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Post by SeaRat on Oct 19, 2022 11:40:13 GMT -8
Hi Luis, I always read your posts concerning the science involved in making regulators work, with interest. Your explanations above are pretty dense, but clear enough. As far as my own work with making and or modding parts for regulators goes, I am not inventing anything. Some might call a couple of ideas I've implemented novel, but they are admittedly simple hot-rodding. I have not contributed anything original to regulator design or development. Perhaps I can take credit for some refinement, but I have only accomplished what a car enthusiast might by installing disk brakes on a Model A Ford. Adding an improvement or safety feature to an obsolete design might be innovation, but not invention. I don't need a lot of data or preliminary testing to make a very workable second stage, an HP port for a J valve, a single stage to DH conversion, and the like. That's already been done, and data is readily available thanks to you and others. I incorporate the ideas and parts I need or like (or already have!) from existing designs. For example, my second stages depend on elements from several different second stages, such as the Trieste lever double bend foot, the single hose style castle, USD DAAM/RAM dimensions, and USD poppets and springs. In a couple of my conversions, an HPR would have worked well, but I wanted the challenge of making my own. This takes a little trial and error, but mostly from the fabrication side, not so much getting the thing to work well when it's done. Where I have gotten into no man's land on a project is, as you said, the single stage regulators. This requires much more trial and error to achieve a good result in terms of venturi, bleed jets, air directors/nozzles, and the like. These can be lung-busters if you aren't careful. For example, the single stage DAAM (SSAM) nozzle will need more work on the air jetting. It needs a wide range of adjustability in order to simplify finding a suitable starting point and working toward an optimal venturi. BTW, you said above that the DSV doesn't tamp down the venturi, but simply directs the air flow into the diver's mouth. What I was talking about is how a regulator that free flows uncontrollably with a regular US Diver's mouthpiece often does not when the DSV mouthpiece is used. In this case, the air isn't directed into the diver's mouth, the free flow doesn't occur. Others have noted this, and have used the DSV to control a regulator's tendency to freeflow. From my experiments with the deflector in a Healthways mouthpiece, you have to think of the diver's mouth as a part of the system. Taking the mouthpiece out of the mouth provides a more favorable route for the air, and therefore more of a tendency for a free flow. The problem I was trying to solve, which the DSV mouthpiece solves well, is the tendency of a finely tuned double hose regulator to bypass the mouthpiece and therefore waste air with blow-by air exiting the regulator. This happened with the Healthways Gold Label, which needed at least the deflector and an exhaust non-return. Now, two regulators of note, the Mistral and the Overpressure Breathing, provide an example that shows that with the mouthpiece in the mouth, and an open exhalation hose, there really is no possibilty of overpressurizing the diver's lungs. Any excess air will be vented out the exhaust hose. The Overpressure Breathing regulator provides the best breathing of any single hose ever developed. It (for those who don't know) has a hose-within-a-hose concept, and pipes the air directly to the mouthpiece, where a metal tube with holes drilled into it directs the air flow directly down the mouthpiece and into the diver's airway. It does not overpressurize the lungs either, due to the fact that the exhalation hose is available for any excess pressure (though that doesn't happen). Early divers felt it breathed too easily, and therefore caused them to use too much air (a fallicy). They also objected to the potential for a mist to form when water was inside the delfector tube inside the mouthpiece, and actually in the Great Lakes region, where cold water and under ice diving was occurring, caused small ice crystals to form on inhalation and they abraded the diver's mouth. I mentioned the Mistral, as Fred Roberts in Basic Scuba cited the Mistral orifice as the most advanced of the ones used, and that might be a useful item to base your single stage Aquamaster upon. This Mistral orifice allows enough air back into the case to keep it from free flowing, yet performance-wise according to Roberts it "approaches" the performance of the Overpressure Breathing regulator. The Mistral doesn't free flow after inhalation, yet it beat the socks off the Aquamaster/RAM in U.S. Navy Experimental Diving Unit tests, especially at depth. John
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Post by vance on Oct 19, 2022 13:48:08 GMT -8
What I meant by lung busters is the uncertainty of what to expect delivery-wise the first time you take a pull on a new experimental regulator. I learned to be wary of, and ready for, an out of control blast. It doesn't usually happen. Mostly they underperform and need boosting. But, now and then!
