"Johnny Christensen" <Johnny_chri@hotmail.com> skrev i en meddelelse
news:422def54$0$29279$14726298@news.sunsite.dk...
> Det kommer an på flaskens alder og nationalitet. 3/4 var engang
> standarten.
> Men de sidste 10-15 år er det M25 der er anvendt på det europæiske marked.
> 3/4 bruges fortsat i USA (de er lidt tilbagestående
En lille advarsel er her på sin plads!!!
En M25 ventil kan godt skrues ned i en 3/4 flaske, men ikke omvendt. Den
sidder lidt løst i flasken indtil man strammer den op mod O-ringen,
hvorefter alt synes ok.
Problemet er bare at gevindet ikke går ordentlig i indgreb, så man risikerer
at ventilen skydes ud af flasken under fyldning, med alvorlig fare for de
mennesker der måtte være i nærheden.
Søger du lidt på nettet kan du sikkert finde historier om folk der er kommet
galt af sted. Du skal altså være 100% sikker på at falsken har M25 gevind
før du monterer en M25 ventil.
Her er en historie jeg fandt på google:
> >Are you referring to Gene Broome's accident at Branford Dive Center?
> >
> >That was the result of someone putting a metric threaded valve into a
> >standard tank. As it turns out, the thread pitch and shank size on an
> >M25 valve is very close to that of a 3/4" NPG valve - close enough,
> >in fact, that the valve can be screwed right into a standard US SCUBA
> >cylinder. The thread depth and radiusing are different enough,
> >however, that the metric valve will not "hold" as well as a proper
> >valve would.
> >
> >What happened was that Gene was filling the tank, and the valve flew
> >out when the pressure reached about 1800 PSI. The force threw Gene
> >across the dive shop, and he was hospitalized for some time with some
> >pretty serious injuries (thankfully, no lost limbs). The tank did NOT
> >"blow up", however, and I am not aware of any widespread problems
> >with the necks of STEEL tanks (aluminum tanks, of course, are another
> >story entirely).