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Vintage Scuba: The King of Tank Valves

King of scuba tank valves

Hey, folks, Alec Peirce with Vintage Scuba and you are looking at the king of valves. It doesn’t have a crown but has everything else. This is it: the ultimate valve.

Valves today are on/off valves and are as common as kitchen taps. Valve development over the years changed a great deal from the old-fashioned pillar valves that would freeze up and break, until what we have today. In the meantime, there were a lot of pretty unique valves made. Let me tell you about it.

This one I’ve chosen is one simple valve that I’ll call the ultimate! The number one! The king of valves! Whatever you want to call it. I like this valve. First of all, it’s heavy and weighs about four pounds. It’s solid brass, chrome-plated, and beautifully made by a big brand name company, SCUBAPRO®. This is a modern valve you can use in your tank if you want to. It’s a three-quarter inch o-ring seal used in any steel, old steel, 72-cubic-foot tank or aluminum tank, and many of the new steel tanks so long as you use a three-quarter inch.

So why do I call it the king of valves? First, it’s not just the fact it’s made by SCUBAPRO®, which implies, quite rightly so, extremely high quality and great performance; and it has wonderful features. This valve in particular had one of the finest operating mechanisms made. Turning this knob does not directly control the air flow: there is a separate threaded seat in the valve, which is what turns the air on and off. It takes a fair bit of effort to move that seat, and this knob has a spindle or fork on it that fits into that threaded high-pressure seat. Turn this and you turn the fork: it’s quite easy to turn this; the fork is sealed with an o-ring seal and is quite easy to turn. As you turn it in and out, it moves the threaded seat in and out. It’s easy and doesn’t get open or jammed close; it does a very effective job at opening and closing the valve.

Performance is one thing it does a great job at. Secondly, this valve has a “J” mechanism, a reserve mechanism, on it. This is a spring-loaded reserve mechanism, as was very common during the ‘50s and ‘60s, and into the ‘70s. Many divers wanted to have the “J” valve, and at one time it was mandatory. When I started diving in the late ‘50s and early ‘60s, we didn’t have pressure gauges or computers or any mechanisms that would tell us how much air we had in the tank when we went into the water. We measured the air when we went in to be sure the tank was full, and would guestimate based on experience and a little bit of rough math, how long that tank would last us. We were pretty good, but it was quite common for us to miscalculate or run out of air. This reserve mechanism, when you ran out of air, allowed you to reach back and pull this down, which gave you a few extra minutes of air: 300 psi to be exact, which could be one minute to five minutes depending on your depth.

J-rod groove

What else did it have? I mentioned we did not have pressure gauges underwater so there was no way of knowing how much air you had in your tank: you had to have a separate pressure gauge on a yoke: it wasn’t water-proof and you would check the tank before or after the dive. Let’s take a look at the back of this valve.

There’s a mechanism on the left hand side – the J rod side – with a groove and a rod in there. If you look carefully at the side of the groove, you’ll see “E” at the bottom for empty, “1/2” halfway up, and “F” for full. It’s very simple. When this valve was inserted into the tank, there’s the standard spigot that prevents water or debris from going into the valve and regulator. On that bottom part there’s a little hole: high pressure air from the tank would also go through that hole, which is directly below the pin. When you filled your tank at the dive store, with this valve in it, the little pin was pushed to the top, “F”. You would say, “Oh. I have my tanks full.” As you started to breathe, removed air from the tank, the pressure would drop and that pin would slowly go down to eventually empty. There’s a built-in pressure gauge. How practical is it? Not very. If you didn’t have one of those 10-dollar surface pressure checkers, this might be valuable because before the dive you could take a look and say, “Ok. My tank’s full! Let’s go, guys!”

All in all, this was a fantastic valve. It was easy to operate, solidly built, with a reserve mechanism and pressure gauge. It’s a wonderful valve, and that’s why I call it the king.

That’s it. King of valves. Talk to you soon. Alec Peirce with Vintage Scuba.