The SSAM is an example of one of these. We didn't know what to expect with the nozzle, jet size, bleed jets, and all. It turned out to be WAY too much the first time. Fortunately, I approached it like I would a snarling dog.
I also think I understand that the free flow is a result of a strong stream of intake air blasting through the mouthpiece and out the exhaust hose. This creates a kind of venturi, as well. The DSV baffle does not allow the "second venturi" to occur, since all of the intake air is directed to the diver's mouth.
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Post by luis on Oct 19, 2022 14:01:01 GMT -8
Hi Luis, I always read your posts concerning the science involved in making regulators work, with interest. Your explanations above are pretty dense, but clear enough. As far as my own work with making and or modding parts for regulators goes, I am not inventing anything. Some might call a couple of ideas I've implemented novel, but they are admittedly simple hot-rodding. I have not contributed anything original to regulator design or development. Perhaps I can take credit for some refinement, but I have only accomplished what a car enthusiast might by installing disk brakes on a Model A Ford. Adding an improvement or safety feature to an obsolete design might be innovation, but not invention. I don't need a lot of data or preliminary testing to make a very workable second stage, an HP port for a J valve, a single stage to DH conversion, and the like. That's already been done, and data is readily available thanks to you and others. I incorporate the ideas and parts I need or like (or already have!) from existing designs. For example, my second stages depend on elements from several different second stages, such as the Trieste lever double bend foot, the single hose style castle, USD DAAM/RAM dimensions, and USD poppets and springs. In a couple of my conversions, an HPR would have worked well, but I wanted the challenge of making my own. This takes a little trial and error, but mostly from the fabrication side, not so much getting the thing to work well when it's done. Where I have gotten into no man's land on a project is, as you said, the single stage regulators. This requires much more trial and error to achieve a good result in terms of venturi, bleed jets, air directors/nozzles, and the like. These can be lung-busters if you aren't careful. For example, the single stage DAAM (SSAM) nozzle will need more work on the air jetting. It needs a wide range of adjustability in order to simplify finding a suitable starting point and working toward an optimal venturi. BTW, you said above that the DSV doesn't tamp down the venturi, but simply directs the air flow into the diver's mouth. What I was talking about is how a regulator that free flows uncontrollably with a regular US Diver's mouthpiece often does not when the DSV mouthpiece is used. In this case, the air isn't directed into the diver's mouth, the free flow doesn't occur. Others have noted this, and have used the DSV to control a regulator's tendency to freeflow. Hi Vance I hope what I typed didn’t come out wrong. I was just making some suggestions I truly hope you are having fun doing it… I think some of the stuff you and James are doing are pretty cool. About the flow diverter: the diverter, diverts the flow towards the diver… the diver then becomes a dead-end that can stop or controls the flow. I have measured the flow rate with the same DSV, with and without the diverter in place (no diver in the loop) … I just sucked to initiate the venturi flow and got out of the way. Without the diverter, the flow goes out the exhaust. With the diverter the flow goes out the mouthpiece. But the flow rate (measure by tank pressure drop per minute) is very similar. Honestly, as expected, the flow area in the mouthpiece has some effect, but it is not that drastic. Therefore (if I understand what you are saying), even with my original diverter in the original DSV, what you are seeing, is the effect of the diverter doing the job of diverting most of the flow into the diver’s mouth and the diver controlling the flow. Isn’t that the preferred situation?
The diver is kind of a dead end for the flow.
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Post by vance on Oct 19, 2022 14:23:59 GMT -8
Luis,
Please don't worry about that. I trust that your intent is not to offend, but to educate. I appreciate it.
I was just editing the post above, and your reply appeared before I finished.
I said: "I also think I understand that the free flow is a result of a strong stream of intake air blasting through the mouthpiece and out the exhaust hose. This creates a kind of venturi, as well. The DSV baffle does not allow the "second venturi" to occur, since all of the intake air is directed to the diver's mouth."
