Regulator query

[Paul94]

I require a pressure reducing manual spring loaded regulator to control the drive gas pressure for driving a medical ventilator inside a pressurised hyperbaric chamber. The drive gas pressure for the ventilator needs to be 4 bar. The drive gas supply line to the regulator will be 50bar supplied from an outside line penetrating (gas tight seal) the chamber wall to within the chamber.

Assuming the pressure within the chamber is 20bar, does the outlet of the regulator need to be 4bar or 24 bar ?

 

[rconnor]

May I ask what application requires a 20 bar chamber? That's high enough that I would ask whether the ventilator can withstand the pressure. I'd suggest contacting the ventilator manufacturer about that first and then your original question.

 

[Paul94]

Chamber is a hyperbaric chamber for saturation (deep sea) divers. The ventilator has been checked to work at these pressures.

 

[rconnor]

Ah, I was thinking it might be for medical hyperbaric oxygen therapy and was a little concerned about the poor patient under 20 bar…

It all depends on under what conditions the 4 bar requirement was determined (i.e. is it designed and therefore tested at 20 bar or was it tested at atmospheric conditions at sea-level) and whether the ventilator is expanding/working against the 20 bar chamber or something closer to atmospheric (it sounds like the former but it’s important to understand this first). Once you figure those out, you should have your answer. Not being able to see the system, I cannot really help much more.

Also, maybe people in the marine/ocean engineering forum would have a better conceptual understanding than I do.