Nitrox stick flow meter rate?

[diverman2013]

This is a short video showing the simultaneous blending of 32% nitrox into the bank tanks while transfilling four scuba tanks through the fill panel.

Nice setup. Do you happen to have a link to where you got your electric shutoff solenoid?

 

[RayfromTX]

It came used. It's an easy search though. Just make sure you get one that meets your criteria for voltage (220?) pressure and normally closed.

 

[RayfromTX]

This is an older and longer version of the whole setup including making small adjustments of the flow meter and the delayed response to the mix. The mix before the compressor and filter needs to read 33% for the final mix to come out as 32%. This is explained in the oxyhacker's companion.

 

[iain/hsm]

This is a short video showing the simultaneous blending of 32% nitrox into the bank tanks while transfilling four scuba tanks through the fill panel.

Now that's a great looking Bauer. Pity all nitrox compressors dont follow the same design principle with nitrox.
Well done Bauer for such a safe innovation. LOL

But get it on a bench or trolley or something, at least get it up off the floor
Your gonna do your back in bending down to that thing all day unless your into yoga or Mecca.
I guess you dont have any dogs cats or kid's around, the lack of a belt guard is not a pretty sight.
Now where's the kids hamster gone?

 

[RayfromTX]

Now that's a great looking Bauer. Pity all nitrox compressors dont follow the same design principle with nitrox.
Well done Bauer for such a safe innovation. LOL

But get it on a bench or trolley or something, at least get it up off the floor
Your gonna do your back in bending down to that thing all day unless your into yoga or Mecca.
I guess you dont have any dogs cats or kid's around, the lack of a belt guard is not a pretty sight.
Now where's the kids hamster gone?

The belt guard stays off. I monitor the head temps and I think the guard improves the cooling. I have a supplemental fan and up near 4500 psi the head temps measure 230, 191 and 194 for the 1st second and 3rd stages with an infrared temp sensor held in close and at multiple angles to find the highest temps. No cats dogs kids or careless adults in my office while pumping. I can still get up and down. If loading tanks in the car doesn't wreck my back and climbing the stairs at the lake with my gear on doesn't do it, I'm pretty sure draining the coalescers won't. Cheers iain! btw, serial number 6202 but with the heads and cooling coils upgraded.

 

[iain/hsm]

The belt guard stays off. I monitor the head temps and I think the guard improves the cooling. I have a supplemental fan and up near 4500 psi the head temps measure 230, 191 and 194 for the 1st second and 3rd stages with an infrared temp sensor held in close and at multiple angles to find the highest temps. No cats dogs kids or careless adults in my office while pumping. I can still get up and down. If loading tanks in the car doesn't wreck my back and climbing the stairs at the lake with my gear on doesn't do it, I'm pretty sure draining the coalescers won't. Cheers iain! btw, serial number 6202 but with the heads and cooling coils upgraded.

The Black ABS Fan Shroud (the black 14” tube) improves cooling considerably,
However the solid ABS belt guard (not shown LOL) does not, indeed it retains heat off the cooling coils and block and directs it back and also along the belt guard across to the motor.
We have considered cutting holes/slots etc but it makes the 6mm ABS weaker. also using steel internal supports

An open mesh (invisible to air) guard it what may be needed for yourself but for us the solid ABS moulding is cheap and easy to make and assemble, besides heat isn’t the major consideration with the rings on compressed air applications. Some were built with two (2) computer fans fitted to the back of the belt guard outboard, I have a photo to pull/push the hot air across the guard and out the back. The mod used an aluminium flywheel and crankshaft and was an “open” spoke and balanced hub pulley than the solid metal twin belt version used on the later models.
A finned version of the open flywheel was also on the drawing board as was an overdriven fan
but they never made production.

The solid metal counterbalanced pulley gave balance against the front swash plate fan end bearing, but using the open hub pulley (as yourself) needed an offset balance weight fitted flywheel end, that some folk liked to fit upside down so in addition to kneeling down on the floor your also left crawling around chasing after the thing when running.

Anyhow I have an announcement I should make on the Rix SA Series on another post so will do it later and not go off topic here.

 

[tbone1004]

@iain/hsm please have that announcement be a reasonably priced parts source.... I have two that I can't justify rebuilding because it will be about $1500 in parts, each....