I hesitate to use made up terms like "secondary venturi" like I did, but that kind of language helps me to understand, (and I hope others as well), even if not "engineer approved".
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Post by SeaRat on Oct 19, 2022 14:35:17 GMT -8
The only truly “lung buster” regulator if you get the Venturi wrong on it is, to my knowledge, the Scubapro Pilot. That regulator has the potential, if the opening is aimed directly at the mouth, to do damage to the lungs. That is also highlighted in the repair manual for the Pilot. And, the manual states to initiate a free flow by depressing the purge button, not breathing off it, and see whether it stops by itself. If it doesn’t, it needs to be readjusted to take some of the Venturi action off by aiming it (the opening) more at the case. Pilot Repair 5 by John Ratliff, on Flickr John
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Post by vance on Oct 19, 2022 15:00:52 GMT -8
I have never tried a Pilot, but I always found the MR-12 and the OverPressure regulators' air delivery to be too forceful. They make me anxious when using them.
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banana
Regular Diver
Posts: 18
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Post by banana on Oct 23, 2022 9:15:33 GMT -8
I still have plans to revisit that project.... Thinking about incorporating Luis's silincer method on USD exhaust boxes.... This is very interesting for me, having sold my Argonaut, but retained my Aquamaster Phoenix/HPR. Every time I try to imagine a micro port exhaust I see the bubbles quickly recombining. But from what Luis has said this is not entirely the case. I can't say that I have noticed a dramatic improvement in approaching fish with the DH. I've always had good luck with judicious breath control. But I can see the benefit of converting from an exhaust glub to a fizz.
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Post by antique diver on Oct 23, 2022 10:02:58 GMT -8
I still have plans to revisit that project.... Thinking about incorporating Luis's silincer method on USD exhaust boxes.... This is very interesting for me, having sold my Argonaut, but retained my Aquamaster Phoenix/HPR. Every time I try to imagine a micro port exhaust I see the bubbles quickly recombining. But from what Luis has said this is not entirely the case. I can't say that I have noticed a dramatic improvement in approaching fish with the DH. I've always had good luck with judicious breath control. But I can see the benefit of converting from an exhaust glub to a fizz. I think I would prefer the "fizz" too! The glub-glub behind my head seems a bit loud at times.
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Post by james1979 on Oct 23, 2022 10:16:35 GMT -8
This is very interesting for me, having sold my Argonaut, but retained my Aquamaster Phoenix/HPR. Every time I try to imagine a micro port exhaust I see the bubbles quickly recombining. But from what Luis has said this is not entirely the case. I can't say that I have noticed a dramatic improvement in approaching fish with the DH. I've always had good luck with judicious breath control. But I can see the benefit of converting from an exhaust glub to a fizz. I think I would prefer the "fizz" too! The glub-glub behind my head seems a bit loud at times. Well, I have a Trieste exhaust can designed with integrated DBE and what I now christen "the Luis Fizz"... of course, I need to actually get a good print of it and test it. If all goes well, I'll apply it to USD cans too.
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Post by antique diver on Oct 23, 2022 14:35:13 GMT -8
I think I would prefer the "fizz" too! The glub-glub behind my head seems a bit loud at times. Well, I have a Trieste exhaust can designed with integrated DBE and what I now christen "the Luis Fizz"... of course, I need to actually get a good print of it and test it. If all goes well, I'll apply it to USD cans too. James, that sounds like a good idea!
