Oxy Hackers Nitrox Stick

[RayfromTX]

Pumping Nitrox - YouTube

• RayfromTX
• Aug 18, 2017

Filling the cascade with 32% while transfilling four scuba tanks

 

[Chris H]

IMG_1746

• RayfromTX
• Aug 17, 2017

IMG_2450

• RayfromTX
• Aug 17, 2017

Thanks for the photos, but I was curious about your odor free inlet tubing. What did you end up going with? Thank You.

 

[BRT]

I'd like to ask if anyone has built a nitrox stick that they had reason to believe didn't mix well enough? My thought is that as you are feeding the O2 in at positive pressure and the correct rate the stick will always find the right amount of air to mix with it.

 

[rjack321]

I'd like to ask if anyone has built a nitrox stick that they had reason to believe didn't mix well enough? My thought is that as you are feeding the O2 in at positive pressure and the correct rate the stick will always find the right amount of air to mix with it.

The volume of air will be mostly correct (although as pressures rise the total volume does decline slightly due to piston blowby)

The stick is to ensure that the volume of air and O2 get fully mixed so your compressor 1st stage doesn't see a slug of >40% O2 and lead to an explosion. You don't need that many baffles since once turbulent flow is established you'll get enough mixing - if the stick and inlet hose are long enough to provide the dwell time for the turbulence to completely mix the gases.

My 3.5cfm unit has a ~18" stick with 2 oxyhacker type drilled baffle caps in it. 2 baffles per cap. Then about 8ft of 1-1/2" PVC hose.

 

[BRT]

The volume of air will be mostly correct (although as pressures rise the total volume does decline slightly due to piston blowby)

The stick is to ensure that the volume of air and O2 get fully mixed so your compressor 1st stage doesn't see a slug of >40% O2 and lead to an explosion. You don't need that many baffles since once turbulent flow is established you'll get enough mixing - if the stick and inlet hose are long enough to provide the dwell time for the turbulence to completely mix the gases.

My 3.5cfm unit has a ~18" stick with 2 oxyhacker type drilled baffle caps in it. 2 baffles per cap. Then about 8ft of 1-1/2" PVC hose.

The volume of air will be exactly correct for whatever nitrox level is leaving the compressor. It is impossible for the compressor to get pure oxygen so long as you do not turn the O2 on before you start pumping. Unless you think the oxygen might fill up part of the pipe while air got by it and then suddenly change the flow pattern in the pipe so the pure O2 got sucked in all at once. I just think that is unlikely and we probably go overboard with the mixing.

 

[rjack321]

The volume of air will be exactly correct for whatever nitrox level is leaving the compressor. It is impossible for the compressor to get pure oxygen so long as you do not turn the O2 on before you start pumping. Unless you think the oxygen might fill up part of the pipe while air got by it and then suddenly change the flow pattern in the pipe so the pure O2 got sucked in all at once. I just think that is unlikely and we probably go overboard with the mixing.

Like I said...
Once you set up turbulent flow the gases will mix given enough dwell time. You don't need 20 baffles unless you have a short stick on a huge compressor with a short intake hose. People do get excited (or paranoid) about their new CB systems and add a ridiculous number of baffles which only serves to increase the vacuum on the intake.

 

[RayfromTX]

Thanks for the photos, but I was curious about your odor free inlet tubing. What did you end up going with? Thank You.

For anyone interested, I found the right hose at Nuvair.