Oxygen analyzers--which type is better?

[pescador775]

The Miniox III is a very expensive medical unit which shows up on EBay for little money, about $100. The Miniox I is simple and sells for about $70, both less sensor, about $45 extra. The Expedition by Oxycheg sells for $300 retail with sensor included. The Analox sells for about $265 including sensor but I paid $215.. My total investment for the Miniox III used on my Nitrox stik plus the portable analox (for travel and general locker use) is $100+45+215 = $360.

I say, if you can get an oxycheq for $200, it would be an attractive price.

 

[Quaack]

I just built the el cheapo kit from Oxycheq.com.
Put it together in about 2 hours, seems to work good.
I got the tee fitting that you just hold up to the valve,
but depending on flow, the reading varyies.
I just got the bc inflator adapter, it is a set flow,
so I hope for a more consistant reading.

Dave

 

[pescador775]

The key to consistant readings is to limit flow. This can only be done coarsely by adjusting the valve, just too much brute force behind it. Vance's book shows some useful things including a restricted flow adapter. Basically, one needs a dome shaped plastic fitting with a 3/8 npt thread on the back end. In the apex of the dome, drill a #60 hole or a bit smaller. In the side of the dome, drill two 3/32 holes. Screw the sensor into the back of the dome. Measure gas % by pressing the dome against the valve orifice. I noticed that new valves are sometimes especially difficult to control---it depends on the brand. The analox uses a pretty SMALL inlet hole, it is #64. With this device, it doesn't matter how cranky is the valve, it gets a good reading.

 

[Quaack]

Just got back from LDS, got a SS1 type fitting for my adapter.
Works great, just turn it on. No guesswork. Consistant reading.
I had a tank filled w/ air that previously had 32% with 1500 or so remaining,
it's now 28%.

Dave