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Post by scubadiverbob on Sept 22, 2007 22:21:20 GMT -8
Wow, this is a great discussion. I'm not clear on the "DSV" - Nemrod, can you explain the function, and need for this? Mouthpiece clamps - I thought clamps added to the appeal. I don't like hte ratcheting ones, I think they are less secure than clamps with screws. I'm not familiar with screw-on hoses. I'm also not familiar with the hose terminology - 1x1 and 15.x1 - can someone please explain? I guess much of this would depend on what this would sell for - but that's another poll, I guess! Thanks, keep it coming, please! jv 1" x 1" hoses are used on Dacor; 1" x 1.5" are used on USD regs. The inch designation is the ID (inside diameter) of the end of the hoses. USD hoses have 1.5" ID, on one end, to fit the wider mouth pieces and 1" to fit over the horns (I wish the 1" ID on one of the hoses were a little wider to fit the exhaust horn with the duckbill valve on it; but, they would cost more for a pair). Sometimes the size of the hoses might be shown as 1" x 1.5" x X' ("X" being a variable defining the length). Screw on hoses are on the New Mistral regs. The mouth piece screws off both ends to make it easier to dry the hoses. If you go to your LDS (Local Dive Store) ask them to show you a New Mistral reg. (regulator). This is the best I can explain answers to your questions. We do have some scuba instructors on the forum that might be better at explaining stuff. Maybe they can speak up. Robert
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jviss
Pro Diver
Posts: 209
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Post by jviss on Sept 23, 2007 10:35:31 GMT -8
This is a great discussion, I'm enjoying it. I am not familiar with regulator or valve technology, 'though I know a lot about seals. I'm a EE, but have done quite a bit of mechanical engineering in my career, too, as well as manufacturing engineering, quality, etc.
I just read the Mentor repair manual. I also looked at the flashback scuba museum page on the Mentor.
If have this right, not even the Mentor would satisfy Nemrod's requirements! I'm thinking of the externally adjustable IP in particular - and wondering why? On the Mentor, you pop the can, and turn an 8mm Allen wrench to adjust. Seems simple enough.
I was thinking, why not just clone the Mentor? It looks to my eye not unlike a DA, in fundamental design principle, except with the HP and LP ports, mushroom exhaust valve, minor design changes to the lever, etc., and a new mouthpiece. I like it. I like the simplicity.
But, I'm not a valve expert.
Another observation is that my DA has the adjustments staked, both the first and second stage adjustments. Neither are staked in the Mentor.
One part that puzzles me is the "adjustable crown." I guess that this is to allow external adjustment of the second stage, i.e., "cracking pressure," yet that adjustment is never mentioned in the manual, that I can find.
I understand Nemrod's interest in a more sophisticated mouthpiece, with a DSV (dive/surface valve?) - I don't understand the distinction between this and the "dive/pre-dive switch" - but perhpas this more sophisticated mouthpiece could be an option?
The DA with the Phoenix is pretty much functionally equivalent to a Mentor, except for the depth of the unit, and the external "adjustable nozzle" or adjustable crown, and the fact that on the Mentor the ports will always show up at the same place.
As for the quick clamps, m take is that these are "Herbie Clips," made by HCL (I guess the patent has expired!)- these are available for something like $0.25 if you search around, or if you're in a hurry, home Depot here in Massachusetts has them. But, you might have to buy 10 to get them for a quarter each. I don't care for them because they can be knocked off with a sideways blow.
I'd like to understand how you might implement a venturi or pilot boost.
