anybody owns a mobile compressor?

[JS1scuba]

Re what direction a trimixer should point, this is the subject of much casual discussion but I have yet to find a definitive answer. The nice thing about it is that it is one of those things everyone can decide for themselves - try it both ways and see if it the mix changes!

You need a analyzer on the input side, if only because it gives you a fighting chance of ripping the input hose off or killing the motor before an O2 spike makes it into the compressor - a downstream analyzer only tells you where you've been, not where you are going. Easy enough to add one if you don't have one already, since you can use the same analyzer for checking tanks.

Just a note here. The TDL-TekCheck Oxygen-Helium Analyzer is a flow through unit that will work under continuous flow. These are perfect on the input side of a continuous blending set up. You can run it for up to 4 hours before needing a recharge.

Regards,

 

[sciencediver1]

Re what direction a trimixer should point, this is the subject of much casual discussion but I have yet to find a definitive answer. The nice thing about it is that it is one of those things everyone can decide for themselves - try it both ways and see if it the mix changes!

You need a analyzer on the input side, if only because it gives you a fighting chance of ripping the input hose off or killing the motor before an O2 spike makes it into the compressor - a downstream analyzer only tells you where you've been, not where you are going. Easy enough to add one if you don't have one already, since you can use the same analyzer for checking tanks.

Thanks for the input Vance. Just for clarity, I already have an O2 anylizer on the stick between the compressor and the stick to ward off O2 spikes. I watch it like a hawk. This is an Oxycheq EC II Kit which I built and wall mounted. I have a second one on the step down regulator for the down stream end. The diagram in your book shows a second up stream anylizer on the premixer too. Do I need this 2nd up stream anylizer on the premixer? After reading the section on Trimixing with the stick several times, it looked to me like the premixer O2 sensor was there to assist setting the mix if a Helium anylizer wasn't available. I have a Helium analizer down stream in addition to two O2 analyzers, one up stream at the stick output, and a second down stream. I don't need a third O2 analyzer on the premixer do I? Also, while we're at it...I set the upstream O2 anylizer to 20.9%, then when I start the compressor...my up stream anylizer setting drops about 3% and reads ~17.9% when the compressor is running. Any idea why this changes from compressor off to on? I have been leaving the up stream anylizer alone and throttling my 02 up slowly to the desired mix as shown on the downstream anylizer, which seems to require me to set the 02 as shown on the up stream anylizer about ~2-3% below the desired mix. The down stream anylizer makes the mix very accurate. I mainly wonder why the up stream 02 anylizer setting drops upon starting the compressor. Could it be my stick is too baffled. I built it exactly as you show in the book. Same cap type baffles with tape to make them fit tight. It has some mild resistance, but not much more then a scuba regulator. Should it be baffled totally along the full length or should I remove a few? I couldn't decide from looking at the drawing, if the baffles are continous or if you want a few open spaces or chambers inside. Thanks in advance for your follow up. Craig