Nitrox Stick Oxygen Mixing Issue

[ForceRecon1Co]

Hello all,

New to the forum, so I’m sorry if I posted thread in wrong section.

Just built a new “
Michael McFadyen” style Nitrox Stick and I’m having a bit of a mind boggle with its operation.

Also bought two new NRC Analysers (I know they’re cheap, but work). I’ve testested them both with ambient air and pre-filled 32% Nitrox tanks, both read 21% with ambient air and 32% off the air in tanks.

Here’s the query:

- Turn On compressor with bung in analyser port and fills tanks correctly. Then (without oxygen ON, or even connected to stick), take out bung, insert analyser, and get 21% oxygen reading...everything good at this point.

Then without even plugging in oxygen line the analysers will both read 21% oxygen for about 20 seconds then start climbing 1% oxygen about every two seconds until the max out...at about 97-98%...

How is the oxygen rising in the mixing stick to the output without an oxygen supply?!?!

It’s built to specs, two new NRC Analysers, and still this issue persists.

Any assistance much appreciated!

Thanks mates!

 

[Asheron]

Maybe you have a static discharge issue? Try maybe grounding the outside of the stick or bonding it to the compressor?

The oxygen sensor is current source that is then turned into a voltage. So the tool is looking for a mVolt reading and maybe the static electricity being generated by the air through the mixing stick is messing with the reference point of the meter.

 

[BRT]

Please remember to tell us when you figure it out!

 

[ForceRecon1Co]

Thank you, will try this back in port in Benoa, Bali in a couple days. I’ll keep you posted!

 

[ForceRecon1Co]

One question (as I’m not an electrician by any means), but do you ground PVC in the same manner as metallics.

So I’d just stick a bolt in the end with a grounding cable to the metal on the deck or on the compressor itself?

Thanks!!!!

 

[Asheron]

Maybe duct tape a bare conductor to the length of the pipe and then bolt it to the frame of the compressor/deck.

I personally am not familiar with grounding PVC but woodworkers who move dust using PVC ground their systems.

Just go cheap on this as I am blindly guessing your problem.

 

[ForceRecon1Co]

Sounds like a plan. I’ll keep you posted. Thanks to all!

 

[JackD342]

How to Ground a PVC Pipe | eHow

 

[ForceRecon1Co]

Right on...Thank you!!!

 

[ForceRecon1Co]

Ok all, an update on the situation. I looked into all options that were provided, but came up with a new solution that’s working great. Although the solutions provided by the members were all viable and doable, I just wanted to keep a neater (cleaner) appearance of my dive locker with less “going on” in there...

So, instead of grounding out the system to get rid of any static interference I did the following:

1. Cut off bottom “cap” from stick and replaced with a sealed screw cap instead (this gave me easier access to the internals for cleaning, etc.).

2. Took out mixing baffles as I’ve seen using wiffle balls as a more “proficient” way of mixing air, gasses, etc.

3. Instead of wiffle balls I used drier static balls. These give the same premis of the mixing effect while absorbing the static interference.

These static balls will need to be replaced periodically (will update once I see how long they last under use), hence why the screw cap was installed instead of a permanent cap.

All is working well and I greatly appreciate all the feedback and assistance with this project. I hope this helps anyone in the future and I’ll continue to update everyone if this is a suitable (efficient) solution.

Thanks to all!

Cheers