| Idea for mitigating solenoid-failure: open...
I was reading a thread on here about the Open Revolution and the discussion that was going around regarding whether to have one or two solenoids, or a stepper controlled needle valve, and I had a cunning (I think) idea.
Consider this - using YBOD as example:
O2 comes from depth un-compensated first stage, to KISS valve. Output hose from KISS valve goes to solenoid.
Under normal circumstances (within KISS principle depth limits) the KISS valve will feed O2 into and pressurise the hose that connects the valve to the solenoid to the point where the hose pressude balances the first-stage pressure - when the solenoid fires, this slug of gas feeds into the unit. Solenoid closes, process starts again.
If the solenoid ever fails open, instead of getting a huge flow of O2 into the loop like it would normally, once the slug has passed, the unit will just feed O2 like a normal KISS. Solenoid failure closed, can be managed using the manual injector as usual (for extra redundancy and depth potential, the manual buttin could be fed from an independant compensated first stage).
I guess this is basically just an elaboration of the idea used on the Boris and Mk15.x where tiny bore pipe is used to reduce the rate of O2 addition into the loop.
Thoughts, comments? |