J Valve

[vjb.knife]

John I noticed that your first and third picture show a Scubapro J-Valve. If you look at the third picture it shows the slotted valve adjustment which changes the reserve pressure of the J-Valve, when you push in and turn 90 degrees the inner slotted stem. Nice old triple set also. When I was in Commercial Diving school they had a Quad set of steel 72's, it was kind of set up as a joke, but it was diveable, if you had the stones.

 

[John C. Ratliff]

John I noticed that your first and third picture show a Scubapro J-Valve. If you look at the third picture it shows the slotted valve adjustment which changes the reserve pressure of the J-Valve, when you push in and turn 90 degrees the inner slotted stem. Nice old triple set also. When I was in Commercial Diving school they had a Quad set of steel 72's, it was kind of set up as a joke, but it was diveable, if you had the stones.

I'd love to dive those quads, but they would have to get them into the water, and out again, before I entered.

SeaRat

 

[JamesBon92007]

I'd love to dive those quads, but they would have to get them into the water, and out again, before I entered.

SeaRat

Those quads must be the reason someone invented the back wing in the first place.

 

[captain]

John I noticed that your first and third picture show a Scubapro J-Valve. If you look at the third picture it shows the slotted valve adjustment which changes the reserve pressure of the J-Valve, when you push in and turn 90 degrees the inner slotted stem. Nice old triple set also. When I was in Commercial Diving school they had a Quad set of steel 72's, it was kind of set up as a joke, but it was diveable, if you had the stones.

US Divers commercial division sold a triple 72 set up in a triangular pattern using bar yokes and two sets of double bands to link them together. I think they were used as bail out cylinders for deep surface supplied dives.

 

[vjb.knife]

Those quads must be the reason someone invented the back wing in the first place.

That was way before the use of wings, we were diving horsecollars at that time.

 

[vjb.knife]

US Divers commercial division sold a triple 72 set up in a triangular pattern using bar yokes and two sets of double bands to link them together. I think they were used as bail out cylinders for deep surface supplied dives.

I have seen that configuration but I have never seen it in use commercially. On PTC / Bell and Saturation dives we were either going without bailouts or just a single tank

 

[JamesBon92007]

That was way before the use of wings, we were diving horsecollars at that time.

With four 72s I'm thinking you probably had no weight belt and were still negative. No?

 

[John C. Ratliff]

James,

No, not true. The twin 72s in seawater were almost neutral, especially toward the end of the dive. They were well-thought-out dive cylinders, and not the hellaciously heavy steel cylinders of today. They universally had a J-valve in the manifold too. So four 72s would not be a great burden in the water (but getting out with them on would be a problem, even when I was young).

Now, about the using the J-reserve valve on different tank sets. I don't particularly like them on a single tank when I'm monitoring a SPG or dive computer, as the pressure will vary as I breathe. The variation has to do with the decrease in the HP coming into the regulator from the J-valve. You will see the needle drop and come back as you breathe. It is distracting.

But if you use a J-valve on a twins manifold, there is no needle drop. That is because only one cylinder has the air restricted. So what I have done is to use my SPG/Dive Computer in conjunction with the J-valve, and use the J-valve in the up position. I dive the scuba without using the J-valve, and it's there if I should need it. It is like having a bailout bottle, but more streamlined.

SeaRat

 

[SurfLung]

I have J-Valves on all of my single and twin tanks. Sometimes I use them with an SPG but most of the time I keep it simple and dive with just my regulator and J-Valve and watch. The watch tells me when I'm a little less than halfway through a dive and its time to turn around and come home. Usually I get home before I run out of air, so I'll play around for awhile so I can run out and use the J-Valve.

This thread started out talking about how expensive the XS Scuba J-Valves are. I want to mention that there are still PLENTY of USD reserve valves around. I bought a few last year that are in like new condition... Paid only $35.

John Ratliff sold me on J-Valves as essentially a Spare Air that you don't have to carry around separately. In that sense the reserve is downright elegant by comparison.The reserve air doesn't last long down deep. But it's plenty to get you to the surface. All of my deep dives start deep and end shallow so if I hit the reserve, its usually plenty enough air for a safety stop as well.

And finally, I was going to suggest "Free Ascent" as a tongue-in-cheek "skill" that a J-Valve diver should have. These days, so many divers have never actually run out of air to know what it feels like. When I was in High School we dove until we ran out of air and then we came up. So running out of air wasn't a terrifying emergency... It was just... Time to come up. Of course we weren't diving 100 feet down... But coming up empty from 15-20 feet was fairly common.

 

[2airishuman]

Thanks for the responses...ok now....how many of you still dive with a J valve on your tank?

I have a J regulator that I sometimes use.

J tank valves tend to leak down in a few weeks after a fill because the J valve is always pressurized. Parts availability is a problem and over the years the valve stems get corroded or scored. With a J regulator it doesn't matter.