Great history lesson with the J-valves and tapered threads, real Cousteau stuff! Here in UK/Europe A-Clamp valves are certified up to 232Bar (3365psi in old money) and but hardly anyone uses them; DIN is almost universal. The 200 or 207 Bar max only applies to Aluminum tanks but that's sort of viewed here as 'low pressure'. Our tanks have to be stamped with 'breathing gas' or something similar, as well as all the inspection and cert data, but I think anything that didn't have a DIN scuba valve would instantly spark a question.
Hello @timgosling6189, thanks for sharing. Here in the States, we must either have a DOT or CTC stamp which is regulated by the United States Department of Transportation. Our hydro stamp must be with in the last 5 years of the date of use, and the visual sticker must be displayed and with in the last year of service. Its always a shocker to our customers and clients when we take them out of the country and they see things done differently.
@@LakeHickoryScuba Same here. It is fun when you get a tank from the dive shop in some remote place and can't even read what's on it, let alone if it's in date!
Thank you for good info. The threads you mentioned are usen in America. In Europe the neck threads for scuba is mainly M25x2. Also in some small tanks (e.g. some dry suit gas bottles) M18 is used. Some older tanks have tapered threads.
So i guess the answer to the title question is ... "The cylinder is threaded to accept the type of valve commonly used in the scuba insustry" I came into posession of a small cylinder maybee 4-6 cu ft. that had a calibration gas used to adjust a medical instrument. I was trying to figure out what I could use it for but I have no idea as to the thread type of the cylinder so it just sits in a corner of my closet. I have bought and sold several used tanks I recenly got burned when the hydrotest facility failed one of them erroniously on the visual (using the pit depth gauge improperly) and LOST another one, the third one in the bach of four failed honestly with bad threads. So in the end I had the same amount of money in one used tank as I would have just buying a new one. Win some lose some.
