Rebreather World - View Single Post - More qualitative testing results on Porter VCD1000 MCCR valve

SimonK · 22nd August 2007, 10:07

Some more thoughts on how this thing works.

We have a laminar flow device with a built in regulator that controls the pressure drop across it to give constant volume flow.
The input pressure is ambient plus the O2 reg IP. Assume the IP is 10 bar and the drop across the device is adjusted to 1 bar to give the desired surface flow rate. At the surface the input pressure will be ambient (1 bar) + IP (10 bar) = 11 bar. At 40m the input pressure will be ambient(5 bar) + IP(10 bar) = 15 bar. So the mass flow of oxygen will be 15/11 = 1.36 times the surface mass flow.

Dodgy physics aside the thing obviously works well enough to meet the main requirment of saving a dive trip when the electronics pack up.

Simon

22nd August 2007, 10:07	#5 (permalink)
SimonK Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Oct 2005 Location: Cumbria UK Posts: 231	Re: More qualitative testing results on Porter VCD1000 MCCR valve Some more thoughts on how this thing works. We have a laminar flow device with a built in regulator that controls the pressure drop across it to give constant volume flow. The input pressure is ambient plus the O2 reg IP. Assume the IP is 10 bar and the drop across the device is adjusted to 1 bar to give the desired surface flow rate. At the surface the input pressure will be ambient (1 bar) + IP (10 bar) = 11 bar. At 40m the input pressure will be ambient(5 bar) + IP(10 bar) = 15 bar. So the mass flow of oxygen will be 15/11 = 1.36 times the surface mass flow. Dodgy physics aside the thing obviously works well enough to meet the main requirment of saving a dive trip when the electronics pack up. Simon Last edited by SimonK : 22nd August 2007 at 14:15.
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