Are PST tanks top of the line?

[MXGratefulDiver]

Well, what I was told was that it isn't a problem for the tank/valve, and not a problem in the short-term for the reg, but using a yoke reg (which are usually only recommended for 3000 pounds) on the tanks filled to 3400 over a long time can put unnecssary pressure on the regs. The tech at my LDS said that he can see a difference in the amount of wear on the regs he service that use these tanks with a yoke connector.

The type of tank adapter on your reg has nothing to do with the amount of wear on the first stage. Your tech is feeding you erroneous information.

The difference in DIN or yoke adapter boils down to how the o-ring that creates the seal between cylinder and regulator works. A DIN type regulator screws down onto the o-ring, effectively "capturing" it between two metal surfaces. A yoke adapter relies on the air pressure coming from the cylinder to push the o-ring up against the surface of the regulator to create the seal.

In the latter (yoke) style, a decent sized scratch or dent on the sealing surface can be enough to cause leakage ... or cause the o-ring to become deformed (resulting the familiar blown o-ring). There is less of a chance of this happening on a DIN reg because of the way the o-ring gets captured when the screw-on part of the regulator is tightened.

For higher pressures, the DIN regulator is recommended because of the difference in how the o-ring gets captured ... the internal portions of the first stage are identical, regardless of whether it's a yoke or DIN style reg.

... Bob (Grateful Diver)

 

[Al Mialkovsky]

Seems the topic has been well covered. I recently went to PSI steel 120's, hp. When I did a live aboard they only filled to 3000 which still gave me over 100 cubic feet.

I'm an old overweight man who now dives with 12 pounds wearing full rubber. Ya gotta love that.

 

[drbill]

Bob- Your response to SAF_25 doesn't seem correct in terms of her statement. If the reg's yoke-style first stage is rated at 3000 psi, it is possible that attaching it to a HP tank might cause problems over time. Of course if the yoke reg is rated for higher pressures, it should be no problem. Therefore it is the pressure rating of the reg that is the issue rather than it being yoke or DIN.

I use Mk10/G250's in both yoke and DIN configuration. The yoke reg (rated at 3000 psi) is attached to my 3000 psi pony bottle, the DIN reg to my HP tanks.

Your information itself does seem correct, but not with respect to the specific issue saf_25 raised.

Doc

 

[MXGratefulDiver]

Bob- Your response to SAF_25 doesn't seem correct in terms of her statement. If the reg's yoke-style first stage is rated at 3000 psi, it is possible that attaching it to a HP tank might cause problems over time. Of course if the yoke reg is rated for higher pressures, it should be no problem. Therefore it is the pressure rating of the reg that is the issue rather than it being yoke or DIN.

I use Mk10/G250's in both yoke and DIN configuration. The yoke reg (rated at 3000 psi) is attached to my 3000 psi pony bottle, the DIN reg to my HP tanks.

Your information itself does seem correct, but not with respect to the specific issue saf_25 raised.

Doc

I am addressing this statement in particular ...

The tech at my LDS said that he can see a difference in the amount of wear on the regs he service that use these tanks with a yoke connector.

The type of connector - whether DIN or yoke - has nothing to do with what's going on inside the first stage. They don't make separate first stages based on the connector type.

If you purchase a regulator with a yoke connector and the same type of regulator with a DIN connector, they come with EXACTLY the same first stage ... and all the parts you use to service them are exactly the same.

Therefore it makes no sense to tell someone that there is more wear on one than on the other, based on connector type.

Now, it might be more accurate to tell someone that using HP cylinders will create more wear over time than using LP cylinders ... but that will be independent of the type of connector you are using.

The pressure rating on your regulator is relevent to the connector type, not to the first stage itself. The tech is confusing two related, but separate, parts of the air delivery system.

If you take two same-make (say, for example, ScubaPro MK16) regulators - one with a DIN connector and one with a yoke connector - and use them on the same tanks over the course of a year, you should notice the exact same amount of wear on both of them.

... Bob (Grateful Diver)

 

[OneBrightGator]

I've been writing to write that exact post, I agree with ya Bob.

Ben

 

[FengShui]

I think both Bill and Bob are right. The only difference between a reg with a yoke connector and a reg with a din connector on it is the connector. They are identical inside the reg. However, Bill is right that you might see more wear on the yoke itself if you were consistently using a yoke with tanks in excess of 3000 psi. Also, Bill would be right if there were such a thing as a reg that was only available as a yoke and that couldn't take a DIN connector. However, I've never heard of such a reg. In general, if you're going to use a reg at high pressures, I'd recommend a DIN regulator. They're safer, and they easily convert to yoke when you're on vacation or are away from your regular tanks.

 

[drbill]

I always dive DIN except when I travel (and on my pony). However, it was my understanding that some regs are rated at 3000 psi and others at higher pressures. I may not be correct on that (I'm a marine biologist rather than an equipment tech). In fact I had thought that the Mk10/G250 yoke rig I use on my pony was rated at the lower pressure. If that is simply a matter of the yoke fitting, great!

Doc