repairing an I valve

[shackle]

???Does anyone have any experience working on I valves? I don't know the name of the part, but the "retention nut?" on top of the valve nob actually broke loose. Any input would be appreciated.

[SeaRat]

I'm assuming that you are talking about an old, 1/2 inch K-valve. It looks like an "I" on the tank, so that may be where you are getting that name. But there really is no "I" valve for diving that I am aware of. Does it look like this:

Figure 3-94 is from Fred Robert's book, Basic Scuba, Second Edition[/B],D. Van Nostrand Company, Inc., Princeton, New Jersey, 1963, page 285. This book is a "must have" for anyone working on old regulators and valves.

If so, it has probably suffered a broken stem. These are not too easy to find now, and are probably unique to each manufacturer's valve (US Divers, Healthways, etc.). So we really need a lot more info to give you an idea of whether it can be fixed or not. Dan may have some old parts laying around for a 1/2 inch K-valve.

John

[Deleted]

John is correct........unless you can find a motherlode of k parts, you wil have to GI it and machine your own......tedious work at best...........

good luck........

Mossback

[shackle]

Yes, that is the type of valve. I had heard them referred to as " "I "valves somewhere. It is a Healthways and was on my 38's. I kind of figured it was toast and knew you guys would know for sure. So, I guess I need to start shopping. I appreciate the input gentlemen.

[Captain]

What number part is broken in the diagram.

[SeaRat]

Shackle,

Do tell us the part. A lot of us may have one or two of those valve laying around. I have two of these valves in the tool box, but they are USD.

John

[shackle]

Thanks. I am away from home, but will be back tomorrow evening. I'll take a closer look and see exactly what I might need and let you know. Thanks again.

[duckbill]

I'm curious. My similar Healthways post-type K-valves have domed "cap plugs" as shown in the illustration, but I've never seen one on a USD valve. Has anyone here seen the USD valve with a domed cap nut/plug as illustrated?

[SeaRat]

Well, Shackle and Duckbill aren't going to believe this, but because of Duckbill's question, I went out to look at my two 1/2 inch K valves. I came in shaking my head. Now, because I've gotten to the age when I can tell stories twice (this one in buried somewhere else on this site), I'll tell you how I came to have two Healthways 1/2 inch K valves.

When I was still in the US Air Force, I was given two 20 man life raft bottles by a guy in the life support section. They could not re-use them, but they could give them to us. Well, in Pararescue we used these bottles as our jump tanks. I was the one in charge of them in some of our squadrons, so I knew how it was done. They were wrapped with piano wire, so I proceeded to unwrap them, then had their necks tapped for 1/2 inch valves. I still had some USAF bands for these tanks, and so used these with a military harness, but I did not have a double manifold (these were getting rare, even in the 1970s, as the companies were switching to 3/4 inch valves). So I bought two 1/2 inch valves, and connected them with a double yolk, to use as my doubles (see the photo of me and those doubles, with the K valves, yolk and a Trieste II regulator in Clear Lake, Oregon, circa ~1975; photo by Bruce Higgins).



I used them for over 10 years, until I heard that the USAF was condemning these tanks because of thread problems from the tapping. I looked at mine, and sure enough had a few cracks in the threads. They were stamped to ICC specs, with a 2100 psi rating, were probably about 42 cubic foot tanks, and had passed several hydros. I had the LDS drill them anyway (that's right, drill a hole in each of them) so they could never again be refilled. I have missed them ever since.

Then this thread came along, and I was sure that these were USD valves. But Duckbill asked about that "cap plug" so I had to look because I remembered this cap plug on my valves. Sure enough, they state on the side of each valve,

"HEALTHWAYS
SCUBA
L.A. CALIF."

I have not thrown them away since I lost those tanks in about 1986. So they've been with me on at least two moves, and are now sitting on my desk.

Anyway, Shackle, this is good news for your attempt to rebuild these valves. Please PM me and we can see what can be done. They have done me no good for twenty years, but they are still in decent shape. And Duckbill, they are marked "Healthways," and have that same cap on top that is shown on the left drawing above. I wonder whether at that time one company made all these valves, and simply made slight variations for each one.

John

[duckbill]

My Healthways valves seem to have a pressure-release feature. When you turn the valve off, you can then push down on the top/handle to bleed the air out of the system for removing your regulator. I don't have one mounted on a useable cylinder or I could tell you for sure, but it does work at the 300 psi which is in the tank now.

Shackle, when you get back, does your valve say "US Divers" or "Healthways"? Double check the nut on top and see if it's a domed cap nut, or flat with a screwdriver slot with the stem coming up in the middle. That will speak volumes.
Good luck.

[SeaRat]

Duckbill,

Now you have me curious. I have one of the two valves that seems to act like this. I'll take it apart tonight and look.

John

[shackle]

Duckbill and SeaRat,
The valve is a Healthways and it has a domed cap. The threads on the brass stem look to be ok. I've looked for the cap, but can't find it.

[SeaRat]

Shackle,

From what you've said above, I take it that you have twin 38s set up with these valves. If so, you probably have a yolk to hook the two together so you can use your double hose regulator. If this is correct, then the valves I have would be good for you to use. We can discuss it via PM if you would like one or both of these valves.

John

[SeaRat]

Duckbill,

You are correct, and the Healthways valves are not quite the same as the US Divers valves shown above. The Healthways K valves have a spring inside the stem which pushes the stem up against a nylon washer to ensure that the valve is tight against the sealing surface. I had inadvertently left that spring out of the one valve, and did find it in my tool box. It is now happily inside the valve, doing its job again.

I don't think that this was originally thought of as a means of depressurizing the valve at low pressure. Rather, I think it was a means of ensuring a sealing surface upon pressurization of the valve, thereby eliminating that little "puff" of air upon pressurization that some of these valves had until they sealed themselves. Healthways did a pretty good job of designing these valves and regulators.

I looked a bit harder in Fred Robert's book, Basic Scuba[/B] and found the Healthways valve parts diagrams on page 274. Here's the diagram as a whole:


And here's the blowup of the Healthways K valve:


Healthways did a very nice job of designing these valves. You can see the spring that I mentioned above as part number 37. Another interesting point is that there is a part number 42, and it is described as "H.P. gauge plug "K". Interesting...I don't think it is the common thread for gauges, but that's what it states.

John