Trimix/Helium analyzer questions

[Wookie]

They pump more banked Nitrox than anywhere else in the world.

Maybe, but I'd want more data.

My Analox has been great, but I go through He cells every couple of years. Maybe because I use it a hell of a lot? Still a great unit.

 

[DA Aquamaster]

Way back in the day when a group of us started partial pressure blending our own trimix in the middle of the country where no one sold it, helium analyzers were not common and were very expensive. The general concept then anyway was that as long as you got the math and the pressures right, the final mix would be correct - and you could use the O2 analysis as a general check. Back stopping that was the reality that being 5% off one way or the other on your helium has very little impact on deco obligation. None of us died so it must have worked.

However, that approach is very antiquated when you consider that helium analyzers are now readily available at <cough> reasonable prices in the $800-$850 range. It sounds like a lot of money but if you're diving trimix, it's not going to be one of your major expenses over even the first year of trimix diving. And with the increased use of stick blending, the need for your own analyzer is even more important than in the past. Today, there is no way I'd dive trimix without access to a helium analyzer.

I bought an AII Trumix 4001 at DEMA a couple years ago. It's been very reliable and is extremely easy to use with both BC QD restrictor and direct to the valve sampling options. The O2 sensor has a 5 year life while there is a 10 year life on the Helium and environmental sensors. The only issues I've had was an O2 sensor died at a little over a year (but AII sent me a new one at no charge) and the battery needs to be cycled a couple times to come up to capacity after sitting a few months. They indicate they use a lead acid battery, so I'll have to check mine when I get home as mine acts more like a NiMh battery and they may have changed it.

It's basically idiot proof, is very easy to calibrate and comes in it's own water tight case. In that regard it offers a great alternative to the more common Analox analyzers and it automatically compensates for temp and humidity when it calibrates, so there's no need to use a chart.

http://www.youtube.com/watch?v=47nBfiCWcWQ

 

[manni-yunk]

The real question is - does one really need a helium analyzer? If the O2 is correct, aren't the others? I am off to DEMA next week and this is one of the top things on my list. As a dive shop I do need to provide one for my trimix courses, by standards, but helium analyzers are relatively new on the market. I see some folks are now offering a trimix stick for blending, which worries me. I am not really a fan of O2 going through my compressor and I think helium would also be problematic. But, these again are research topics for DEMA.

I know there are ways to blend and not "NEED" a trimix analyxer - but - I would feel safer with one.

As to the o2 going through you compressor - doesnt it go through your compressor now (21%) -If you believe that anything at or below 40% behaves and should be treated like air (although Ive sen a paper that said this number should be anywhere from 23% to 60% - I feel comfortable with 40 and most people seem to) - than its the same thing. . I have been continuous blending all summer and its easy. Harlow's book (Oxyhacker)makes it dummy proof and as long as you use the correct oil, and keep the O2% at or below 40% - it doesnt seem to be a problem. I know a lot of people blending through a compressor this way.

Im not sure if I will add the additional nipple and add the trimix through the compressor - but I am leaning that way.

 

[Tug]

I know there are ways to blend and not "NEED" a trimix analyxer - but - I would feel safer with one.

I'm the same way when I got mine. I've found that I've used it the more than I expected, especially when I top off with air or when it's been a little while since I got the tanks filled. If anything I think it's worth it for the peace of mind alone.


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[NAM001]

I WOULD not think there would be an issue pumping he, as it is neither hydrogen or o2. the only problem for long pumping periods is heat buildup in the compressor. part of the compressor cooling is the humidity in the gas being pumped. It is the same issue with o2. and you can always pp blend till you have to use the compressor. If we could all just have boosters.

 

[SeaCobra]

I must have misunderstood your question. You are a NAUI Course Director and NAUI Tech Ops, so I am sure you know the answer to this question. You analyze your mix with an oxygen analyzer to check oxygen ONLY. If you use only an oxygen analyzer, a reading od 21% could be air or trimix. BIG DIFFERENCE!

I am glad you use an trimix or helium analyzer for your trimix classes. Please continue to do so.

Well, to borrow your quote, 'lighten up Francis' and clamor down from your pulpit. What do you think we did before these trimix analyzers were available? Blending trimix is an artform not for the lazy or sloppy, care must be taken to pay attention to pressures and temperatures of all gasses and tanks involved. Put the helium in and then the O2, allow time to homogenize and then analyze. You should get a specific reading, then top with air, allow time to mix and analyze the O2 again. This method works quite well and is pretty reliable for starting with empty tanks. And it was what we used when I took my course.

Naturally, if you are going to get complicated and change mixes, etc., a trimix analyzer would be advised. I am merely posing the question, does the average joe diver need one of these things? Maybe, maybe not. I'm just tossing out some options.

And yes, I am a NAUI Course Director and a NAUI Tec Instructor and I do use a trimix analyzer for all NAUI Tec courses.