Compressor for running my Booster

4ster

I looked at some oil-less compressors today and I think I need a reality check.

So I inspect one at the store that I think that should drive a Jetsam Baby Booster (http://www.dewalt.com/us/products/to...roductID=15538) and read the manual. One of the product warnings says: "The compressed air directly from your compressor is not safe for breathing. The air stream may contain carbon monoxide, toxic vapors or solid particles from the air tank. Breathing these contaminants can cause serious injury or death." It says that a filter should be installed that is capable of treating air for human consumption.

Another section of the manual states: "Air tools and accessories that are run off the compressor must be compatible with petroleum-based products. If you suspect that a material is not compatible with petroleum products, an air line filter for removal of moisture and oil vapor in compressed air is required.

So I am thinking there are at least 3 possible explanations: 1) DeWalt hires product liabity attorneys that are well paid to come up with this stuff, 2) the guys who write the manuals are not well paid and just paste boiler plate from old manuals into the new manuals or 3) an oil-less compressor used to drive nail guns is not as clean as one designed to supply breathing air.

Now I know I am not breathing the drive gas, but depending on the booster design contamination could be an issue. I looked in the Jetsam manual today and could not find the quote but I seem to remember Jetsam recommends the drive gas for their booster to be "breathing quality" air. Being that the consequences of contaminating the booster could be ugly, I think I will call Jetsam and get their advice. I'll post what they say here.

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Steve
"My problem is that I have trouble reconciling my gross habits with my net income." Errol Flynn

bletso

I have a Haskel AG30. It is amazing how much drive gas they can take. At the office I have a 25hp compressor and it can cycle it frequently.

But at the house, I have a small 4hp with a 21 gal tank. It is noisy, not real fast, but adequate. My wife hates it.

The trick is that with a small unit you will need a continuous duty compressor because the cycle pressures on most units will stall the booster. i.e. The compressor shuts off at say 130psi, the booster goes on but then stalls when the tank pressure drops to say 100psi, but the compressor won't start untill 90 ps1 is reached.

You may need a good controller to get a narrower window than what most small compessors come with. I just run the haskell full out and the compressor just ever so slowly keeps slightly ahead. I occasionally bleed a little of to keep it from shutting off. (The cfm is low enough that it cylces maybe 10 strokes a minute.


Dale

SteveL

So knowbody took the bait Dude. Were you showing off your pumper or your receiver(s)

Steve

heyydude

Hey Steve,

Neither.

If I were to start showing off, even you would be impressed...



---> But I AM very exited about my new compressor. Ted Green gave me a great lecture about Motors yesterday, and I'm looking forward to speaking to others who can help me learn more about this behemoth. Did I mention that it has TWIN 6700 psi Working Pressure storage tanks!?!

See, not "knowing it all" is the best part about this business. Always something new to learn about.

Of course, the wife doesn't see it that way. She didn't even want to come out to the shop and look at it.

Women.

I just hope it doesn't blow me up - I'd have some REAL explaining to do...

Later,

Kevin.

trob09

Duuude!

4ster

I spoke with Simon at Jetsam yesterday. He tests the boosters there. I thought it was entertaining that he had "nerver heard" of powering a booster from a shop compressor. He said that in their testing before they send a booster out the door that they use bottled gas to drive the boosters even though they have an extensive shop compressor system.

We talked quite a bit about air quality and how it could affect the booster. After that conversation I think I will run the compressor output through a good water seperator and filter before it feeds the booster.

Steve

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Steve
"My problem is that I have trouble reconciling my gross habits with my net income." Errol Flynn

Tom Rose

Yes...you are correct..the booster is designed to be run on a first stage....it is clearly a small booster for the individual diver...particularly one who travels...However, Gordon and I talked about using shop air some and I started doing it, it has worked fine for me.

The water separation and the air filter won't hurt. My booster however is #008 I think and is still running just fine. A couple of years ago Kim emailed me asking if I had had any problems....nope I answered...If I remember right the problems were due to oil contamination...don't quote me. There is some corrosion on the external brass parts of my booster from salt air but it runs perfectly....at least it did last night as I pumped up for some testing this weekend.

I actually prefer to use the booster on my home compressor because I do not fully trust the air in Scuba tanks from the standpoint of oil and other ingredients....I am also down to only small air tanks now and do not own any tanks above 30 cubic feet.... down from about 10 of those big heavy buggers.

Tom

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The 50-50-90 rule: Anytime I have a 50-50 chance of getting something right, there's a 90% probability I'll get it wrong the first time.

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brewmaster

the plumbing is easy, you can get every thing at a good hardware or auto part store. in the US the auto stores make up brake and hydraulic hoses, the only thing is watch them make up the hose. donot let them us lubicant on it unless it is o2 compatable. the problem is the cfm needed to drive the pump not the psi. my haskel need 12 cfm to run it well most home compressors ar 4 to 5 cfm. i had to get a two stage compressor to make it work with out stalling.

4ster

Thanks Stuart, this thread got me thinking about using a small, portable compressor to power my booster. Based on other's experience (especially Tom's) I was able find one that performs well for me. (DEWALT D55146 : 200 PSI 4.5 Gallon Electric Wheeled Portable Compressor) I used it to do a couple of Nitrox fills today and I am really pleased how things worked out.

The key was recognizing that you really want the pressure of the drive gas to be at the booster's optimum pressure all the time. Looking at what was available for portable, oil-less compressors I found that there has been an evolution in some models toward higher operating pressure. The DeWalt runs up to 200psi cut out pressure. More importantly the cut in pressure is 165psi. Since my Jetsam booster is designed to run at 147psi (10 bar), that means that the pressure at the regulator can be set so that this is supplied all the time, with no cycling below the optimum drive pressure.

The compressor's flow is rated at 5.3 cfm at 90 psi. It turns out that matched to the Jetsam booster this works out to a 50% duty cycle , well within the compressor manufacturer's recommendations. I added a small oil/water seperator for my own peace of mind, it is reassuring to look at the glass bowl and see no water in its trap. A small 1/4 inch ball valve was added to the seperator to control the drive gas.

Now I can fill my little rebreather cylinders to my hearts content, not having to worry if there is enough drive gas around to do the job. Thanks all!

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Steve
"My problem is that I have trouble reconciling my gross habits with my net income." Errol Flynn

colinicky

Link does not seem to work ?

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Colin

I trust my rebreather completely ,
I just don't trust the user

onwards & downwards