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Post by surflung on Jul 7, 2021 5:55:07 GMT -8
Eb, great write-up on your vintage dive weekend! Did you know that Bill Arpin designed the DivAir to work on double tanks/double manifold too? The L-shaped bracket that holds the lever is designed to be rotated 90 degrees to position the lever vertical to fit between twin tanks. You just have to reposition the screws holding the bracket into the pre-drilled alternate holes beneath the bracket. My 2psi. Hey Mark, Thanks for the tip. I really like diving the DivAir and was kind of disappointed not to use my Twins. NUTZ! I did the pivot but it still won't fit my double manifold... I think it's meant to fit a double when the valve is sticking UP. Mine are all oriented down. BTW - SwimJim has the older model that you can't pivot... But his lever is already sticking up and will probably work with a double manifold if the valve is oriented up. I think the ones with the lever sticking up were meant for the diver to just reach back and switch the lever manually. The newer, pivotable lever was (I think) intended to work with a pull rod along the side of the tank like other reserves. There's a really good description in the Basic Scuba 1st Edition. It even tells how to raise and lower the pressure at which the reserve can be set.
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Post by scubalawyer on Jul 7, 2021 6:54:24 GMT -8
Hey Mark, Thanks for the tip. I really like diving the DivAir and was kind of disappointed not to use my Twins. NUTZ! I did the pivot but it still won't fit my double manifold... I think it's meant to fit a double when the valve is sticking UP. Mine are all oriented down. BTW - SwimJim has the older model that you can't pivot... But his lever is already sticking up and will probably work with a double manifold if the valve is oriented up. I think the ones with the lever sticking up were meant for the diver to just reach back and switch the lever manually. The newer, pivotable lever was (I think) intended to work with a pull rod along the side of the tank like other reserves. There's a really good description in the Basic Scuba 1st Edition. It even tells how to raise and lower the pressure at which the reserve can be set. Well shoot. I'll have to put my DivAir back on my twin 38's and see how they fit. Mine is the last model made with the Fibreglass body and I used it successfully on the small twins. Now you have me questioning my sanity. M
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Post by nikeajax on Jul 7, 2021 7:47:51 GMT -8
Mark, we've been questioning your sanity the whole time Sorry son, ya walked into that one JB
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Post by SeaRat on Jul 16, 2021 12:05:26 GMT -8
Well, I completed my test of the twin J-valve on doubles configuration. I had my twin 40s with just under 500 psi in them of air, left over from a dive earlier this month. Onto that I put my Calypso-J regulator. The manifold is a almost new Aqualung solid bar J-valve manifold.
I pressurized the regulator, then took a breath. No hint of the J-reverse upon inhalation. So I used the purge button on the Calypso to simulate my using the regulator, and the pressure dropped quite fast (it’s a good regulator). At between 250 and 300 psi I stopped purging, put the regulator in my mouth and breathed off it. There was a noticeable restriction in breathing, not full, but noticeable. So I pulled the reserve on the Calypso-J, and breathed. No restriction noticed.
At this point the J-reserve in the Aqualung solid bar manifold was still in place, so I purged the regulator until the pressure gauge on the Calypso was at near zero, and breathing became again very difficult. Then I pulled the J-reserve rod on the manifold, and the two tanks equalized at about 240 psi on the Calypso SPG. There was again no restriction, so I left the tanks (we were headed to the store in a few minutes from then). The tanks now have about 240 psig and are ready to be filled at the LDS.
My conclusion is that the use of a regulator J-valve on the center section of the twins, along with the manifold J-valve, does provide double the amount of air in J-reserve. The Calypso-J spring withholds about 300 psig, while the SPG on the Calypso-J continues to read true tank readings. Breathing that down to zero on the Calypso-J’s SPG still holds 500 psi in the reserve tank from the solid bar manifold’s J-valve. Pulling the rod equalizes to approximately 250 psig.
I have a second set of twins with a J-manifold on it, and I may next try this in the water.
