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Post by vance on Oct 28, 2023 14:07:23 GMT -8
I just picked up a Northill reg. I made a low-ball offer and ended up the only bidder on eBay. I know members of the board have done some work on these, but I don't remember any successful rebuilds. I remember that James had looked into making new diaphragms, but, whether they were successful, IDK. I'd like to get this one working again, but the diaphragm assembly is, as yet, a mystery to me. Once I have it in hand, we'll see what it needs!
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Post by nikeajax on Oct 28, 2023 15:49:07 GMT -8
Very cool! I think Skip has one of these/those too, so I'm sure he'll have something to say... It's reminding me of a water-pump on an old car.
JB
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Post by snark3 on Oct 28, 2023 16:30:26 GMT -8
I actually have 2 of them. The diaphragm is a complex item on these. They're plastic with rubber surrounding it, and the exhaust is handled by another diaphragm on the plastic. The rubber exhaust diaphragm on both of mine is toast. I did speak with James about trying to make a replacement. I had no way get accurate enough measurements and curvature to make a replacement. The more I looked at them the more I believe they're a horrible design.
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Post by vance on Oct 28, 2023 18:04:13 GMT -8
That's so not encouraging! Well, I hope I can get this thing to work. Who knows what's inside....
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cg43
Senior Diver
Posts: 91
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Post by cg43 on Oct 29, 2023 4:58:28 GMT -8
Hello It's all in the drawings on CG45.com , the old and the newer version . A very interesting design , first the old one jear 1958 . Fig. 4 shows reg valve closed and hight tank pressur Fig. 2 shows reg valve open and low tank pressure . There is no drawing from the old mouthepiece . Even if there is no gasket , the inlet horn room 17 and the main diaphragm room 18 can be considered to be nearly isolated from each other . In this case there can be no exhalationvalve in the mouthpiece because the air to move the diaphragm (open the valve) must be sucked by the exhale hose . There is one thing not so good in the old version . Hight tank pressure moves up the hp seat and therefor the outer lever end down . The movement of the leaver end is magnified by the relationship of the leverarms . I don't think that's to bad because during hight tank pressure the valve only needs littel hub . The new version avoids this because the Fulcrum Tube Part 13 moves up the support points of the levers at the same as the hp seat goes up . The levers stay the same angle . This has to be taken into attention for design a new diaphragm/ exhalevalve . In the new version room 17 and room 18 are not approximate isolated because all the parts 6 , 9 , 13 are not sealed . In this case an exhale valve in the mouthepiece or hose is fine . Both versions have the disatvantage that the air need to move the diaphragm acts as death space . There shall be no insurmountabel difficulties to build new diaphragm/ exhalevalve parts . greetings Rainer
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Post by james1979 on Oct 29, 2023 17:05:34 GMT -8
I have to many irons in the fire to make any timeline promises, but if there is a donor unserviceable diaphragm available I can take a swing at functional replacements. I'm getting on time that I need to print some new molds anyway!
Respectfully,
James
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Post by vance on Oct 29, 2023 17:14:29 GMT -8
If there's a good donor diaphragm, I'll send it your way!
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Post by snark3 on Oct 30, 2023 11:21:02 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.
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Post by vance on Oct 30, 2023 12:00:36 GMT -8
Is the rubber for the main diaphragm still good on either of them?
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Post by nikeajax on Oct 30, 2023 17:11:48 GMT -8
Hmmmmm? I know, wait until Phil's gets here, but I can't help wonder if the diaphragms need to be that complicated? I'm hoping that James can just tweak his Dacor design and that will be good enough/better JB
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Post by SeaRat on Oct 30, 2023 17:56:11 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.
These are interesting photos. What they tell me is that this regulator had been designed to have at least 2 inches of water pressure for breaking effort, in order not to leak air in certain positions. 'Just an observation. But the surface area of the exhalation through the diaphragm is fairly large, which would make exhalation pretty easy. And, it is exhalation that causes more effort than inhalation. John
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Post by snark3 on Oct 31, 2023 4:08:37 GMT -8
Is the rubber for the main diaphragm still good on either of them? The rubber for the main diaphragm is good on both of them. The exhaust valves are petrified on both.
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Post by james1979 on Oct 31, 2023 5:38:50 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
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Post by vance on Oct 31, 2023 7:29:43 GMT -8
That is a ridiculously complicated diaphragm. A mushroom in the middle seems like it could be a winner, depending. We'll see when I get the thing!
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Post by vance on Oct 31, 2023 7:46:46 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.
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