Very Small Compressor?

[Eris Lucan7*]

There are the old giantbig 1 ventilpressurecompressors they run over 1 big weel

to the outlet mostly providet over a car or trukmotor,they are big and the best

15 and more tanks in 1 hour...E.L.7

 

[fishoutawater]

I don't really know anymore. Maybe the technology has changed since I was certified in '74. I distinctly remember the guy saying scuba tanks required the use of a "water lubricated compressor", and that oil lubed pumps would get hot and put burned hydrocarbons in the air.
So, now I take it that there are filters that will remove burned hydrocarbons?

 

[Eris Lucan7*]

That old compressor are oilfree They have fat... and the water never reach the

bottel,a filter is best placed as molsty bevor the fieltubes...

E.L.7*

 

[ronski101]

I still have a cornelius that I had bought in the 70's for scuba. It has 3 stages and takes about 1-1.5 hrs to fill an 80 to 3-4000psi. It still works as I used it to fill some tanks for a Baja trip last year. It is Gimler belt driven by a 110v electric motor. It has double filtration and a water trap. It is housed in an aircraft type housing with numerous gauges and takeoff points. Who ever built it knew what they were doing. The only thing I don't like about it is it is pretty noisy. It uses casteroil for lubrication.
I would really carefully investigate what it takes to make a safe scuba compressor before building one or risk being talked about in the accidents forum.

 

[pp-1-3-5-7-9]

Regarding the "water lubricated compressor" Base my understand is meaning by water cooling but not using the water for lubricating, basically, during the air been compressed in each time it will generate a lot of heat, therefore the compressor cylinders design be have either built with fins and cooling by air or a water jacket (like car engine) and cooling by water to cool down the compressed air temperature to avoid an over temperature happened and damaged the compressor.

Usually, the operating temperature of the water cooling type compressors is lower than the air cooling type one and will resulted with more higher efficiency also can be reducing the lubricant oil fumes generated and better for breathing purpose. because of the structure of the water jacket is more complex than the fins, for this reason we only can be found it in large scale compressors.

 

[Lymington Biker]

I had a thought, is there a small compressor that could deliver very high pressure (5000psi) at a very low cfm rate that could be adapted for SCUBA use? My thought involves building a home filling station that would take a few hours to fill tanks running a small compressor. Think trickle charger for SCUBA tanks.

I already have a large shop (non-SCUBA) air compressor that gets the neighbors excited if I forget and leave it on overnight!

I would be realy interested to know if you found a solution to this problem. As I am in a similar situation. Only I need to re pressurise a normal dive sized cylinder containing ARGON gas to its standard fill pressure. Unfortunately Dive/paint ball compressors are well beyond my price range. Also why do I need to be able to fill it in 30 minuets when I only need to re fill the cylinder once a month ?. So I would be very gratefull if you haveany info on a small compressor that was cost effective and did the job over several hours.

Email me: Rgale77364@aol.com

Thanks
Rob

 

[sunnyboy]

Two things.

1. You are going to have to pay some amount of money for any compressor capable of delivering diver grade breathable air. Even adapting something will require a filter stack and stainless hardware, and this stuff isn't all that cheap. So you have the min-max problem of shaving cost but not compromizing safety. Somewhere the two curves cross.

2. What about something like the Alkin W-31 compressor? 3.5 cfm, 4500 psi, Under $4000 complete, ready to go. These things are low rpm and very quiet (mine is set up INSIDE my house). I also have a Dewalt oil-less compressor to drive my booster, and it is WAY louder than the Alkin.

Again, to get a compressor that will reliably deliver diver-grade air, you are going to have to spend money. Something like the Alkin is quite inexpensive (for what you get, complete) and will deliver.

Cheers,

-S

 

[pescador775]

Yes, there were water lubricated compressors in the 1950's. That was before principles of filtration were well understood by the diving community. Same for the RIX machines which have been the subject of much misunderstanding regarding filtration. Neither are necessary for SCUBA jamming.

The once popular three stage Stewart Warner 4 cfm and 3.5 cfm which were sold to divers, and are available at govliquidation.com right now, had only a condensator with no final filter. However, the recommended lubricant was medicinal grade mineral oil. Todays's oils are non toxic but should not be allowed to enter a SCUBA cylinder for several reasons, but particularly for PP filling of NITROX tanks. The SW's and the well known Walter Kidde 4 stage pumps are often converted for divers and paintballers. Assemblies for divers are similar to the rest but fitted with a condensator and a chemical filter containing activated charcoal and desiccant of some kind (like 13X).

I can't help with comments or complaints about noise except to point out that the small Cornelius is pretty noisy as are most high rpm pumps, even the Kidde. It is not likely that one could solve everybody's problems, eg, find a source of no noise, high pressure compressors at zero cost. However, there is a little "club" on Yahoo which discusses the small, military surplus compressors in theory and the mechanics of conversions. Suggest some of these issues be aired there.

kidde-compressor-folks : Military Surplus HPA Compressor Folks

 

[Jimmer]

BAUER COMPRESSORS - Products - Shooting - Rifleman Compressor S30

This is meant for air rifles and handguns, I know some people are using it for paintball markers. It can pump to 4500psi so I guess with the right filtration you could fill a scuba tank with this.

 

[sunnyboy]

Just another comment on the noise. For compressors, noise is often a function of RPM. My Alkin W31 is low-rpm and therefore very quiet. It can put out up to 4500 psi, and takes about 30 minutes to fill an AL-80 from empty.

As a comparison, I bought a Dewalt 150 PSI "oil-less" compressor (typical job-site air nailer compressor) to run my Jetsam baby booster. That thing is about 10x noisier than the Alkin.

-S