How much an enhanced DIY version of a Trimix stick would cost ?

[Darghu]

Hello.

I played a bit with Google image to found some Trimix stick blend system for a DIY Home Filling Station and I have found this product from Nuvair. I got a reseller who sell this 13 500 € w/ shipping - taxes.

I am wondering if a DIY version (low cost, but quality componant) would be better in term of price or customization. This picture show only for Nitrox but a Trimix version would be possible right ?

What is the "Heater componant" ?
What is the "Membrane and the Nitrogen Discharge" ?
What's the deal with the Thermostast control ?

Thanks for your help.


Here are parts (often edited)

Analyzers/Sensors:
- 4x Oxygen Sensor (2 inside Trimix Stick + 1 before Tank + 1 before Nitrox/Trimix Bank)
- 1x CO2 / CO / VOC gas Detector (Room Ambiant Air - near Compressor)
- 1x CO2 / CO / VOC Sensor (after compressor)
- 1x Portable Trimix Analyzer (%02 %He %CO2/CO)

Filters:
- Bauer filters : LAWRENCE FACTOR® – High Pressure Filters
- Alkin filters : LAWRENCE FACTOR® – High Pressure Filters
- 1x Personal filter + Consummable Filtre personnel
- Compressor ' Air Intake (Air taken outside)
- Additionnal filters ?

Where to buy?
- McMaster-Carr



Nitrox Systems – Nuvair

 

[elmo]

That looks like a membrane system. The only intake is air, and the membrane separates out some of the nitrogen, leaving you with nitrox.

A simpler diy system is to add a nitrox mixing stick to the intake of a standard compressor. You feed in pure o2 (from a cyclinder), and the stick mixes it with the air on intake. Have an analyzer between the stick and the compressor intake. Be careful not to mix in too much o2 and be careful with the compressor lube or it could go bang. 32% is good, 36% is ok if you're careful. Anything richer and you're asking for trouble.

I've not seen a trimix mixing stick myself, but the principle is the same. You need:
Compressor
Mixing stick
Analyzer
O2 supply
He supply
Hoses, fittings, etc.

The principle isn't complicated, but getting it right can be, and getting it wrong can be dangerous.

A very clever guy in Australia sells mixing kits, or separate parts, depending on what you already have. Not sure what what the cost of shipping to France would be, but given the outlay it may be ok. Or just look at his catalogue for ideas if you think you can make it yourself. The continuous mixing stuff is on page 30. AU$1 ~ 67 Euro cents.
http://www.tfmengineering.com.au/TFM Engineering Catalogue 2017-03.pdf

 

[Darghu]

Be careful not to mix in too much o2 and be careful with the compressor lube or it could go bang. 32% is good, 36% is ok if you're careful. Anything richer and you're asking for trouble.

This is a good point and this is why I wonder if a clean DIY project (decent separate parts price + homemade) would be great even if it's not from a "expensive" product. If those parts must be O2 clean It will be done.

A very clever guy in Australia [...]
http://www.tfmengineering.com.au/TFM Engineering Catalogue 2017-03.pdf

I put into my watch list here are additionnal infos I have found.
Continuous Mixer/Mixing Kit/Stick for SCUBA Nitrox/Trimix/Gas Mixing | eBay
tfmengineeringaust on eBay

Shipping cost would be AU $114.05 / EU €76

Thank you for the website and PDF I totally forgot to check that.


I added at least - sensor/detector and filters ideas...

 

[tbone1004]

Tri-Hunter 6000

quite a bit less expensive at $3200 and has solenoid control for both He and O2

 

[Caveeagle]

Tri-Hunter 6000

quite a bit less expensive at $3200 and has solenoid control for both He and O2

Pretty cool system, and you would be hard pressed to find a mixing set-up with a better track record.

 

[Darghu]

What do you think of this :
MPS Technology Mixer Expedition - Proteushop @ us$5300
http://www.mpstechnology.it/en/mixer/mixer-case-1

Mixer King @ us$3900

 

[tbone1004]

never seen them or heard of them, but we don't get a lot of cross pollination from Europe over here on that kind of thing due to the exchange rates, but the concept to build them isn't particularly difficult so I wouldn't have an issue with them. I'm sure they work well.

 

[Darghu]

Thank you for that report.
About filtration system, how would you describe a good filtration system ?

(Air intake filter) >> HP Compressor >> (Post-Compressor filter) >> ---- going to Air / Nitrox Bank

Air / Nitrox Bank >> Mixing tube >> (Post-Mixing tube filter) >> ---- going to Mixed gaz bank (if needed)

Mixed Gas bank >> Mixing tube (O2+He) >> (Post-Mixing tube filter) >> (PERSONAL FILTER) >>> DIVER TANK


* Air intake filter do reduce air ambiant pollution (particles, CO2, humidity)
* Post-compression filter do reduce / remove CO, CO2 Oil, Humidity, Particles, Volatil Organic Componant
** Air / Nitrox Bank should have good air quality
* Post-mixing tube, (add O2 / He), and reduce / remove other things (?)
* PERSONAL FILTER when filling the diver tank

 

[tbone1004]

usually no serious filtration on the intake side, but if you have a pre-filter it's always ideal

mix stick before compressor obviously

compressor with water traps

filter stacks *important that these be after the compressor for dwell time

banks/outlet


personal filter isn't that important unless you don't trust the main filters or you need to keep a tank oxy compatible but know the air isn't oxy compatible

 

[Darghu]

By any chance do you have an example of a pre-filter for in-take ?
noted for water traps

What about CO/CO2 absorption can it really be 0 ppm for both ?