O2 cylinder pressure

[broncobowsher]

I thought they just got really inefficient. Blow a lot of drive gas and move very little product.

 

[DA Aquamaster]

What is this recommendation based off of?

Interested to know the reasoning on the 4:1 ratio as well. I just picked up a Drager electric booster that is set to 4:1 with a lp supply cut off and hp shut off to keep it at a 4:1. And Im sure the Germans had a reason for it. Drager tends to over engineer everything.

The concern with high boost ratios is the potential for excessive heat due to compression that could result in ignition. I don't know if there is a definitive source, rather than just a industry best practice that states a 4:1 max ratio. However Haskel recommends 5:1 for a single stage booster, with O2 inlet pressures less than 150 psi, and 6:1 for a single stage booster with O2 inlet pressures greater than 150 psi. That said, Haskel also states:
"For heavy duty, continuously operating applications, we recommend that the above compression ratios
be reduced even further, where feasible, with additional staging and/or plenum coolers".

In that regard 4:1 is just prudent.

If you're using a multistage booster then the ratios are not a factor unless the O2 inlet pressure is under 150 psi or so and you're boosting well above 3000 psi.

Haskel's maximum recommended compression ratios:
O2 Inlet < 150 psig O2 Inlet 150 psig or Higher
Single Stage 5 : 1, 6 : 1
Two Stage 25 : 1, 36 : 1
Three Stage 45 : 1