Thanks,
jv
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Post by luis on Sept 23, 2007 12:12:02 GMT -8
"Popping" the can is a pain in the rear to adjust IP. The main improvement of the Mentor over the Phoenix RAM is the mushroom exhaust valve and the external adjustable IP. I just want to be able to reach back during the dive and turn a knob just like I do on my Legend to custom tune it to the needs of the moment. Luis does not like my pilot valve ideas. My interest there are to allow a much smaler can and thereby much smaller main diaphram and use the servio valve to boost response--just like the Tekna, Oceanic Omega and some ScubaPro designs and some Cyclons etc. James The Mentor IP is not externally adjustable; it is the same as a RAM. The external adjustment is the second stage volcano orifice. This will in turn adjust the second stage spring tension. I don’t dislike the pilot (pneumatically assisting) valve. I do feel it is an unnecessary complication when you can instead take advantage of the large mechanical advantage of a large diaphragm. There is a lot to be said for simplicity. I do like a balanced second stage, I feel it is a great improvement for a single hose regulator, but again in a double hose you can deal with a simple large diaphragm instead. The second stage sensing diaphragm (or pilot valve sensing diaphragm) need to be next to the exhaust anyway. Mechanically a RAM can be adjusted to ½ inWC cracking pressure or less. You can’t get much better than ½ inWC. Even if you could, you wouldn’t be able to tell the difference. Some of the breathing resistance we experience is from the differential water column and a bit from the mouthpiece valves. The venturi assist helps tremendously to assist in supply air once the flow is initiated (just compare an Aqua Master to an early Broxton). The venturi doesn’t help with the cracking pressure. The only way to truly solve the pressure differential in the water column is to use a positive pressure system, in which case you may need a full face mask or similar system. It would be more complicated that just using an Aqua Lung.
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Post by luis on Sept 23, 2007 12:24:24 GMT -8
The DA with the Phoenix is pretty much functionally equivalent to a Mentor, except for the depth of the unit, and the external "adjustable nozzle" or adjustable crown, and the fact that on the Mentor the ports will always show up at the same place. Thanks, jv According to Ryan, the Mentor and the Phoenix RAM are essentially the same height. The dimensions are very similar. I would like to redesign the RAM second stage to have an adjustable volcano orifice (crown) and a simpler lever support, similar to the Mentor. One advantage of the Phoenix over the Mentor is the number of ports. I think the Mentor only has one or maybe two LP ports. That is only a minor inconvenience since port adapters are easily available (I surely wouldn’t turn down a Mentor for this reason). When I dive in a drysuit I need 3 LP ports.
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jviss
Pro Diver
Posts: 209
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Post by jviss on Sept 23, 2007 14:38:18 GMT -8
By staking I meant the that after the first and second stage adjustments were made, a punch was used to distort the top of the thread junction to prevent it moving with vibration,etc.
On balanced first stages, perhaps I'm a bit confused. I recall from my reading years ago that "balanced" design referred to a feature that compensated for depth - that is, that the IP was pressure over ambient, not over 1 atmosphere where it was adjusted. Of course, a valve that featured a compensation for supply pressure could also be incorporated into a first as well. So, what feature does the balanced first of a RAM have? The over-balanced Legend is overbalanced regarding ambient pressure, i.e., depth, "at a rate that increases exponentially in relation to depth" according to Aqualung.
I'm sure I'm wrong, but examining my DA it appears that one side of the first stage is exposed to ambient, via the breathing box. So it would seem the IP is regulated per ambient pressure, not simply spring pressure. I suppose it isn't regulated per supply pressure, which I assume is the RAM's distinction. Is this so?
The Mentor IP (MP in their vernacular) isn't externally adjustable according to my read of the manual, only the second stage seat position - which is what I think the "adjustable nozzle," or "adjustable crown," although the adjustment isn't detailed in the manual. It's not a knob, it requires an Allen wrench.
I don't understand the need to adjsut the IP externally - how often would you have to do this?
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Post by luis on Sept 23, 2007 17:33:03 GMT -8
In the case of a regulator, a balanced first stage valve means that the mechanism will not be unbalanced by the changing tank pressure. The tank pressure does not affect the opening and closing of the regulator first stage valve. Therefore, the IP doesn't change with tank pressure.
You can also have a balanced second stage (at present only single hose regulator) were the effects of IP changes on the valve motion are minimized by having a balancing chamber. A second stage should never be totally balanced or it will not relieve excess intermediate pressure in the case of a first stage leak.