John
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Post by SeaRat on Aug 16, 2021 16:26:03 GMT -8
Today I finally did my test of the in-line J-valve usage. I started today's dive with my Dacor R-3, with James' silicone diaphragm, and it performed very well. The unit started out with about 900 psig (no, it wasn't full, but that made for a good experiment). Then, after 19 minutes of diving, I surfaced, swam to the river's bank, and took off my SCUBA unit. I had decided to change out the Dacor R-3 for my Calypso-J regulator, so that I had the 500 psig spring J-valve on the manifold, and a 300 psig J-valve on my Calypso-J. Tthe Calypso-J was in the innertube float, so the switch would be fairly easy. The Calypso-J was center mounted, and so it drew air from both cylinders, whereas the manifold J-reserve held back 500 psig in one cylinder. My twin 45 cubic foot cylinders (at 1800 psig) were down to 500 psig when I made this switch. It took me about 10 minutes to get the SCUBA off, make the switch, and put it back on in waist-deep water. Once on, I headed out again to deeper water. After only a couple of minutes I started getting the restrictions noticable on the Calypso-J. At first it was only the "swoosh" of the Venturi, then it got a bit more difficult to get air. So I pushed up on the bottom of my twin-tank SCUBA, reached over my shoulder, found the regulator and then the J-reserve on it, and tripped it. Immediately the breathing difficulty went away, and I swam down into deeper water. I found a kayak paddle, actually half of one, and picked it up. I also saw two, then two more, juvenile small mouth bass. Then I noticed a larger smallmouth bass, about a pound or so, and followed it for a while. After about six or seven minutes, I again got the breathing restriction. I looked at my SPG, and it read zero (it had read 300 psig with the Calypso-J restriction). So I reached around again and found the J-valve pull rod, and pulled it. I could hear the air equalizing, and read the SPG; it was at about 250 psig, just where it should be. I was managing my line to the float, and took up a lot of the slack from the deeper dive, then swam to the surface. Surfacing near the take-out point on the boulders, I switched to my snorkel (Scubapro Jet Snorkel), cleared it, then found my inflator for my Para-Sea BC. I took out the snorkel, and started orally inflating the BC. The first two breaths into it necessitated me finning a bit to get my mouth clear, then the buoyancy of the BC allowed me to keep my mouth out of the water while inflating the BC fully. Once I had inflated the BC, I swam to a place where my foot holds were available for exiting on the rocks, took off my fins, grounded my float, and stood up. I took off my mask and spit out my snorkel (I keep the snorkel in my mouth in case I slip and do a face-plant on the rocks. The dive was over, but not the exercise workout. I still needed to get me, my SCUBA on my back, my float, and my fins up to the car. That was over 100 yards away, and some 100+ feet of elevation upwards. The first part of this exit is actually a rock-climbing exercise, in full scuba, with my float and fins. Then the paved trail goes up at quite an angle, and finally it levels off and I can walk to the road and my car. It makes for quite a workout, and renews my skills at rock climbing too. No photos or video of this exercise; I left the camera at home, as I still haven't processed the last three videos I have made. But this dive proves that the use of two, in-line J-valves, is a viable alternative in dark water to the SPG. John PS, here’s the setup, but on a different set of doubles: IMG_1464 by John Ratliff, on Flickr
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Post by Jim Perdway on Aug 25, 2021 18:53:46 GMT -8
On a dive the other day was my first time using the J-valve although I also had an spg. When I pulled the rod I noticed a 2-300 psi jump to about 7-800 psi. Does this indicate that the valve is not functioning properly? (Should it be pretty much right at 500 when it’s pulled)
I’m not filling tanks myself, but I’m wondering if I need to pay extra attention that the tech has the valve either up or down during the process.
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Post by SeaRat on Aug 25, 2021 19:52:53 GMT -8
On a dive the other day was my first time using the J-valve although I also had an spg. When I pulled the rod I noticed a 2-300 psi jump to about 7-800 psi. Does this indicate that the valve is not functioning properly? (Should it be pretty much right at 500 when it’s pulled) I’m not filling tanks myself, but I’m wondering if I need to pay extra attention that the tech has the valve either up or down during the process. For a J-valve fill, the J-reserve needs to be in the non-reserve area (down) before filling. Otherwise, you won’t get a full fill. I assume you have a single tank. When pulled, you should get about a 300 psi jump. BUT, some Scubapro valves have an adjustment screw on their top which makes the J-reserve into a 500 psig reserve. IMG_1022 by John Ratliff, on Flickr Here is the Scubapro valve with the adjustable spring tension for the J-valve. Note that it is in the “UP” position, which would not be good for filling a tank, but is the position you want for the dive. IMG_1009 by John Ratliff, on Flickr Looking down on the top of this valve, you can see a screwdriver slot in the top. If that is pushed down and turned, the spring tension is adjusted from 300 psig to 500 psig (approximately). You will see that the screw adjuster is seated down deeper at the 500 psig setting. This setting adjustment can be done when the tank is full, but must be done without a regulator on it as when it is pressurized it cannot be accomplished. John
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Post by Jim Perdway on Aug 25, 2021 20:31:58 GMT -8
Thanks John- the valve I was using was a US Divers and my other ones are Dacor, so would they very likely be 300 psi (one Dacor is on set of doubles)? When it became difficult to breath, if working correctly should the gauge have read close to zero psi at this point, and then 300 after pulling reserve?
