best apeks for cave (routing)

[dbg40]

What does capturing on O-rign mean? If your O-ring splits in a DIN or K-valuve, isn't that the end of your gas supply from that cylinder no matter what. Has anyone ever experienced "capture of an O-ring" and how did DIN help?

When an O ring pops it is open to blow out of the fitting as soon as it clears the small lip that holds it in place. In a DIN the O ring is burried in a solid wall, or tunnel. And has no escape for a weakened O ring to go. Even if it does go, the fitting, by nature slows the loss of gas. I have never blown an O ring on a din reg.

 

[merkin]

I'm really not trying to give you a hard time (and am leaning towards DIN regs anyway), but everyone seems to parrot this line, but no one has experienced it (both ways). I'm not intuitively seeing a significant hindrance to air escaping the cylinder with a "captured" O-ring. All I picture the difference to be is that after the dive you still have the torn up O-ring to show your dive buddies and thank your stars you made it. In the extreme case of "capturing", there seems to be no need for an O-ring at all in normal functioning of the first stage. Have they ever set up tests on how much longer a cylinder with a blown O-ring lasts when it has DIN vs K valve? Given the explainations I have been given I'm thinking that maybe it prolongs air for another minute but that is of marginal benefit 1000' back in a cave where your cylinder is shooting high pressure bubbles at the ceiling....Probably better to just turn the damn thing off quickly to preserve vis and air shar out of there.

Please forgive me if I offend anyone, just trying to think through this fully given my extremely limited knowledge and experience.

 

[dbg40]

I can't say that there has been such a study, the actual diference is in the construction fo the valve itself. It holds the O ring in such a way that it is far more dificult for the O ring to fail in the first place. Aside from O rings, there are other advantages as well. There are fiewer points of capture, on A DIN valve as opposed to a yolk, and It is a much stronger connection as well. There is a reason that HP tanks will need to use the DIN and not a yolk connection. The Yolk will not support the higher pressure. It's not really a question of opinion, it's engineering, they are dsigned to work at higher pressures and not fail. Im not trying to sway your opinion in any particular direction, only that there are intrinsic advantages in one type over the other. Ultimately, for lower pressure tanks, the decision is yours, but I use Din because it allows me a margin of safety that is higher than that of yolks, and allows me to switch off easily if needed. All you have to do is look at the older pre E7 tanks from PST, to see that the valve will NOT accept a yolk fitting at all. Reasons of component failure. Somthing that I really don't wish to deal with if I don't have to. You decide.