LMNT King helium rising while continious blending

[Andrius Be]

Recently I have assembled a continious blending system. It runs on MCH6 Comtri 1 phase electrical compressor. I did some measuring and it does 90-100 l/min output. For blending I use LMNT King blender . Now I set both O2 and He limiters to run 2 bar. Adjust the needle valves on King to be output 18/45 mix running on idle. For a try out I had an empty 3l tank. While running the continious mix I noticed that He was constantly rising, like 1% every 30 bar. I had to reduce an ammount fo He constantly to stay in 45 % range . Is it related to presuure ? Is MCH6 not performing ? Blowback maybe ? Whats causing it ? Its really annoying to stand there and monitor King and reduce amount to stay in limits.

 

[Tracy]

Your mch6 is not a continuous output. The motor/engine is probably slowing down as pressure increases. That is coupled with the blowby of the compressor increasing with pressure. Those add up to needing lee helium at higher pressures.

 

[Andrius Be]

Thanks for explanation Tracy. Looks like my initial gut feeling was right. I guess now there are just two wsts to remedy this situation.
1) Buy a better compressor
2) Add an electronic flow adjustment. Saw some diy solutions on internet , involving stepper motors

 

[Tracy]

Thanks for explanation Tracy. Looks like my initial gut feeling was right. I guess now there are just two wsts to remedy this situation.
1) Buy a better compressor
2) Add an electronic flow adjustment. Saw some diy solutions on internet , involving stepper motors

Most breathing air compressors are going to lose output as pressure climbs. You could definitely find a better compressor than an mch6, but even full sized commercial machines drop some.

 

[rjack321]

There is no compressor in the world that you won't need to twiddle and adjust the mix as the pressure rises. Standing there and keeping watch on it is the price you pay to play.