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Post by nikeajax on Nov 22, 2023 15:15:22 GMT -8
Not to deviate too far from the subject of Dräger regs, but... Could someone explain, in simple terms/nicely/neatly, why using a non-return-valve at the end of the corrugated-hose would have a different result than that of a DH? The Demone doesn't have a non-return-valve, so I can see how that might be problematic with constriction of the flow of escaping gas and hose flooding, but physics and math hurt my brain JB
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Post by vance on Nov 22, 2023 18:13:54 GMT -8
I am equally confused. A flooded hose will need a lot of effort to expel the water. A non-return that closes the end of the exhaust hose to prevent water intrusion would solve the problem.
The OverPressure regulator had a non-return valve that had an unique wagon wheel. It had a center hole that fitted over the small hose, and a radial non-return. Truly different than any other that I know of. There is a thread on the board that shows this.
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cg43
Senior Diver
Posts: 91
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Post by cg43 on Nov 23, 2023 16:14:57 GMT -8
Hello
It is nessesary to vent the Demone hoses with water on the lower ends to avoid freeflow if the upper ends are above the 2. stage diaphragm ! And full of air they will float up most the time . Yes the flooded hoses will first need a lot of effort to expel the water . Thats a big drawback and probably one reason the Demone disapeared quick . You can read about in CG45 links . If you close the upper ends with auxilary one way valves this will not change much . The water will go in on the lower end and the air will go out on top .
Greetings Rainer
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Post by nikeajax on Nov 24, 2023 9:00:46 GMT -8
Hello It is nessesary to vent the Demone hoses with water on the lower ends to avoid freeflow if the upper ends are above the 2. stage diaphragm ! And full of air they will float up most the time . Yes the flooded hoses will first need a lot of effort to expel the water . Thats a big drawback and probably one reason the Demone disapeared quick . You can read about in CG45 links . If you close the upper ends with auxilary one way valves this will not change much . The water will go in on the lower end and the air will go out on top . Greetings Rainer EXCELLENT--THANK YOU! That was very concise and very easy to understand Jaybird
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Post by SeaRat on Nov 24, 2023 17:11:15 GMT -8
I am equally confused. A flooded hose will need a lot of effort to expel the water. A non-return that closes the end of the exhaust hose to prevent water intrusion would solve the problem. The OverPressure regulator had a non-return valve that had an unique wagon wheel. It had a center hole that fitted over the small hose, and a radial non-return. Truly different than any other that I know of. There is a thread on the board that shows this. As I'm one of maybe two people here (or Rainer may be the third) who owns this regulator, I will talk about that nenreturn in the mouthpiece. Here's the parts diagram for this regulator (the Overpressure Breathing regulator). DX Overpressure Schematic by John Ratliff, on Flickr Note that there are two nonreturn valves, one in the intake of the mouthpiece, and one at the box for the exhalation. The intake nonreturn is unique, in that it had two connection rubber cylinders, or prongs, that were molded into the nonreturn, and a hole in the middle for the inner hose metal fitting. But in removing that nonreturn, those two rubber cylinders, or prongs with a molded stopper, broke off. So I had to do some creative work, using dental floss (the toughest thread you can find). Here's the results: IMG_2204 by John Ratliff, on Flickr Note that the nonreturn fits onto a metal disc that slides over the inner tube fitting. Here's a shot from the other side. IMG_2203 by John Ratliff, on Flickr Note also that there are two openings for air to pass through. I think this dampened the Venturi somewhat too. The mouthpiece nonreturn served to not allow the diver's breath back into the intake hose (the problem with the Dräger regulator with a single hose). But you also have to appreciate that there is another nonreturn, in the exhaust outlet tube assembly, which brought the exhaust right back to the center of the main diaphragm. This is what the Cousteau patent was all about, having the exhaust centered on the main low pressure diaphragm (in this case, as it is a single stage unit, the only diaphragm) in order to prevent the freeflow of air due to differences in pressure. The problem with not flooding the inner tube mod of a single hose regulator, or the Demone regulator, is that inevitably (as Rainer pointed out), there will be several inches of difference in the water pressure between the main diaphragm and the exhaust, which will lead to uncontrolled freeflow of air. Here is a short video of me using the Overpressure Breathing regulator to illustrate an old-time method of talking underwater. Note a couple of things. Firs, that this is a very quiet regulator. Second, that one hose floods. After recording the video, I realized that I had said that the right hose floods; in actuality when wearing it the exhalatioun hose floods, which is on the right side of the screen, but is the left hose when wearing it. The non-return in the mouthpiece keeps the inhalation hose from flooding. John
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Post by vance on Nov 24, 2023 17:47:24 GMT -8
I've owned several in the past. I didn't like the forced feel of the intake. It is like the single hose MR12 with the venturi tube.
