O2 'Loss"

[Waterlizard80]

I do continuous blend with a coltri mch-6. I can consistently observe about a 1.4 - 1.5 % 02 'Loss' as the gas gets compressed. 33.5% goes in to the intake as measured by 2 different o2 analyzers. 31% consistently comes out. Can someone explain whats going on? Is there something with the filtration (CO, Desiccant, activated charcoal canister filter) that's absorbing some of it? Just curious.

 

[Tracy]

It is probably the design of the nitrox stick. You are getting some raw oxygen past the sensor causing it to read higher than after it is completely mixed on the outlet. The other option is a leak on the intake side between your inlet sensor and the actual compressor inlet.
Some loss is always normal with a stick, I run about 0.4% lower than my sensor reads. 1.5% seems high.

 

[Waterlizard80]

It is probably the design of the nitrox stick. You are getting some raw oxygen past the sensor causing it to read higher than after it is completely mixed on the outlet. The other option is a leak on the intake side between your inlet sensor and the actual compressor inlet.
Some loss is always normal with a stick, I run about 0.4% lower than my sensor reads. 1.5% seems high.

Awesome I'll check my fittings and retape everything. That's good info to know. Thanks for the helpful reply.

 

[windyairman]

How about piston blow by
Try to put o2 sensor on the small vent pipe from crank case.
Its a quick easy check.

 

[Tracy]

How about piston blow by
Try to put o2 sensor on the small vent pipe from crank case.
Its a quick easy check.

Unless it is the first stage piston, the loss will be equal between the oxygen and nitrogen. You will probably have what you are blending coming from the vent, ie 32%.