All scuba regulators are ambient pressure compensated. That is not the same as balanced. The IP will increase “with” ambient pressure. It is always the same amount of pressure “above ambient”.
This last section about “over-balance” has nothing to do with double hose regulators.
What Apeks (and now Aqua Lung, and some others) are calling over-balanced should be call IMO over-pressure (IP) compensated (or something like that). The IP increases “above ambient” proportionally with ambient pressure.
This only applies to environmentally sealed diaphragm regulator with a solid plunger pushing from the external environmental diaphragm to the intermediate pressure diaphragm. The effective area of the outer diaphragm is a bit higher than the inner diaphragm.
IMHO this is just a big sales gimmick (not the environmental seal, but the so called overbalanced). The high end regulators that include this overbalanced also include balanced second stages that are for the most part not affected by a change in IP. Also if you can adjust the IP higher at depth why have a lower IP when you are shallow. IMHO this was kind of a design accident. It was probably easier, for the designer, to have the outer diaphragm just a bit larger than the inner one, rather than trying to perfectly match the effective areas of two diaphragms with different stiffness. Then marketing decided to capitalize on a minor design flaw.
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jviss
Pro Diver
Posts: 209
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Post by jviss on Sept 23, 2007 19:47:04 GMT -8
Whether it be an "overbalanced" design or not (since we collectively don't seem to find the term for this feature) In my previous post I was quoting the Aqualung literature for the Legend - here's a more complete quote: "The over-balanced design is engineered in such a way that its intermediate pressure increases at a rate faster than ambient — so much so that by the time a diver gets to 165 fsw, it has actually picked up an additional 2 atmospheres (29.4 psi) of pressure! Notice how the gold line on the graph increases at a faster rate when you go deeper. This intermediate pressure boost defines true overbalanced first-stage technology. So what is the benefit of an over-balanced design? Air gets denser with depth. This thicker air moves more slowly and creates increased resistance as it moves through hoses and valves, decreasing the overall performance of the regulator. By having a higher pressure in the regulator hose, once the second stage opens, the air moves through more quickly, making the regulator more responsive and providing a real improvement in performance at depth."
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Post by SeaRat on Sept 23, 2007 20:49:44 GMT -8
Yeppers, that is what I was reading as well. In order to make full use of this feature (if it is a positive feature) there must be a tuning knob as on the AL Legend second stage. I want that knob placed on the side of the can where I can tune it on the fly. An average setting would be set uisng a detent in the mechanism so the diver could easily tell where the tuning knob is in it's travel by feel alone. Nemrod Nemrod, It sounds like you are also looking for a chest-mounted second stage (easily accessable knob...) (I know that Nemrod doesn't like things on his chest.) John
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Post by duckbill on Sept 23, 2007 21:17:29 GMT -8
How about just a user-installable and removeable exhaust insert for a mushroom valve? That way, the original AquaLung look and value can be retained, while providing the option for a mushroom exhaust valve.
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Creed
Pro Diver
Posts: 189
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Post by Creed on Sept 23, 2007 21:34:58 GMT -8
Well, I've got samples from a plastics company on my desk right now for making small run cast plastic products. I have a DAAM body that I am planning on putting a Phoenix nozzle in. I would like to make a 'Jet Air'-esque case to fit the DAAM body, and modify the case to use a mushroom valve for the exhaust. I like the screw on style of case better than the clamped style. I'll post any progress I make in this area.
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Post by Broxton Carol on Sept 24, 2007 0:33:25 GMT -8
If a regulator was ACTUALLY available with ALL those features you guys would still want more! Ill stick to my broXton. It might be caveman by modern standards, but for me its just fine !