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cg43
Senior Diver
Posts: 91
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Post by cg43 on Nov 25, 2023 3:56:16 GMT -8
Hello John
Very nice video ! The Champion mask was the first mask I ever owned . Your repair looks very convenient .
I never had a "OverPressure Regulator" but I made the design on paper just for fun .
As allways there are advantages and disadvantages on a design . The advantage is that the diver don't has to suck a lot of air through the inlet hose . But now , if there gets water into the inlet hose , this water is not be blasted out properly by the littel among of air going through the outer inlet hose . A fine working non return valve in the mouthpiece is nessesary . But that's not a big deal .
The air : Let's assume the air in the tank has the temperatur of the ambient water . Air expandet cools down . Why not heat it up near to the water temperature with a heatexchanger ? The heatexchanger need's volume , surface connected to the water and cost's money . But if we allredy spend this effort's why shall we throw it away ?
The ordinary doubel hose reg. has big surfaces to the water , the corrugated hoses and the turbuled airflow inside are good for heat exchange . The air coming out is only a littel bit under water temerature . Not so the air coming out of a singel hose reg. , that's much cooler . The overpressure sadly throws this big advantage away . His IP hose surrouded by air is a bad heat exchanger .
I had some papers about air temperature measurements , but first I had to find them .
Greetings Rainer
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Post by antique diver on Nov 25, 2023 5:23:59 GMT -8
I've owned several in the past. I didn't like the forced feel of the intake. It is like the single hose MR12 with the venturi tube. I found that the venturi can be made adjustable internally by varying the amount of airflow into the can by way of a modified Mistral nozzle. I enlarged the side orifices a bit, and tried several main outlet orifice sizes. The more airflow into the can the less blast into the mouthpiece. It took a whole lot of trial and error on the bench and a few dives, then once I had the right combination the threaded sleeve was secured with medium Loctite. I love the way this DX performs, but it still might be a little feisty for some folks. There is a little additional helpful control of the venturi effect by positioning the tip of tongue to roof of mouth.
Bryan (VDH) had generously provided me with several repro Mistral nozzles to facilitate the experimentation.
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cg43
Senior Diver
Posts: 91
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Post by cg43 on Dec 21, 2023 13:54:11 GMT -8
Hello
A few more information about the Dräger Delphin II .
This single stage reg. has an downstream valve !
Long ago I had one and as I remember the diameter of the orivice was only about 1mm. The reg. was used in ambulance cars fixed to oxygen zilinders . Probably he was designed for this use and not for diving . With littel changes it became a not so good diving reg. that was ceap enough . Although from Dräger , for most german diver's this was no true diving reg. Today I would like to have one because not all of my regs. must go down to 300 feet anymore .
Greetings Rainer
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Post by vance on Dec 21, 2023 16:26:15 GMT -8
My feeling as well. I am not interested in deep diving any longer. Interesting regs that work well at 30 meters are good enough!
You can see 95% of marine life at 50 fow. How deep do recreational divers need to go?
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