As far as I can figure out from the web and the 1962 diver's manual loaned to me by my local dive shop, they were J-valve-like, but instead of any moving parts, they simply had a restriction that choked off the air at a low pressure so breathing became hard.
But then things seem to diverge...
Some places say you could reach back to the knob, turn it and get the rest of your air like a J valve, others imply that you just had to ascend, and as the air viscosity dropped with ambient pressure, you could breathe on the way up.
Anyone have any experience with this kind of valve, and if so tell me about it!
Roak
But then things seem to diverge...
Some places say you could reach back to the knob, turn it and get the rest of your air like a J valve, others imply that you just had to ascend, and as the air viscosity dropped with ambient pressure, you could breathe on the way up.
Anyone have any experience with this kind of valve, and if so tell me about it!
Roak