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Post by hullscrubber on Dec 2, 2005 17:02:47 GMT -8
It sort of reminds me of the Daemon "mock" double-hose regs...... My local dive shop has one hanging on the wall I've been lusting after!
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Post by SeaRat on Dec 2, 2005 18:04:27 GMT -8
James,
That looks very interesting to me. I like the hose-within-a-hose concept as it provides a lot of air, and is less noisy (at least in the USD Overpressure Breathing rendition of the concept). By the way, this is not the same thing at all that the Demone regulator tried to be. That simply rerouted exhaust from the mouthpiece to somewhere around the shoulders on a single-hose regulator concept.
John
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Post by swimjim on Dec 2, 2005 18:57:36 GMT -8
If you use counter rotating propellers that would increase thrust and take the strain off of VintageDiverMN's neck. Then you can rock without the roll.
Jim
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Post by SeaRat on Dec 2, 2005 20:39:22 GMT -8
If you use counter rotating propellers that would increase thrust and take the strain off of VintageDiverMN's neck. Then you can rock without the roll. Jim I used to fly in the HH-43B Huskie helicopter: www.wpafb.af.mil/museum/modern_flight/mf19.htmCounter-rotating propellers are fine, as long as you don't hit something with one, as they rapidly then become out-of-synch. Fred Roberts, Basic Scuba, page 93 and 95-97 That was longer than I anticipated, but Fred Roberts did go through a detailed explaination of the pilot tilt valve, which I had not read before. I like Nemrod's ideas for the double hose regulator, and think they should be tested. John
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Post by VintageDiverMN on Dec 3, 2005 8:55:49 GMT -8
Hey Nemrod, I hear that the great Yankee Corps of Engineers will be using cotton bales to rebuild the levees around New Orleans. Us Yanks still have to punish you Rebs for beating us at Bull Run.
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Post by VintageDiverMN on Dec 3, 2005 9:10:19 GMT -8
Hey SeaRat, my brother was a flight mechanic on the H-43 in Vietnam. In Air Rescue.
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Post by SeaRat on Dec 3, 2005 9:50:31 GMT -8
VintageDiverMN, I was in the 37th Aerospace Rescue and Recovery Squadron in DaNang, and flew on HH-53C Super Jollies. I did serve a TDY to Thialand, where I flew HH-43 for a little time. My real experience with the HH-43 Huskie was in Korea in 1969. While in Korea, we tested some diving concepts. I had an NCOIC who was a bit ignorant of cold water effects, and he wanted to prove out the use of a survival suit (basically a dry suit) over his flight suit for water rescues. I told him it wouldn't work, but he insisted. So we set up a little demonstration, and he jumped into a reservoir near Kunsan, Korea in winter (February, I think). We let him sit in the water, and picked him up in about 15 minutes. He could hardly move, he was so cold. So we went back to our wet suits for rescue. I showed them how to make wet suits work (we had brought ours from Okinawa, which is a bit different environment). Oregon diving does teach people a bit about cold water. Your brother should enjoy this photo: Ask him sometime if he has heard of Bill Pitsenbarger, who was a PJ on the HH-43B in Vietnam, and lost his life on a heroic rescue attempt. To read more about that, see: www.mishalov.com/Pitsenbarger.htmlBill's story is compelling reading. From a vintage diving aspect, scroll down and see him in parascuab gear, in the doorway of a HU-16B Albatross amphibian rescue aircraft. He's wearing a wet suit, parascuba gear which includes an old USD Calypso regulator, and USD Aqualung Professional fins. I know this was an Albatross, as it had the shortest door in the USAF inventory for jumping. You either squatted in it like Bill is doing, or put one foot on the door's hatch and threw yourself out. I used the second way of jumping, but you had to duck low to keep your parachute from hitting the top of the hatch. By the way, your brother should be aware of the Pedro Rescue Association: pedroafrescue.org/goodfellow/goodfellowrestoration1.htmMy hat is always off to the FEs on any of the helicopters. They were never meant to fly, and keeping them in the air was quite a job. The funniest memory I have of our FE, SSgt. Draper, was when he went into the tail pipe of the Huskie to do an inspection of the back of the jet engine. He had to crawl up this pipe (see the photo), and he forgot to take off his belt, with it's metal USAF-issue buckle. Well, he scraped it on the pipe as he was crawling, and it sparked. Now the jet engines are fueled with JP4, and there is always a bit of residual vapor in the pipe. SSgt. Draper said he say a blue flame on the bottom of the pipe travel past his nose, and up into the jet engine. The next thing he knew, he was sitting on the ground behind the helicopter. The explosion had "spit him out" of the tail pipe. 'No injury, other than his ego. Enjoy, John
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Buzz
Senior Diver
Posts: 64
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Post by Buzz on Dec 5, 2005 14:19:56 GMT -8
Nemrod
Those are all the sort of things we want to try out to see if they will make a good contribution to the ease of breathing and user friendliness. At the end of the day (thats the British in me coming out), I hope the final design will breath so well that you wont even notice that it is there. I'm hoping that the servo (pilot) 2nd stage built into the cans along with the adjustable overbalance will accomplish this without having to resort to complicated add-ons.
