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> 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. Sorry, I feel that the "X-tra" complication added by the nonconventional valve and 1st stage don't add anything. Any reasonably competent diver who uses a pony bottle as a bailout gas supply knows how to fill it and keep it filled. A transfer whip is easily obtained and doesn't go along on the dive to provide additional opportunities for life support equipment failure. > Diving test and the calculations show that 6 cu ft. > is only enough air for a safe assent from about 100 ft. Not the main point of this discussion, which is the Rube Goldberg hardware, but 6 cf is not sufficient in a real emergency. A safe ascent from 100 feet allowing for stress, which usually accompanies an emergency situation such as loss of main gas supply, will likely require more than 6 cubic feet of bailout gas. And don't forget the precautionary decompression stop. > 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. Not an advantage over conventional K-valve and real regulator which can be used with other cylinders. > 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. I see you've done absolutely NO market research. What cave diver told you that cave divers use pony bottles? > 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. Again, this addresses a non-existant problem, and adds failure points and forces the diver to carry one more piece of non-interchangeable equipment. > 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* Jan, with all due respect, your product is worthless. Whatever price you're asking is too high, and the money is better spent on a conventional pony bottle, a real regulator, and training in how to use and maintain it. Art Greenberg artg@ec*.ne* -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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