pumping speed is going to be really slow and the duty rating of the little compressors is going to wear them out. I could buy 2 or 3 and run them parallel but it really doesn't get me past the duty cycle rating. The solution may be to buy a real 2 stage 18cfm compressor and if I still used air for work I wouldn't hesitate or if planned to drive the heck out of this setup like if I lived in Florida or someplace where diving was a several days a week thing but alas, I live in central Texas and I'm just trying get my fix in between trips to blue water where I'll be diving somebody else's air anyway.

Maybe I should have put the old speedaire on CL.

 

[RayfromTX]

The campbell Hausfeld is a 10.2 at 90psi so it might do it at half speed but not sure how it would like running full out for a couple of hours. This one might stand a better chance. Campbell Hausfeld TQ3104 5 HP 80 Gallon Oil-Lube Shop Air Stationary Vertical Air Compressor Not sure why the seller is trying to get 450 for an old compressor that sells new for under 600 and he claims it is so he can get a craftsman to match his tools. sounds fishy.