air driven Vs manual booster

jmurba

Ha yes,

our friend Tom is sometime difficult to understand for me... I am French...
I had not understand this clearly, i tought he was only deploring not to be able to increase a little bit the pressure without braking the guarantee.
I think that a skilled mechanic or technician could easily turn a screwn and increase the pressure in a reasonnable rage, say 25 bars more or so....

regards

jean mi

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bletso

Jean Mi,

I do the same and like you sometimes I wonder. Then I remember what a wise and knowledgable sage once said, "No one ever died havine too much gas, but plenty have without having enough".

So I keep on pumping.

Dale

jmurba

Hi Dale,

I also wonder what to do.
it must also depend on what kind of dive we have to do, I ususaly dive between 45 and 90 minutes within a 20 max ascent time in shalow water.
I count 2.5 liter a minute to plan my dives.
Am I on the right track???

regards

jean mi

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iain-hsm

As this is a compressor not a booster it's designed output pressure of
155 barg (2200psig) working pressure is when using the ½ hp motor and speed reduction gear box. To increase to 207 barg (3000psig) would:

• Produce 30% more load on the motor
• Increase rod loadings
• Increase temperature generated
• Increase inter stage pressures in 2nd stage and 3rd stage

Now if you were to physically tamper and increase the pressure switch setting and final stage relief valve setting you would by doing this:

• The increased motor overload and relays now to close to trip overload.
• The inter stage relief valves (non adjustable) would be on the point of venting.
• The compressor cooling would have to be increased pro rata possible additional cooling coils or additional heat exchanger
• Rod loads are above the engineering design loading.

I hope we understand that it’s less some arbitrary bullshit warranty problem and more sound practical engineering practice and principle. Iain Middlebrook

Ben Field

Good, valid point Iain, maybe Tom was told wrongly.... shame. I'd be abit shocked if they sell something that close to tolerance though, must be some overhead allowed, I guess we're not the market it was designed for though.

Shame, 200bar would have made it useful, 150bar is flipping useless (To a diver)

Any other small electrical boosters/compressors on the market? This has been the only one I've seen.

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jmurba

Well I don't know the technology, all I know is that no system work at his limitn then the booster limit can't be 152 bars....but ok not to bad even at 152 bars

regards

jean mi

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Yankee Rebel

re: the invacare homefill....

i looked into this myself just so that i could fill med O2 bottles and use those for O2 dives. i found out a couple things..

1. they only produce about 95% pure o2.

2. the O2 cylinders they use utilize a prorietary valve on them that according to the rep i spoke with will not work in a standard post valve type yoke.

3. adapting the homefill over to use standard non-proprietary valves was considered by the rep to be a no go. we all know anything is possible, butt this is what i was told, but im still sure that someone with a lathe could whip something up.

4. the homefill and the like require an O2 concentrator as well, yet another part.

5. its still only a 2,000PSI fill

6. possibly size limited to the M6 cylinder but i dont remember. my cylinders are M9's so i really should have remembered this.

for my own O2 needs, i can live with 95% O2 in the cylinder with the remaining 5% being N2. i will flush my loop occassionally to compensate for this added N2 in the loop. for the cost of a new unit, about $3k thats quite an investment. used units can be had at significant savings if a person shops around. there are ALOT of outfits selling "used reconditioned" models at almost new prices. i did find a homefill type unit that was $1k on the used market and the company had several of them. durability and maintance i do not know about. i do know that for most peoples uses, 2,000psi will still require a booster, putting the whole thing into an area where the cost far outweighs any benifits for O2 needs over 2,000psi. for my own O2 needs, 2,000psi is enough to take care of most of them. oh yeah... you still need an O2 concentrator wich drives the prices up even further and adds one more variable to break down and go wrong..

now if i can ever manage to get the money saved for a manual booster without something unexpected happening to take that money.. ill be a VERY happy man!

Philippe GERIN

I take it this is a compressor, so you need to enter it @ a low pressure and then compress it. So that means you first need to transfill and then only, de-compress O2 and re-compress up to 150 or 200 bars. That's a lot of manipulations, especially at that price: > $3000.

I guess Tom is not available to chime in here so here is a re-print (I hope he won't mind) of an e-mail communation I had with him 2 years ago about the RIX O2 compressor:

Hello Tom,
I've seen the Rix microbooster, then I've seen that you have/had one presented on your website.
Questions:
1) did you find the pressure switch? :-)
Yes it is underneath on my model....Look below the feet to get there....
2) Have you been using it much?
I keep that unit at the office for boosting from my cascade. Since I cannot travel with full oxygen tanks anymore....It is only normally used to fill tanks for testing in the pool and quarry.....it works great but be sure to give it about 20 psi (1 bar above ambient) of oxygen pressure to make it work properly.
3) for that price (about 3 grands now), safety should be way higher than with a conventional booster (Kiss, Hydaulics Int...). What is your take on that?
I do not know about safety being better. I also have a little kiss booster I travel with. I run it at home on an oilless compressor with my home cascade and on bc connectors at dive sites where oxygen is available. I like the kiss nanobooster much more. It is lighter. It is also more fun to use....(I love the sounds it makes) I am such a child.....at 63
Last, would you recommend it?
I would recommend either as I have not had a bit of trouble with either units. They are both easy to use and do the job. They also will boost your helium...

If I only had one, it would be Gordons Nanobooster with an oilless pancake compressor (about 125 dollars at Home Depot or Lowes) (this is my rig in the basement)


So I made the same choice and run my Jetsam booster of a 10bar shop compressor instead of a scuba cylinder.
Total for the Jetsam Booster + the shop compressor is way less that the Rix, plus I use the shop compressor a lot around the house now. Well, the down side is that I HAD to buy all these shiny air powered tools

Best
Philippe

jmurba

Salut mon Ami,

Thanks a lot for your precious thought about all those problems.
in fact I am presently re-considering my filling means because of the grows of my diving activity.
after a lonelyness periode diving ccr kiss alone from shore site, one diver joined me for boat cc diving , then 2, and now 4.....all diving tecme modifies dolphins...
I are buying a mooring, purchasing a 6m open outboard engine boat etc etc...
So i need a different system to fill my o2 tanks, a slow silent and sure mean with whick I won't have to connect , disconnect connect again hi pressure hoses to cascade o2 tanks even with the help of the frau drager it wil remain a pain in the neck....
so 2 big o2 thanks ans a rix will give between 152 bars and 200 bars of o2 where 150 bars was my max o2 pressure a ressure chosen for safety reasons.....
boosting silently and at home automaticaly would be nice.
The other issue is safety, even feel like to buy a rix s4 for air and trimis compression rather then my old oil compressor, again silence, safety etc...
a cultural change.
defintely the rix compressors are interresting for me
regards
jean mi

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mikedivetech

The inherant problem of air drive boosters is now well known . With this understanding, the engineers at Stansted Fluid Power came up with a unique design for the DTB5C . Instead of using air on both the compression stroke and the exhaust stroke, (or in other words both sides of the piston) they decided to utilise the pressure from the incoming gas, and a spring to return the piston to the top of the stroke. Only 2% of the energy in the incoming air is used to depress the spring. This design makes a significant reduction in drive gas. The other key point is the fact that we have another level of seperation between the drive gas and the supply gas. Another design feature provides a double vented air space between the compression head and the air motor. These two factors together make it impossible for there to be any contamination of the supply gas. We are not just relying on the integrity of a seal . If you wish to view this booster and the larger electrically powerd booster, go to Gas booster - Trimix - Diving.

Regards

Mike McNulty
M.D Divetech ltd