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Post by luis on Sept 24, 2007 2:17:09 GMT -8
How about just a user-installable and removeable exhaust insert for a mushroom valve? That way, the original AquaLung look and value can be retained, while providing the option for a mushroom exhaust valve. I have been thinking about that for a wile. First decision: permanent modification or not. If it is permanent it could be brazed and then re-chromed. It would be a bent metal insert similar to what many other regulators (Healthways, Sportsways, and Nemrod, etc.) have incorporated. Not permanent, it could be bonded or it could be mechanically fastened using one screw hidden under the label. It could be a three sided bent metal piece or it might be easier if it was a more like a closed rectangular tube with the mushroom valve facing the diaphragm. In a removable insert the connection to the exhaust horn could be via a thin hose, or sealed with some caulking, or sticky back foam tape. In any case, if there is a small leak it wouldn’t be a problem since it the exhaust anyways. I am still thinking about it. When I have a chance I will start making some drawings. One I have it in paper (actually computer/ AutoCAD) with correct dimension, it will be easier to figure out what may work. Oh, and the mushroom valve doesn’t need to be very big. No need to make any bigger than the mouthpiece valves. If it is too big it could easily free flow since the top edge of the valve could be higher than the center of the diaphragm. The distance would be the radius of the valve, therefore the valve should never be much bigger than 1 inch (if you are going to fine tune the regulator to ½ inWC cracking pressure. The valve should be a modern silicone with the bent down edge.
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mudhog
Regular Diver
Posts: 18
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Post by mudhog on Sept 24, 2007 18:43:12 GMT -8
I would buy a updated Mentor.
I believe the cure for the freeflow proablem should be at the mouth piece, it's a wide spread proablem and it would be nice if the ansure would fit any double hose reg with 1 inch horns.
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Post by SeaRat on Sept 24, 2007 22:04:16 GMT -8
...I know y'all don't like some of my musing but sooner or later we are going ot electronic dive gear. Power FADEC controled integrated scuba. The pressure sensor could be located wherever you need it or want it, chest, wrist, mouth, top of your head--lol--wherever and it could be wireless or wired--for example--into the harness. The depth sensor would be piezo--not a diaphram and not mechanical. The system would be fully electronic activated pneumatic servo valves. Better have a good battery, well, like aircraft it will have dual channels and a third back up channel and back up battery in a canister integrated into the harness.---lol. Try that with your ol' double hose. By the end of the 21st century mechanical scuba gear will be archaic just like mechanical fuel control on aircraft--the world is a digital world now. I will settle for a mushroom valve. The duckbill works fine but it is maintenance intensive and not quite as efficient as a mushroom. Nemrod Nemrod, Concerning the mushroom valve, be careful what you wish for. The first mushroom on a Healthways Scuba regulator was terrible; the diaphragm came in and jammed it shut. You need a space between the diaphragm and the mushroom for it to function. They did that with the Gold Label Healthways Scuba, by placing a small metal fin next to the mushroom valve to keep the diaphragm from jamming it shut. On the Snark III, there are little bumps in the case which keep the diaphragm away from the mushroom. These are small refinements, but necessary. I did not see this on the Mentor, but probably they put enough space between the diaphragm and the mushroom to keep it from being jammed shut; either that, or they indented it a bit... My favorite exhalation valve is the original DA Aqualung, with the removable horn. This valve used a duckbill, but over the top of the horn on the inside, not inside the horn from the outside. It would wear very well. I have my original DA bottom box on my Mistral regulator, and really enjoy the duckbill in this configuration. I can use worn-out duckbill valves on this setup, and they stay there for years without a problem. They also lay correctly across the diaphragm, beyond the center point, and so there is no leakage from the valve as there is on my mushroom valves on my Nemrod Snark III and my Hydro Twin in some positions. This is what needs to be placed on the Phoenix Royal Aquamaster. Now, about your musings. You're not the only one. We all dream a little. John
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Post by Broxton Carol on Sept 25, 2007 7:36:26 GMT -8
I put one of Dans duckbills in my royal aquamaster 5 years ago, and it still works perfectly. My BroXton is 52 years old............. still has the original bill in it. Works just fine. Avoid tinkeritis! If its not broke, dont mess with it!
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