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It still sucks. Jim On 5/2/98 1:59 PM Jan M. Troup wrote: >Dear Divers: > >I just was made aware of this mail list and would like to respond to some >of the questions/comments that have been made. First of all, the X-tra >System is intended for the recreational diver who would like to have a pony >bottle backup system. Diving test and the calculations show that 6 cu ft. >is only enough air for a safe assent from about 100 ft. 13 cu ft. (which is >offered along with 19 and 30 cu ft cylinders) would address deeper diving >situations or specialty dives. The X-tra system can be used like any other >pony bottle if desired with the main advantage in this case being an easy >filling system and a low profile combination valve/1st stage regulator. In >this situation, two Scubapro high pressure disconnects are used on each end >of the fill line and the X-tra system is detached from the main system. >This is how I expect the larger cylinders (19 and 30 cu ft) two be used for >cave divers and other specialty divers. > >The standard (recreational) application for X-tra is to leave the high >pressure transfer line hooked up all of the time. This has many advantages >and one potential disadvantage. If any thing happens with a diver's primary >system or any of the high pressure lines, X-tra is isolated and supplies a >bailout supply. The transfer line insures that X-tra is topped off on >repetitive dives and provides that the entire air supply is available in the >event another diver needs your safe second. By attaching X-tra to the power >inflator, the diver knows that the pony bottle regulator is always working >(auto-checking) and air is available. No more pony bottles that have leaked >down >or had a regulator full of sand without the diver knowing. > >The bad part of having a transfer line is that if something happens to cause >X-tra to free flow or leak, then the total air supply could be >lost. During recreational diving situations, a diver is likely to notice an >unstoppable massive leak or a free flow and should start an ascent >immediately. The good news is that no matter what happens with the X-tra >system the >maximum air loss rate is the same as the fill rate of about 6 cu ft. per >minute or about 250 psi of an 80 cu ft. cylinder per minute, and most divers >could deal with this situation by making a controlled ascent. > >The X-tra system can give redundancy without complexity. If a diver uses an >Air2 or other combination safe second/power inflator then the redundant >system has only one hose into the pony bottle and one hose out. Only one low >pressure hose (to possibly fail) out side of the backup system. > >To answer the serious technical questions: >1. Aquavit, Inc. makes the first stage regulator that includes the check >valve and PIN pressure gage. The regulator is a piston type with depth >intermediate pressure adjustment and is very much like a Scubapro MK2. The >intermediate pressure can be adjusted with shims to give about 125-145psi as >desired. I prefer about 130psi to avoid free flows. Service kits are >available and X-tra can be serviced by anyone experienced in normal >regulator maintenance. All X-tra units are pressure and leak tested and >adjusted for intermediate pressure. > >Jan Troup, President >Aquavit, Inc. >email: aquavit@aq*.co* > > > > >-- >Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. >Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. > ------------------------------------------------------------------- Learn About Trimix At http://www.cisatlantic.com/trimix/trimix.html -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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