Why no PST pro valve?

[noj3333]

I know PST tanks (at least some of them) need a 7/8 inch valve, but I was just curios why a pro valve has never been made in 7/8 inch? Lack of demand is the only reason I can think of, is there a technical reason that I'm unaware of?

 

[guruboy]

Aren't they usually 300bar?

 

[tursiops]

Aren't they usually 300bar?

Yes, it is a regulatory thing. Yokes can only be used to 3442, but not 3500+. So no need for a PRO/yoke valve for the 3500 PST.

 

[tbone1004]

I know PST tanks (at least some of them) need a 7/8 inch valve, but I was just curios why a pro valve has never been made in 7/8 inch? Lack of demand is the only reason I can think of, is there a technical reason that I'm unaware of?

because it's against the law since the tanks are rated at 3500. To get away from that, PST released the first 3442psi tanks with their E7 and E8 series in ~2003 ish? give or take a year or two, can't remember off the top of my head. You just don't see many of them because the company stopped producing scuba tanks 3-4 years later so there aren't that many around.
The e7/e8 tanks are standard 3/4" neck valves and I believe also came with the first "pro valves" or at least were released around the same time

 

[noj3333]

Thanks everyone... I didn't know they were 3500lbs tanks, I assumed all US HP tanks were 3442lbs.

 

[Bob DBF]

Yes, it is a regulatory thing. Yokes can only be used to 3442, but not 3500+. So no need for a PRO/yoke valve for the 3500 PST.

I believe yoke below 3500# since I have a Faber tank at 3498#, the plus rating for a 3180 service pressure tank. I do not believe it is illegal since it carries proper DOT certification stamps.

Modern yokes are made for 3500# service, and until the regulation there were manufacturers making 4000# service yokes. I have a 4000# service yoke reg Sherwood made over 35 years ago, it was an anomaly at the time.


Bob

 

[Lukas Ircha]

I believe yoke below 3500# since I have a Faber tank at 3498#, the plus rating for a 3180 service pressure tank. I do not believe it is illegal since it carries proper DOT certification stamps.

Modern yokes are made for 3500# service, and until the regulation there were manufacturers making 4000# service yokes. I have a 4000# service yoke reg Sherwood made over 35 years ago, it was an anomaly at the time.


Bob

I bought the yoke Mares prestige X15 first stage regulator set, 2 months ago. Would you assume that it is 3500psi or lower rated for? I am thinking of getting the DIN connection for it.

 

[tbone1004]

Yes, it is a regulatory thing. Yokes can only be used to 3442, but not 3500+. So no need for a PRO/yoke valve for the 3500 PST.

it's not a no need situation, it's a not allowed situation. DOT prohibits it regardless of whether the yoke was designed for higher pressures *i've seen some rated for 5000psi*. The skinny neck tanks were created specifically so the yoke valves which were the standard in the US using the 3/4" threads couldn't be used when rating for the higher pressure, and the 3442 tanks were created as a workaround to skirt the rule

@Lukas Ircha don't get caught up in the ratings, the working pressure and burst pressures are very different. With yoke you run a higher risk of o-ring extrusion when running at higher pressures. In this continent, you aren't going to see true 300 bar fills like you do in Europe, so it's a non issue aside from a regulatory aspect.

 

[Bob DBF]

I bought the yoke Mares prestige X15 first stage regulator set, 2 months ago. Would you assume that it is 3500psi or lower rated for? I am thinking of getting the DIN connection for it.

I would not worry about your yoke, but if DIN is your preference by all means change it. If you do go DIN, insure any dive ops you travel to has DIN valves available for you, and carry a DIN-yoke converter just in case.



Bob

 

[Paintballpsyco2369]

They most definitely DO exist. My doubles Are HP 100's and had a "pro valve" manifold when I first got them. I replaced it with a Thermo manifold once I finally tracked one down lol. Only time I ever used an insert was when I was transfilling with a scuba to paintball tank adapter... MAY have some pictures somewhere still of it if interested in checking it out...