Buzz
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Post by luis on Dec 5, 2005 17:39:38 GMT -8
I like some of the pilot valve ideas (I actually own a couple of Scubapro D400’s). The use of two diaphragms is kind of unique. As far as I know all other pilot valve regulators use one diaphragm to actuate the pilot / pneumatic force amplifier, which in turns it actuates the main demand valve (the Poseidon, Scubapro, and Techna are all like that). Having two separate diaphragms opens some interesting possibilities.
The hose inside the hose would probably have to contain as its static pressure the intermediate pressure. The drop in the intermediate pressure would be your signal (or actuator force) to the primary valve.
The main problem (about locating the pilot valve in the mouthpiece) is that in the swimming position the static pressure in the mouthpiece (the pressure when there is no inhalation suction or exhalation flow) of a vintage double hose regulator is close to the exhaling valve pressure. In other words the pressure is several inches of water column lower inside than the pressure of the water surrounding the mouthpiece. If you have a diaphragm in the mouthpiece it would be activated by the difference in the column of air inside the hose versus the column of water outside (unless you add some counteracting spring force and then you would lose your sensitivity in other diver positions).
There are a couple of other ways to handle the pressure differential. One method is to use a flooded exhaust hose. This is similar to the Demone regulator exhaust. A second method is to use an exhaust valve that will add back pressure equal to the column of water encountered from the mouth piece to the exhaust outlet. This solution can get complicated in order to work in all diving orientation.
Using the pilot / pneumatic force amplifier in the main housing with a well tuned venturi flow assist may be a good combination.
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Post by nemrod on Dec 6, 2005 1:04:17 GMT -8
I am sorry for posting again, I hope that folks do not become angry at me for doing so. I spoke to Luis via telephone the other day and we talked some about various concepts and thus this additional post. I think we are just interested in ideas even if they never become reality, it is fun to think of new things.
I fully understand and agree that a simple design based on as many off the shelf components is the most practical. I was simply trhowing out some other ideas.
So, I have presented essentially three concepts though I did not much talk about number three and alos number four I did not mention at all.
1. I suggested a pilot valve servo operated system all contained in the can, no mouthpiece diaphram, sense/balance tube or any other complication.
2. I suggested a unique double diaprham concept using a balance tube at IP pressure to trigger a powerful venturi effect to help the divers inhalation efforts to deploy the main diaphram. This method, as Luis rightly states, is not fully mature and would require some sort of counter balance spring or similar concept either in the mouthpiece or the main can to compensate for the water column difference between the mouthpiece diaphram and main diaphram.
3. Similar to number two but in this one I use a spool valve in the can triggered by the diaphram in the mouthpiece servo valve to mechanically assist/move the main diaphram downward agaisnt the lever system spring forces. It would only be powered downeard, spring force in the lever system returns the main diaphram to neutral and the spool valve being open to ambient in the can and using a balance spring to counter act IP is deployed only when the balance tune sees a drop in pressure (in the balance tube) caused by flow at the servo valve in the mouthpiece.
4. OK, here is another, this double hose has no main diaphram, the box/can is very small and compact. The mouthpiece servo valve and mini diaphram links to the main pressure valve again via a sense tube, 1/8 inch urethane etc, and when the servo valve actuates dropping pressure in the balance tube the main valve is actuated in the can and it's flow is directed by a vane into the inhalation hose. The exhalation hose empties exhausted air into the left side of the can--a seperate chamber filled with seawater just like all double hose regs---via two large mushroom valves. Since the can has no diaphram at all the valve here could be isolated in the can well off center allowing plenty of room in the flooded chamber for large exhaust valves. It would be about the size of a Trieste can.