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Post by vance on Oct 23, 2022 15:25:29 GMT -8
This is very interesting for me, having sold my Argonaut, but retained my Aquamaster Phoenix/HPR. Every time I try to imagine a micro port exhaust I see the bubbles quickly recombining. But from what Luis has said this is not entirely the case. I can't say that I have noticed a dramatic improvement in approaching fish with the DH. I've always had good luck with judicious breath control. But I can see the benefit of converting from an exhaust glub to a fizz. I think I would prefer the "fizz" too! The glub-glub behind my head seems a bit loud at times. Bill, all I have to do to be to be reminded about how the single hose exhaust blasts past your ears is to dive a Voit Commander, a ScubaStar, an MR12, etc. They are loud! Most DH regs are a lot quieter, and some are very quiet, like my Misuba Rev5, DA Navys and Broxtons, and two of the HW Scubas. The GL makes some noise, like the Mistral and other DH regs with venturis. My favorite regulator to dive is the Misuba Rev5. It has an HW long valve with balanced Conshelf HP parts installed, and is mounted in Mistral boxes. In addition, it has a "Ghost" air director, and a DBE. This thing is spooky quiet, and delivers all the air I need. This is why it's called a "ghost". DSCF3163 by Vancetp, on Flickr
Here is one mounted in a Scuba:
DSCF3173 by Vancetp, on Flickr
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Post by luis on Oct 23, 2022 20:21:17 GMT -8
I think I would prefer the "fizz" too! The glub-glub behind my head seems a bit loud at times. Well, I have a Trieste exhaust can designed with integrated DBE and what I now christen "the Luis Fizz"... of course, I need to actually get a good print of it and test it. If all goes well, I'll apply it to USD cans too. Hi James, In order to get good silencer results you need very small holes (I am using about 0.040” diameter holes) and so that bubbles don’t recombine right away you need some separation between the holes. I would like to even go with smaller holes, but I am finding that the 3D printing process has limitations… Also, in order to keep the flow impedance extremely low (in the region below my measurable scale), you are going to need a total combined flow area to be much higher than the area inside the horn. This is because even having the same flow area, the drag coefficient goes up when the holes get so small. I can explain more if needed. In my design I have several times the “exhaust flow area” as compared to the flow area inside the exhaust hose, or the horn, or valve. In all the videos I have, my exhaust only uses less than a third of the holes even during the peak exhalation cycle. My hole pattern uses 999 holes (nothing magical about that number, just the pattern) and the separation is at least one diameter apart. I don’t want to discourage you from trying, but I don’t think you are going to be able to accomplish the same thing on a Trieste or even on a US Divers can. There is just not enough surface area on the cylindrical section. You could try putting the holes on the flat area, but that can be blocked by the divers back. At least I like it when my regulator is touching my back. It breathes the best... You could add a high spot in the center, just make it comfortable for the divers back. The sloped surface area in my Argonaut cans was barely enough area. I would have liked to add more separation between the holes.
The other thing that I am having trouble is with the quality of some of the commercial printer that I have being using. The cans look great, but holes that small seem to be very hard to be consistent. I have bought some extremely small drill bit that I use to clean the holes. It is a lot of fun to clean 999 holes… I probably missed a few... About the performance of my silencer: I do not have a hydrophone or recording lab instrumentation to do some proper measuring and testing. I have talked an acoustic engineer that has worked on similar projects. I could spend a minimum of $300 on instrumentation, but since this is just a hobby for me, it is not in my budget. All I have is my personal observations, which are very inaccurate (humans are the worst instrumentation) and recordings from my camera. Note: any video taken by another diver, what you are hearing is the exhaust of the diver behind the camera. I have taken videos where there are no other divers near me (I am the diver behind the camera) and in the recording, my exhalation sound is much lower than my inhalation sound. An issue with any video recording is that modern digital cameras are normally design to record the sound, so they must likely, will automatically adjust the recording level. They are not an acoustic lab instrument. One last thing the acoustic engineer warned me about, is the sound can conduct through the diver better than through the water. We hear our own bubbles more than we can hear other divers bubbles and the camera in our hands pick-up our own sound. I would like to think that any reduction in noise is better when approaching marine live, but as a minimum, I can say that it is more comfortable to me. The exhaust is quieter than the inhalation. During these deep dives I had to switch gases several time (travel gas Tmx 20/20, Deco gas Nx32, and 100% O2). Only my bottom gas was using the double hose, but during gas switches we momentarily switched to the bottom gas while stowing the previous single hose regulator. So, I got a lot of back-to-back comparison of performance and noise level. The performance was similar, but the feel and the noise difference was dramatic. Disclaimer: I am not an acoustics engineer (or stayed at a Holiday Inn Express) … James, I hope this helps, but, if you have any questions, please give me a call, we haven’t talk in a while.
