Continuous Tri-mixing

[manni-yunk]

Ive been continuous blending nitrox all year - and it has worked out great. Im now about to set up a bank system and I am going to bank trimix. I have read Oxyhacker. Do any of you guys continuous blend trimix with a stick?

Are there any risks to the compressor other than those associated with Nitrox at < 40%?

 

[Wookie]

You really want to make sure your helium is really well mixed in the stick, and there is no helium stream going into the compressor. Helium is really cold, and will tend to chill one edge of te intake valves, causing thermal distortion. If you have any carbon from your nitrox blending, it could cause the carbon to flake off the valve. It could crack the valve in extreme cases, not the end of the world, but the PITA factor is high.

 

[manni-yunk]

You really want to make sure your helium is really well mixed in the stick, and there is no helium stream going into the compressor. Helium is really cold, and will tend to chill one edge of te intake valves, causing thermal distortion. If you have any carbon from your nitrox blending, it could cause the carbon to flake off the valve. It could crack the valve in extreme cases, not the end of the world, but the PITA factor is high.

According to what Ive seen posted by other tri-mixers...Bauer actually said its OK to blend Helium through the compressor - BUT - they are still not approving Nitrox. Is the statement that Bauer condones helium through the compressor accurate?

Im not concerned with the nitrox.

Im on the verge of buying a Bauer 8.4 for my garage and setting up a bank of trimix.

 

[Wookie]

I CB Trimix through my compressor when I have OC divers and need to refill the banks super fast. Just make sure your stick is up to the task. I've seen many sticks built that allow gas streaming because of poor design.

 

[rddvet]

Good discussion. I'll be considering trimix mixing at home soon. I'll be doing so little of it that I've considered pp mixing as opposed to going through the process of reconfiguring my stick. I know the biggest negative of pp is not using all of the contents of the bottle but I've got easy access to helium with cost not being a huge factor and a booster maybe in my future regardless. Any other negatives to pp over continuous. I'm sure I could easily reconfigure my stick but am concerned about the issue of a cold helium stream causing thermal warping if not mixing well. My compressor is just newly returned and I'd prefer to keep it that way. My Bauer tech also warned me about some of the helium issues in regards to compressor health.

 

[trident00]

I would have to agree with Wookie about the danger to the valves if your helium streams or gets to high in concentration. I had a reed type valve fail while continuous blending trimix. My mixing stick does a good job, but the helium got a little bit off balanced while I was dialing it in. Go very slow when bringing on the helium and give it time to get through your stick. I have heard from many others that they prefer not to continuous blend the higher helium mixed.

My mixing stick is dialed in for EAN32, and that is what I bank. It makes blending standard trimix mixes very easy. I fill the tank with helium first and then top up with EAN32 from the compressor or bank. I bank 17/48 trimix, and can easily blend it up or down with helium or EAN32. This type of partial pressure filling requires no 100% O2 aside from the low pressure going to the mixing stick.

Good luck with it. Cheers

 

[rddvet]

I would have to agree with Wookie about the danger to the valves if your helium streams or gets to high in concentration. I had a reed type valve fail while continuous blending trimix. My mixing stick does a good job, but the helium got a little bit off balanced while I was dialing it in. Go very slow when bringing on the helium and give it time to get through your stick. I have heard from many others that they prefer not to continuous blend the higher helium mixed.

My mixing stick is dialed in for EAN32, and that is what I bank. It makes blending standard trimix mixes very easy. I fill the tank with helium first and then top up with EAN32 from the compressor or bank. I bank 17/48 trimix, and can easily blend it up or down with helium or EAN32. This type of partial pressure filling requires no 100% O2 aside from the low pressure going to the mixing stick.

Good luck with it. Cheers

Do you have a booster so you're not wasting tons of helium, or is it really not as big of an issue as people make it out to be?