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Post by nikeajax on Oct 31, 2023 8:04:08 GMT -8
Basic Scuba shows it having a very peculiar lever system, three radiating levers and something in the middle too... Anyway, I'm thinking it has to have that middle part, so perhaps like the Dacor Olympic, it could have multiple small diaphragms C'mon Phil we're waiting! JB
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Post by SeaRat on Oct 31, 2023 9:31:32 GMT -8
I think that a simple mushroom valve in the middle of the diaphragm would work here, but would rather see the original designed exhaust completed. That way it could be tested. Here's a different view, from the CG-45 website: The reason I'd like to see this original design in the diaphragm is because of the claims made my Northhill. They claim, "Breaths like a breeze." And, "Easier breathing at all depths and all positions..." It's a single stage, balanced regulator design, which may make those claims correct. I'd like to see it determined. Everyone here should actually visit the CG-45 website on the Northhill, if only to again see Zale Perry and how she was involved with this regulator. www.cg-45.com/regulators/Northill/index.shtmlJohn
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Post by snark3 on Oct 31, 2023 9:33:39 GMT -8
This reg has three levers that ride in the center plastic of the main diaphragm. I thought about the possibility of 3 small mushrooms. I think there's potential in that idea.
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Post by nikeajax on Oct 31, 2023 10:35:09 GMT -8
John, I appreciate what you're saying, but it's easier in the long run to make it use something off the shelf: that weird exhaust valve has an extremely high propensity for creating a shelf-queen again... How long has Skip been fighting this? JB EDIT: Did you know that the Curve Dash Oldsmobile was the first car, not the Ford, to be built on an assembly line? I bring this up because it was also the first car to use interchangeable parts! Interchangeable parts make vintage scuba much more fun
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Post by james1979 on Oct 31, 2023 11:16:23 GMT -8
Just looking at it, the exhaust diaphragm portion should be an easy mold to make for replacing in silicone. The main diaphragm looks to be a bit of a pain, though. To riff off JB's idea, I think ( pending what the lever contact point looks like) that a variation of the first gen Calypso diaphragm design might be the ticket (and allow for tuning to a lower cracking effort, per John's observations). Respectfully, James It appears to have 3 diaphragm levers which contact the hard plastic center (#4). A mushroom might be fitted to the center after blocking the oem valve openings. Probably just do a complete new main diaphragm similar to the Dacor exhaust diaphragm, just making sure there is enough outer rim on the pressure plate for the levers to use.
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Post by james1979 on Oct 31, 2023 11:20:56 GMT -8
I think that a simple mushroom valve in the middle of the diaphragm would work here, but would rather see the original designed exhaust completed. That way it could be tested. Here's a different view, from the CG-45 website: The reason I'd like to see this original design in the diaphragm is because of the claims made my Northhill. They claim, "Breaths like a breeze." And, "Easier breathing at all depths and all positions..." It's a single stage, balanced regulator design, which may make those claims correct. I'd like to see it determined. Everyone here should actually visit the CG-45 website on the Northhill, if only to again see Zale Perry and how she was involved with this regulator. www.cg-45.com/regulators/Northill/index.shtmlJohn I should be able to make a new exhaust valve (just a slightly coned silicone ring) that Skip can use on one of the diaphragms with a good main portion. Then I can use Phil's measurements to go full on new design for practical use, a la JB's comments.
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cg43
Senior Diver
Posts: 91
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Post by cg43 on Oct 31, 2023 12:24:13 GMT -8
Hello John
First , thanks for the editing (CG45 drawings).
"They claim, "Breaths like a breeze." And, "Easier breathing at all depths and all positions..." It's a single stage, balanced regulator design, which may make those claims correct. I'd like to see it determined."