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Post by Aquala1 on Jan 14, 2023 22:21:18 GMT -8
You can see my bubbles in the video. They start as tiny bubbles, but they grow fast as they move away and then sometimes reform into bigger bubbles about 3 feet or more away from me. When they get that far away there is no noise. Most of the time the tiny bubbles just continue growing as they rise. Here is a picture of the inside of one of the cans. I think the lighter color can. The filler material I used is clear so you can see a lot of the 3D printed imperfections. But the final surface that clamps the diaphragm is all filled in and is sanded smooth. I re-designed the exhaust valve to have a much wider landing to make it easier to fill and sand into a very smooth sealing surface. I also tilted the valve surface down 2 more degrees (away from the diaphragm) than before, and you can see the diaphragm stops. The exhaust support spider is also different. I am also having to use a sealer on the tube and sand that smooth. The tiny holes look a lot bigger than they are because the 3D printing doesn’t do sharp edges. And I have to clean many of them with a tiny drill bit. An interesting issue: the black can on the left is the last 3D printed can I will work on black. The material is so incredibly shiny and dark that it is very hard see what I am doing. I like the one on the right the best, but I have not head back from the vendor that produced that can. It has been over a year since the last time I was actually working on these cans and this project. I have two more printed cans that I put aside for a while, but I need to finish sanding and finishing them. It is not a lot of work, but I have to put time to do it. The other huge improvement (IMHO) is my new DSV flow diverter and the amount of venturi assistance I am able to adjust into my HPR second stage... stay tuned... Luis, in reading back through this thread, and your above discussion of the exhaust, you mention the “diaphragm stops”. Is the purpose of the stops to keep the diaphragm from coming into contact with the exhaust mushroom valve? I’m asking this because I recall in another of your posts, you saying that the Argonaut Kraken was designed to live forever and that if the plastic cans/boxes ever became damaged beyond use, the whole thing could be housed in a set of DA Aquamaster cans. My cans did become damaged, so I had my Kraken put into a set of DA cans and this was before knowing that this was something you all considered when designing the Kraken. Anyway, we used a duckbill eliminator and on a dive last summer, around 100 feet, the whole double hose part of the reg locked up and wasn’t breathable. Fortunately I remained calm and switched to my back up single hose. I stayed on single hose throughout the dive, occasionally trying the double hose and finally toward the end, it freed itself and I could breathe it again. Was this because the diaphragm and the exhaust mushroom came in contact with one another and stuck, not allowing the inhalation diaphragm to move? Is that why you have “diaphragm stops” on your integrated exhaust?
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Post by SeaRat on Jan 14, 2023 23:26:56 GMT -8
Ty,
As I have posted here before, I had this happen with a Healthways Scuba regulator (second generation) when I removed the mouthpiece mushroom valves and updated the regulator with a silicone diaphragm. What I found was that the removal of the mouthpiece non-returns allowed a back pressure against the diaphragm, which pushed it out against the exhaust mushroom in the box. I was not able to get any exhalation at all. The inhalation worked, but not the exhalation, and I had to terminate the dive and change regulators. I glued a stainless steel nut to the outer area alongside the exhaust mushroom, and that solved the problem.
John
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banana
Regular Diver
Posts: 18
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Post by banana on Jan 15, 2023 8:41:09 GMT -8
Luis, How are things going with the flow diverters? I am at the point where I have adjusted my Phoenix to where only 1/2 of a hole is open. This is made a big difference to me as far as ease of breathing goes, but I am starting to worry about blow-by at the DSV mouthpiece. Things are already a little wild as I bob around on the surface after a dive before engaging the dsv. On another note: I am very interested in your noise project. I have been musing on how and where exhalation noise is generated. I am wondering if larger holes with greater separation would more effectively suppress bubble recombination and the formation of larger bubbles outside the reg. Again I wonder what part of bubble formation generates noise? Take care.
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