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> anthony,youre a smart man. Yes, he is. Very. > figure this out.solenoid failes on a closed > circuit,pumps a bunch of pure o2 into the mix,what happens? The user shuts the solenoid supply cutoff valve. If that took some time, the user switches to OC temporarily before the high PO2 makes its way around the breathing loop. The user flushes the loop with diluent, goes back to CC, and manually maintains O2 setpoint for the remainder of the dive. > at least in the > semi closed youre breathing a known gas mix before hand. Stop! Stop! You're killing me! Wait - let me catch my breath. Sorry, but the concepts of "breathing a known gas mix" and "semi closed rebreather" in the same sentence struck me as extremely funny. > now,back to closed > circuit,computer failes,whoops,we have no o2 readout. Any closed circuit rebreather that relies only on the computer to provide a PO2 readout has some serious design flaws. Fortunately, I know of no such closed circuit design that is or will soon be available commercially. Incidently, folks - my intention is not to be a "semi-closed basher". I really do think they have a place in diving, and depending on the particular unit, they can be damn useful in some situations. I'm just trying to stamp out buffoonery here. Aloja, Rich > - jt > > On Wed, 4 Sep 1996, Anthony Montgomery wrote: > > > On Wed, 4 Sep 1996, John Todd wrote: > > > > > rich,no one who takes one of those 4 day iantd/tdi/whatever agency > > > courses on "rebreather diving" will be trained right to deal with manually > > > controlling the functions of the rebreather that are normally controlled by > > > the computer.you of all people should realize that.on top of that,if the > > > computer cant be trusted then how can you expect to trust the electronic > > > output generated by the computer?at least with the mechanical rebreathers > > > (err, semi-closed) theres no fancy gadgetry or tomfoolery to mess with,and > > > as a result its safer. - jt > > > > > John, > > > > Do you really think semi-closed rebreathers are safer? It seems > > to me that diving on a unit which depends on expected workload and > > theoretical O2 consumption rate isn't safe. But actually I won't go as > > far to say that semi-closed systems are unsafe. I would consider these > > aspects of semi-closed systems a disadvantage just as I would consider > > the likelyhood of electronic failure a disadvantage for fully-closed > > systems. > > > > ANTHONY MONTGOMERY > > Marine Option Program Waikiki Aquarium > > 1000 Pope Road MSB #203 2777 Kalakaua Ave > > Honolulu, Hawaii 96822 Honolulu, Hawaii 96815 > > Fax: (808) 956-2417 Fax: (808) 923-1771 > > Phone: (808) 956-6000 Phone: (808) 923-9741 > > > > > > > > > > > > Richard Pyle deepreef@bi*.bi*.ha*.or* ******************************************************************* "WHATEVER happens to you when you willingly go underwater is COMPLETELY and ENTIRELY your own responsibility! If you cannot accept this responsibility, stay out of the water!" *******************************************************************
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