3000psi on 1st stage, 3442 on steel tank. Is this gonna work?

[jhelmuth]

Huh, could you please let me know what these mods are? Because as a service technician, I would really like to know what kinds of mods you are making to HP seats and/or orings to make them deal with HP better. AS far as I know, there are no such things. Certain manufacturers have changed their seat material over the years to make it more reliable when using HP.
I just dont know what you may be referring to...

I am told that higher durometer ratings are used to account for higher pressures. Makes sense to me. I'm not making the mods, so I do not know. Apparantly (deducing from your comments), there are reg techs that make claims that are just not so. Can you give me some confidence that this is bunk and that it's not just something that you have not learned (I'd grant that this is not a maufactures suggestion - so I don't suspect that it's a training issue). Durometer on o-rings serve to account for the required higher pressures to distort the oring to seal, but not to the point where the o-ring "blows" (and it's wearablity). Would you agree or disagree with that statement?

 

[LUBOLD8431]

All manufacturer's service guidelines that I know of require that you use a manufacturer's service kit to overhaul that reg. There aren't two different sets, one for LP and one for HP. Most manufacturers have made revisions to the designs and to the service kits over the years because of higher pressure cylinders, but I have not heard of any mod to be made by a tech because of HP (Leaving Scubapro out of that generalized statement, because I am not too familiar with them).

Some oring durometers are higher than others because the material is not as resistant to chafing or damage. IE, viton orings may be 90 duro where as in the SAME situation, a EPDM (or EPR) oring may only need to be 70 duro. It depends on the composition of the oring to determine the hardness (durometer) suited for a particular application.

 

[alemaozinho]

I've a new Aqualung Legend Regulator. On my 1st stage it is stamped 3000 psi. I'm planning on purchasing a HP steel tank. The psi is 3442, will this harm my 1st Stage? Thanks for any help!

you have to have a DIN connection on your first stage reg if you use high pr,steels peace

 

[Dryglove]

you have to have a DIN connection on your first stage reg if you use high pr,steels peace

The PST E series tanks are not considered a 300bar DIN high pressure(3442psi)tank and come with a 200bar valve with a threaded yoke insert letting you utilize either a DIN or a yoke equipped first stage as long as your yoke is rated to the specified pressure of the tank(3442psi).

 

[jhelmuth]

All manufacturer's service guidelines that I know of require that you use a manufacturer's service kit to overhaul that reg. There aren't two different sets, one for LP and one for HP. Most manufacturers have made revisions to the designs and to the service kits over the years because of higher pressure cylinders, but I have not heard of any mod to be made by a tech because of HP (Leaving Scubapro out of that generalized statement, because I am not too familiar with them).

Some oring durometers are higher than others because the material is not as resistant to chafing or damage. IE, viton orings may be 90 duro where as in the SAME situation, a EPDM (or EPR) oring may only need to be 70 duro. It depends on the composition of the oring to determine the hardness (durometer) suited for a particular application.

OK. I found some evidence to support your claim a bit more (hey - it's grewat to challenge a notion with me cause it makes me go off and do some reasearch)...

"The only difference between the two DIN designs is that a male 5-thread DIN regulator fitting is not long enough to mate properly with a female 7-thread DIN valve fitting, preventing the accidental connection of a high-pressure cylinder to an older regulator not intended for high-pressure. However, a regulator with a male 7-thread fitting will mate just fine with a female 5-thread DIN valve. Any first stage regulator DIN fitting can be attached to a K-valve using an adapter that attaches to the regulator. The first stage regulator yoke fitting can be attached to a 5-thread DIN valve using an adapter insert that screws into the valve"

So I would deduce that this is strictly a function of thread count (since the designs are identical otherwise). Still, I don't think there is much danger in the yoke designs at 3442 PSI. I am told that DOT ratings (in general) require a multiplier (IE - a rating of R requires that the actaul failure is 3xR, or some multiple). I beleive that FredT posted something like or about this).

I agree that there are not LP and HP "kits". I stated that in my earlier reply. Again, I do think it's reasonable to state that a slighlty higher durometer o-ring would be more appropraite choice in a higher pressure application due to the way o-rings work. If you change material composition, then I'd have to agree that the duro may not be the same. But that's relative to the change in material. If you keep the material constant, then I still would say that I've made a correct statemernt on the relationship of pressure to duromenter rating.

 

[jhelmuth]

I stand corrected on the yoke rattings (see below - I think this is actually typical as I've see 200-232 bar). I'll disagree anyway (but I'd like to see the facts on it being about the "strength" of the yoke). It's what I was taught and the emperical evidence would seem to support it. I say it's the blow-out pressure of the o-ring that is more relevant. I don't beleive that 3500 PSI will cause a yoke to fail. I've see it too much and have never seen or heard of such a failure at that pressure.

PS - I've gotten this from Oceanic reg mannual:

WARNING: Maximum working pressure for an Oceanic yoke style connector is 3500 PSI (232 Bar) and for a DIN style connector is 4500 PSI (300 Bar).

Update: Scubapro (that what I use) is also rated to a Maximum working pressure of 232 Bar (even though its yoke is stamped and designated as a 200 Bar connection)!

So maybe the Maximum working pressure for all 200 Bar yokes is ~ 3500 PSI (232 Bar)?
I'll continue to look at other more popular vendors and see what they say...

 

[jhelmuth]

Update: Scubapro (that what I use) is also rated to a Maximum working pressure of 232 Bar (even though its yoke is stamped and designated as a 200 Bar connection)!

So maybe the Maximum working pressure for all 200 Bar yokes is ~ 3500 PSI (232 Bar)?
I'll continue to look at other more popular vendors and see what they say...

Mares yoke Max working pressure is also 232 Bar (3500 PSI).

 

[jhelmuth]

The PST E series tanks are not considered a 300bar DIN high pressure(3442psi)tank and come with a 200bar valve with a threaded yoke insert letting you utilize either a DIN or a yoke equipped first stage as long as your yoke is rated to the specified pressure of the tank(3442psi).

FYI...

200 Bar valve = ~ 3000 PSI (actually 2900 PSI)
232 Bar valve = ~ 3500 PSI (actually 3364 PSI)
300 Bar valve = ~ 4500 PSI (actually 4350 PSI)

 

[Dryglove]

My mistake that should be 232bar tank valve in place of 200bar that i typed. For some reason i was thinking it was 200bar.

FYI...

200 Bar valve = ~ 3000 PSI (actually 2900 PSI)
232 Bar valve = ~ 3500 PSI (actually 3364 PSI)
300 Bar valve = ~ 4500 PSI (actually 4350 PSI)

 

[jhelmuth]

No problem. I wan't pointing out a mistake. Just posting relevant info...