I want to get a good feel for these things before doing full tank DH dives. So far I’ve just been weaseling out and switching over to single hose to finish a tank off
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Post by SeaRat on Aug 25, 2021 22:34:16 GMT -8
Thanks John- the valve I was using was a US Divers and my other ones are Dacor, so would they very likely be 300 psi (one Dacor is on set of doubles)? When it became difficult to breath, if working correctly should the gauge have read close to zero psi at this point, and then 300 after pulling reserve? I want to get a good feel for these things before doing full tank DH dives. So far I’ve just been weaseling out and switching over to single hose to finish a tank off The J-valve on the doubles, if it is a true doubles manifold, is set at 500 psig. When you pull the reserve rod, it equalizes into the other cylinder, and you end up with about 250 psig. Yes, your gauge will be at close to zero when the breathing is difficult, and then once the J-valve is pulled, will be about 300 psig, maybe a bit more because many (including me) can sense it before getting to zero. The only unit I’ve used where this isn’t true is the UDS-1 three-cylinder unit by U.S. Divers Company, which could be breathed down to where you had only about 2 or 3 breaths before empty without feeling it. It had a reserve set at about 750 psig, as it had to .equalize between three cylinders. Here is a photo of the insides of the UDS-1: Okay UDS-1 with top case off by John Ratliff, on Flickr John
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Post by antique diver on Sept 7, 2021 18:06:52 GMT -8
The oldest SPG that I have seen was attached to the manifold on my 1955 Siebe Gorman doubles. In 1970 we may have sold two SPG's in a year, but I began to see the benefits and sales picked up gradually over the next couple of years. It did take a long time for them to be recognized as a necessity. For some.
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Post by antique diver on Sept 8, 2021 17:13:22 GMT -8
I like J-valves. I don't like getting scraped or cut on the little SS cutout sharp-edged tab rod retainer found on many tank bands... I guess I'm a bit clumsy. Although I have used the aftermarket L-shaped metal retainers that slip under tank bands, I don't care much for them sticking out. Not really hazardous, but not really streamlined, and they can get bent easily in transit. The little homemade retainer below is just a short piece of nylon webbing with holes melted in it with a hot nail. Actually I prefer to make them shorter, with just one end protruding from the tank band. That makes it easier to remove the retainer and J rod when changing tanks, etc., and it still does a good job of keeping the rod under control if you keep the hole and rod right up close to the tank band. I'll be using just a single hole in the strap in the future for more convenience.
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Post by nikeajax on Sept 8, 2021 17:25:49 GMT -8
Bill, could you please show us more of the above set-up? Man, that looks funky an' swell Jaybird
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Post by antique diver on Sept 8, 2021 19:52:15 GMT -8
Hi Jaybird, I appreciate your interest. I acquired this 1955 set of Siebe Gorman doubles at least 30+ years ago. We were in the diving business from 1970 thru 2000, when we sold the shop to a long time employee. I kept the interesting old stuff. Along the way we had acquired a pretty good collection of vintage gear from people updating or just cleaning house, and this was one of my favorites. This and the Spaco that came with it had belonged to this guy's father, long since deceased. They seem to be the same size as domestic 38's, with 1800 psi and the 1955 manufacture dates stamped into a ring on the tank necks. The family had kept it for many years, and I suppose they decided it was time for a good garage cleanup. I'm certainly glad it didn't get set on the curb as trash! This is how it looked when we got it, and you can see the gauge that I posted earlier attached at the manifold.
Below is how it looks today, with the cotton strap harness I made in 2006. I wanted to finally take them diving, but due to really odd thread size and taper I couldn't find a hydro shop that could test them. I finally ended up making an adapter to fit the threads, and a hydro facility used it for the testing. They were really doing me a favor since they had Canadian markings, so they were unable to stamp them, which was fine with me. I had watched the whole testing procedure, and it was done properly as if they were ICC/DOT cylinders. Some will recognize the Canadian made hoses on the Divair. Flip side: They are a blast to dive with, and I use them without the gauge, not wanting to risk it flooding. Using the "decanting" method of air management it is real easy to keep track of your remaining air supply with no gauge. I won't go into detail here, but will be glad to explain if someone wants the rundown on that. It involves using the valves during the dive, and they are very easy to access at the divers lower back. Odd thing is I haven't used the Spaco with this exact set, but I will be doing that soon I hope.
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Post by tomcatpc on Apr 2, 2022 16:28:00 GMT -8
Diggin' the blue hoses on the DivAir!!! I dive with a J-Valve almost every time I dive. I only have one tank with a K-Valve. I think that a lot of modern Divers would be down-right horrified to dive with a J-Valve only. Me...I love diving with as little as I can get away with and never had a problem with the J-Valve. Mark
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