Question Idle question from a possibly addled mind

[JohnN]

Is a RIX SA-3 suitable for use as an O2 booster. I have no plans to get into rebreathers, just curious

 

[rjack321]

Is a RIX SA-3 suitable for use as an O2 booster. I have no plans to get into rebreathers, just curious

No! You feed a compressor ambient pressure and it makes 250-300bar output from that. That is minimum 10x more than any recommended O2 compression ratio and creates an obscene amount of heat (at least for O2).

In booster terms that is like taking 250psi supply and creating 3000psi output - which is not a good scenario.

 

[iain/hsm]

Is a RIX SA-3 suitable for use as an O2 booster. I have no plans to get into rebreathers, just curious

No the Rix SA-3 is an air compressor. Read the label

But having said that if you pushed it up on the black board for an engineering review and purely on sound engineering practice and principle to explore the principle differences from a design philosophy (DP) perspective. Again it's a no go but from the DP position to make it work on oxygen the following would be required.

Take the 3 basic aspects of any scuba compressor
1. The Piston sets or diameters of each piston together with the number of pistons
2. The Piston stroke (Piston length of travel from Top dead centre TDC to bottom dead centre BDC
3. The RPM of the block

Then the only component of your SA-3 you could use to kick off with would be the 3rd stage piston diameter. But the Piston stoke you would have to double in length and the RPM you would have to slow right down from 2300 RPM to less than 200 RPM to get the same flow so that's the block ditched and your onto a new block design from the get go.

Although this would give you a near equivalent flow as your SA-3.

Now the problem is that the 1st stage now won't help you so you would have to ditch it off the drawing board as well and pushing the inlet pressure up to say 60 psi on the inlet stage to compensate. Or say down to 25psi to make the design really good as a scavenging pump.

Now with the 1st stage ditched the 2nd stage piston is now acting as the first stage and its now too small a diameter so a new inlet piston diameter is required.

Then add similar consideration to the valves heads pipework cooling interstage compression ratio, heat loading, cooling considerations etc.

Then in addition add the customers service life expectations, service components cost to customers, any special considerations or special tools required or be needed to service, Any practical oxygen cleaning procedure difficulties they may have etc. etc.

You get the picture

Then add any additional safety features low inlet cut out, high discharge pressure cut out, a high temperature RTD monitor and again another cut out. A micronic inlet particulate filter and the same on the discharge side. Include in your design criteria a 24/7 hours 100% duty cycle at 200 bar 3000 psi discharge pressure.

With all that junk your now double the weight of your original SA-3 and cost and you still need an ambient pressure air compressor for your air cylinders.

But at least you know it can be done just one part at a time.
At least it would have an oxygen label on it saying

This is an oxygen compressor not an ambient air compressor
Do not use at ambient inlet pressure

Just saying before someone asks if it could be used as an air compressor LOL

 

[JohnN]

No the Rix SA-3 is an air compressor. Read the label

. . . snip. . .

Speaking of the label:

I'm continuously blending EAN (32%) with no apparent problem, and the previous owner used it for tri-mix. Thank God I no longer dive with split fins. . .

But thanks for the other comments and engineering analysis.