All about H-valves and Y-valves

[LUBOLD8431]

NetDoc once bubbled...
You cannot buy a 200 bar DIN valve that fits a 300 bar tank. Consequently, my Hp S120s have a 300 bar DIN valve and I have two AL80s with the 200 bar convertible DIN valves.

Ummm.... you should really check your facts before you start stating things like this NetDoc.
The fact is, you can now. PST has started making all their tanks with a service pressure of 3442. They have also started making the old HP tanks (like your 120's) with a standard 3/4 " thread. What this means is that the line between LP and HP tanks has been blurred or completely taken away. You basically have either 7.25 inch diameter cylinders or 8 inch cylinders. Thats it. Pressure is the same now. And they come with a 200 bar valve. Not really a 300 bar cylinder (300 bar= 4350 psi), but definitely not 200 bar either (200 bar=2907 psi). Kinda weird Huh???

 

[The Chairman]

about this "new development"... hope to hear from them soonly :tease:

Well, since you are hell bent to prove me "wrong" once more... lets talk about those blurred lines. A 3300 psi steel tank is referred to as a 232 bar tank in Europe. A 3500 psi tank is 245 bar. 300 bar comes out to a whopping 4285 psi!!! It's a definite PIB! Still, my assertion was that you would not find a 200 bar valve to fit a 300 bar tank. I never mentioned a 232 or 242, and it's not my fault if the tank manufacturers use a sliding scale and keep changing things.

However, please look at this URL...

http://www.thermovalves.com/stand_alone_series.htm

and

http://www.luxfercylinders.com/products/scuba/specifications/us_imperial.shtml

From these URLs, it appears that above 232 bar, the manufacturers go to a 7/8"x14 UNF thread instead of the 3/4"x14 straight pipe thread. I would be interested to see a 200 bar DIN valve with the 7/8"x14 UNF threads, but I don't think they make it. Will this change? Sure. But that's not my decision or fault.

And really, if you just want to catch me being "wrong"... you don't have to go through that much trouble. But really, it's not about WHO is wrong, but WHAT is right. I am not defending any position as much as I am stating the facts as I know them. I will be glad to change my perception of reality with just a bit of proof. Only a fool thinks he has it all figured out. And I don't see him on the board much these days... :tease:

 

[The Chairman]

Pressed Steel Tank Company currently does not make a 300 bar service pressure cylinder for scuba use. Our 240 bar (3500 psi) has a 7/8-14 thread. The new E-Series with a service pressure of 3442 psi (230 bar) has a 3/4-14 and so did the discontinued LP-series. Spec sheet attached.

Best regards,

T.Ivey
Scuba Product Manager
E-mail: tivey@pressedsteel.com
Webstscuba.com

But wait... there's more. It shows the HP120 being renamed to being an E7-120 with a service pressure of 3442 psi and not 3500. It is also showing the LP-104s being changed to an E8-130 with the same service pressure. It also indicates that the tanks will ship with a factory installed "DIN/K valve".

 

[LUBOLD8431]

YEs I know....

 

[globaldiver]

I am planning to purchase a single PST E8-130 when it is available. Does anyone know a really good H-valve that would fit the tank?

Sincerely

Anders

 

[Scubaroo]

Thermo, Sea Elite and Dive Rite all make very similar H valves that would fit that tank.

 

[globaldiver]

How are the OMS H-valves in comparison?

Anders

 

[KilgoreTrout]

I can't tell you which valve is better, but I can tell you that the major difference is that the OMS has an o-ring face seal type of connection. This would be similar to a yoke regulator on a tank.

Dive Rite, Thermo, Halcyon, Sea Elite all have double barrel o-ring seals. Only one o-ring would be required to make the seal, but there are two. This at least partial provides redundancy.

This is the major difference and was the point that caused me to go with anything other than OMS. It also helped that OMS was more expensive than some o' the others.

Hope this helps. Maybe someone that has torn both types down could shed more light on the subject.

Good Day.

 

[LUBOLD8431]

Well, Dive Rite is a good option, but you will only be able to get the 200 bar version, not 300 bar. They discontinued the 300 bar version.

Thermo valves can be ordered right from PST. Why not just order the cylinder with the H valve from Thermo???

Thermo is a good valve, basic configuration, and all the PST cylinders come with them. I have had some trouble with older style Thermo, but not the new ones from the last three or four years...

Good Luck.,..

 

[globaldiver]

Thanks for all the great info.

Sincerely

Anders