The old version has something common with the USD Overpressure . The diver is moving the diaphragm by a hose (the exhaust hose) with (nearly) no flow and the air flows by the inhale hose up to te mouthpiece without the need to suck the air through the inhale hose . This may breath like a brezze . I would try a muschroom valve in (or short out) center the main diaphragm and no second exhale valve . Old or new version doesn't matter .If nessesary tune the cracking pressure with washers under one of the two springs .
greetings Rainer
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Post by snark3 on Oct 31, 2023 14:02:56 GMT -8
It appears to have 3 diaphragm levers which contact the hard plastic center (#4). A mushroom might be fitted to the center after blocking the oem valve openings. Probably just do a complete new main diaphragm similar to the Dacor exhaust diaphragm, just making sure there is enough outer rim on the pressure plate for the levers to use. It appears from the posted drawings that the outer ring of the diaphragm can be removed from the plastic. This outer ring is flat and could be made out of a sheet of 1/16 or 1/8 silicone. The exhaust valve ring is another story. I think you'd need the plastic piece to get the proper dimensions and the curve to make a mold in order to make a silicone replacement
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Post by vance on Nov 2, 2023 13:12:05 GMT -8
Here is a picture of the diaphragms from my Northills. The round thing that looks like a donut is the exhaust valve. It's not flat.
I got the Northill today. It's in nice shape, but the diaphragm is like Snarky's. The rubber for the main is ok, but the exhaust is dry and cracked. It's intact. How did you get the exhaust diaphragm off the plastic, Skip? Does the plastic part come apart? I'm afraid of putting any pressure on it.
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Post by nikeajax on Nov 2, 2023 15:55:32 GMT -8
Phil, I mentioned this to Skip, but, I'm wondering if you could make a diaphragm/valve by cutting out two rings: the I.D. is the same, but the O.D. of one is smaller, then perhaps glue them together, or not. The end result is more or less a gradation, or taper on the leading edge, thus giving you a dynamic resistance. Does this make sense, I hope?
JB
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Post by vance on Nov 2, 2023 17:06:22 GMT -8
Maybe. The exhaust ring is flat by the hole, and angles downward to seal on the plastic. It doesn't seem very complex. If he's willing, I'll send the whole diaphragm to James for a look-see.
I rebuilt most of the regulator today. It's different! The valve is not like anything I've seen so far. It's supposed to be balanced. Not sure.
There are a lot of o'rings that need replacing. This is the only regulator I've ever had that the o'rings were as hard as plastic. Not one came off w/o splitting.
I'm having a bit of trouble with the reserve mechanism. Can't quite get it back together properly. Not sure why, but I'll keep at it!
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Post by snark3 on Nov 2, 2023 18:17:23 GMT -8
Phil- You're right the exhaust ring is flat where it goes under the lip. One of mine was cracked so I broke it on the crack and it just slipped out from under the lip. I proposed sending the whole setup to James too, as I couldn't see how to tell him the proper contour
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Post by vance on Nov 3, 2023 7:14:07 GMT -8
Here are some photos. My diaphragm. Note the cracks through the exhaust valve. All the pieces. Note the bent yoke screw from banging around in the box: Mostly reassembled:
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Post by vance on Nov 3, 2023 7:52:26 GMT -8
Apparently, the first production models had a mushroom valve in the center of the diaphragm. From CG-45:
1954 - Northill Air Lung: The first two numbers of the serial number indicate the year. The label is green, Northill Company and Garrett Corporation are listed with a patent number, and the label was attached using adhesive The internal metering valve (high pressure valve assembly). is held in place with a “C” (or Truarc) clip, and all internal working parts are made of polished brass with the exception of the springs. The main inhalation diaphragm is made of thin rubber and yellow fiberboard riveted together and in the center is a mushroom exhaust valve. The reserve assembly has a cast “limit lever sleeve.” The lever itself is made from stamped-out sheet metal and is held in place with a C (or Truarc) clip. The corrugated hoses are held in place using brass bands, and the mouthpiece is a cast fitting, which carries a push-button cut-off valve and removable mouthpiece. (NEDU report 1954).
Huh.
Mine is a 1956 model, as the first digit of the serial # is the year of manufacture.
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Post by antique diver on Nov 3, 2023 9:00:46 GMT -8
I have always thought those were cool and rugged looking regulators, but haven't had one. I do know where one is that's missing a reserve lever, and hoping I can do a little trading with the current owner. I would need to make a decent looking lever, so your photo helps. I'm curious about the overall weight, so if you get a chance check that out. BTW, I think the bent yoke screw is more indicative of a tank falling over with reg attached instead of banging around in a box.
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