There is the perception out there, right or wrong, that double hose regulators breath hard. Obviously most of us do not agree with that and all three of my RAMs could put up a good showing against modern rigs I am sure---but---there is the perception. The WOB may not be much worse than a single hose--the total breathing cycle--- but the initial effort required puts some divers off. I think other than complicated lever systems, all silicone valves and diaphrams, and a few things such as reducing friction of the levers and larger internal passage ways the current RAM design is limited in performance growth potential. I think the only way to make a double hose actually outperform a single hose is with some type of servo system. For a modern double hose to bring in non traditional users into the fold it must not only equal or approximate but OUTPERFORM all single hose regulators. Perhaps it is possible but not practical to accomplish that--that is for others more knowledgeable in manufacturing processes than me to decide. James
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Buzz
Senior Diver
Posts: 64
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Post by Buzz on Dec 6, 2005 6:40:57 GMT -8
Nemrod, Love your ideas......you and I think a lot alike. Hopefully on this project, there will be plenty of time to explore a lot of these types of ideas. Having developed servo valve operated tools for oilfield use, I have become a big fan as to their effectiveness. A few years ago, I developed a 2 stage pilot for a downhole transmitter that I had trmendous success with. One thing I would like to try is designing a 2 stage pilot for this project. Counting the balanced first stage, this would give the project reg a total of three true stages.. Hopefully, if this works like my downhole transmitter, there will be no negative consequences such as delay or lag time to get the main valve open. I have great confidence that this will be the case. However, I think the first design will probably not contain this feature.....only the hooks to put it in later. The reason for this exclusion is that I know I must develop the single pilot first and discover all the pneumatic orfice dimensions first before I throw in a second level of complexity. This is a lesson I learned on my downhole transmitter the hard way. Anyway, with all the great ideas we have seen so far....its really going to be a task to develop a game plan to incorporate as moch of this as we can into the project. With everyone's patience, I think we'll end up with quite a nice design or designs (whatever the case may be) Buzz
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Post by nemrod on Dec 6, 2005 11:14:23 GMT -8
Hey Buzz, playing the Devils Advocate here now--lol. One of the reasons that I think servo designs have not faired well or had wide acceptance is that their force imput/air output does not mimic well the needs of the biologic system to which it is attached. What do I mean? Well, back to he design I am most familiar with, the Tekna, when diving these there is a typical initial resistence to the breathing (as the tilt valve is tilted) then there is a hesitation (as the pressure drops in the servo chamber enough to offset the main supply valve mechanism) this causes the diver to subconciously increase his/her demand and THEN there is the sudden rush of air, rather forcefull and harsh, too much air!!! This causes the diver to reduce his demand (the rate at which he is expanding his chest diaphram muscles) and this reduction then results in a bootstraping effect where the regulator is out of phase with the divers demands. This is essentially what caused the stuttering and jumpiness in the Tekna, back pressure from the diver and a lower demand from the diver than which the regulator is wanting to supplyi. What I am saying is that any design, I am sure even this applies to the very first equipment, several modifications would have to occur before one is satisfied. I think that non-servo designs are more easily matched to human facotrs. Back in the day, you whippersnappers, I used to run marathons and triatlhons and was exceedingly fit. It is true that a fit diver consumes very little air at low work efforts, however, the other side is that a fit diver's human engine can consume prodigious amounts of air at high effort due to the extended levels of human performance when physically fit. My fascination with the Tekna began at that time because it was the only regulator that I had come across that could provide me all the air I needed at a sustained high effort--even if it was a fact that at low efforts and shallow depth the Tekna would not breath smoothly. Where was I going in such a hurry, well, some divers see diving as a hobby perhaps to relax and take it easy, some see it as a sport involving a certain athleticism, at that time I was the latter. Time changes such things as that but nonetheless, some people/divers can be very--uh--demanding!!! (that is a sort of pun). James
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Post by mossback on Dec 6, 2005 14:41:04 GMT -8
James
I agree with your summation of the Tekna, for others, try swiming against the current at Palancar reef at Cozumel or other places and towing your 12 year old to boot..that is just normal activity for a mid aged man diving who is not an athlete.....the Tekna never can be over breathed. I love mine just for that reason........I used a USD Gulf once in the flower gardens, after chasing after a large turtle for photos, I could not catch my breath with that reg unless I floated inverted....(pressure difference). The GULF was easy to over breath.
The Tekna does stutter tho in less than 10 feet of water, at least for me it does........not a problem...........
it'd be nice if a tilt valve like that could be incorporated into a double hoser..........but wouldn't the volume have to be greater down the inhale hose than what the tekna generates from its second stage? I wonder if that much volume of air traveling down that long hose would create some unforseen issues? Vs the short minimal distance from the Tekna's second stage.
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Post by duckbill on Dec 6, 2005 23:43:45 GMT -8
Isn't the tube-within-a-tube servo idea basically a single hose regulator within a double hose? What's the point of having both? This is starting to sound like a artists conception of how single-hosers might have evolved from double hosers.
As long as the mouthpiece is in your mouth and everything is static, the pressure outside the main diaphragm will be the same as the pressure at the inner surface of the main diaphragm, as well as at your mouth and servo unit. Water column would have nothing to do with it until the mouthpiece is removed.
Forgive me if I'm misunderstanding something here- The thread is getting longer than my memory!
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Post by nemrod on Dec 7, 2005 0:54:01 GMT -8
"Isn't the tube-within-a-tube servo idea basically a single hose regulator within a double hose? What's the point of having both? This is starting to sound like a artists conception of how single-hosers might have evolved from double hosers"
Not really. A single hose regulator has a hose of about 3/8ID or larger and the air that the diver breaths obviously travels in that hose. The concept I am giving uses a much smaller 1/16 to 1/8 diamter hose to interconnect the pilot chamber and main pressure chamber to communicate a pressure difference. Very little of the air the diver would breath would come from the very small inner hose. Also, USD did have the overpresure design which has already used a hose in hose but in a different way. SeaRat has experimented with them several times. I think what you are missing is that the small hose is not for air delievery--it is way to small, it is only for transfer of pressure signal. If you don't like the concepts that is fine, as I said, the question was asked for new ideas, these are mine, what are yours? I never said these were better, best or anything like that. I give up trying to explain this difference or it's possible advantages and problems.
The Flower Gardens are an interesting site aren't they Mossback. The turtles and other creatures there seem so out of place on the Texas coast. Very unusual place.
James
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