 

[RayfromTX]

The Black ABS Fan Shroud (the black 14” tube) improves cooling considerably,
However the solid ABS belt guard (not shown LOL) does not, indeed it retains heat off the cooling coils and block and directs it back and also along the belt guard across to the motor.


Anyhow I have an announcement I should make on the Rix SA Series on another post so will do it later and not go off topic here.

That was the conclusion I came to as well. I am hoping the measures I've taken along with the ambient temperature of 71 degrees while running will help push the routine rebuild of the unit far off into the future. We have indeed dragged this thread off topic but I appreciate your input and I hope the OP got the answer he was looking for and more. I look forward to your announcement on the SA series in the post you mentioned.

 

[iain/hsm]

@abnfrog I remember that thread and I remember that your tech never actually said why. He may have convinced you, but you didn't relay to us why other than there was a nitrox specific block and left it at that.
There are tens of thousands of cubic feet of EAN32 being pumped through standard Bauer compressors every single day and I have yet to hear of one blowing up as long as it was done properly *i.e. O2 shutoff tied to the compressor shutoff so you don't blow straight o2 into it*

So please enlighten us here on what convinced you to stop continuous blending?

From Bauer's website
Same blocks, they just undergo an ultrasonic cleaning step. You have filter stacks and coalescers for oil removal, not concerned. It also doesn't stop oil going past the rings
Lube is all O2 compatible which can be done on any compressor at service time. That said, we are talking about sub 40% nitrox mixes that don't require O2 cleaning, so as long as you have an O2 shutoff to not dump pure O2 into the thing when it shuts off, all is well in the world.
Temp monitoring and maybe some extra cooling capacity that the other models don't have. That's nice, but you can hit it with an IR thermo if you're concerned. If you're really worried, for about $200 and a few hours of your time you can build a relay system with a raspberry pi that has however many thermocouple probes you want that can be tied to the shutoff circuit for the compressor. Bit ghetto compared to Bauer's solution, but just as effective.


edit: here's the thread for anyone curious. Really nothing good in here other than people trying to CYOA/Bauer getting TUV SUD certification on those blocks
nitrox blending

To get back on track regarding Abnfrog's excellent point regarding service failures and the real cost to the block of pumping nitrox with an oil lubricated compressor.

From memory there were twenty (20) or thirty (30) serious engineering considerations given why you shouldn’t be pumping an elevated oxygen concentration (Nitrox) through an oil lubricated air compressor. I listed them some years back on a Coltri block post, the list was so long it took up the full page.

Yet not one of them was the obvious, oxygen fire/explosion or the likelihood of a fire or explosion its way more subtle than that.

There was also before the fire argument in addition about ten (10) or a dozen reasons given why you shouldn’t pump nitrox in a oil lubricated compressor and incidently ultrasonic cleaning of the block addresses only one of them.

Although I know I'm running off topic again I just dont think enough information is out with the public for them to make an informed choice.

Non the less Abnfrog made an excellent point its costing you guys much more than you know doing this stunt in a Bauer or Capitano or Coltri and as any compressor service tech will tell you
Go right ahead pump it at your leisure, you making us a good living.

Gabel, H. and Janoff, D., "Use of Oxygen Enriched Mixtures in Recreational SCUBA Diving—
Is the Public Being Informed of the Risks?,"Flammability and Sensitivity of Materials
in Oxygen Enriched Atmospheres: Eighth Volume, ASTM STP 1319, William T. Royals,
Ting C. Chou, and Theodore A. Steinberg, Eds., American Society for Testing and
Materials, 1997, pp. 34-41.

 

[BRT]

To get back on track regarding
From memory there were twenty (20) or thirty (30) serious engineering considerations given why you shouldn’t be pumping an elevated oxygen concentration (Nitrox) through an oil lubricated air compressor. I listed them some years back on a Coltri block post, the list was so long it took up the full page.

Yet not one of them was the obvious, oxygen fire/explosion or likelihood of a fire or explosion its way more subtle than that.

There was also before the fire argument in addition about ten (10) or a dozen reasons given why you shouldn’t pump nitrox in a oil lubricated compressor and incidently ultrasonic cleaning of the block addresses only one of them.

And yet it is done on a daily basis by many thousands of compressors running in all kinds of conditions all over the world with few problems.