cg43
Senior Diver
Posts: 90
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Post by cg43 on Aug 17, 2023 12:16:58 GMT -8
Hello Duramax
For me Luis writes : You can use both . 70 and 90 durometer are good . I agree . Greetings Rainer
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Post by Fibonacci on Aug 17, 2023 18:30:48 GMT -8
Fibonacci, I think you may have found that at least some of the issue may be with the Trident seats. I hope so. Possibly adding to the problem could be the backup ring (item 6 in the Kraken schematic). In 1980 Aqualung replaced the -06 size backup with a smaller -05 size to help stabilize the HP seat. Since that date I have always used the -05 split Teflon ring in Aqualung and Mares regulators. Continue to use the -006 oring over the Teflon backup.
I recommend that change along with only using the blue Aqualung seat... I never had a problem with that combination. Thanks for the info... I hope so too, as I said before I enjoy diving the Kraken but it has now failed twice, once at 20m when literally the day before I had taken it to 36m... not keen for a repeat event! First total exhaust hose flood was on a night dive in remote PNG, rather unnerving Two out of the three major Kraken issues have now been sorted out as outlined earlier... but this last failure mode is obviously the most critical and what we need to stay focused on. Do you think they changed the backup ring specification to a smaller -005 size to grip the HP Seat stem more tightly and reduce any tendency for it to cant and produce the off-centre engraving... which can go horseshoe shaped in extreme circumstances? Or to help reduce HP leaks via the stem and lead to IP drift? My newly serviced Kraken with Blue AL HP seat locked up solidly and IP stayed stable for hours and then overnight. It was fitted with a 90 Duro -006 o-ring and backup ring. IP gauge showed it snapping back to 135psi without any drift at all... so far so good. But it needs a dynamic test to accurately simulate actual diving conditions before I feel confident to take it on any 'serious' dives.
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Post by vance on Aug 17, 2023 19:06:34 GMT -8
I wonder if the old style PITA to replace the o'ring balance block without the teflon backup ring would solve this problem or at least help by stabilizing the HP poppet?
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Post by antique diver on Aug 17, 2023 20:13:31 GMT -8
Fibonacci, I think you may have found that at least some of the issue may be with the Trident seats. I hope so. Possibly adding to the problem could be the backup ring (item 6 in the Kraken schematic). In 1980 Aqualung replaced the -06 size backup with a smaller -05 size to help stabilize the HP seat. Since that date I have always used the -05 split Teflon ring in Aqualung and Mares regulators. Continue to use the -006 oring over the Teflon backup. I recommend that change along with only using the blue Aqualung seat... I never had a problem with that combination. Thanks for the info... I hope so too, as I said before I enjoy diving the Kraken but it has now failed twice, once at 20m when literally the day before I had taken it to 36m... not keen for a repeat event! First total exhaust hose flood was on a night dive in remote PNG, rather unnerving Two out of the three major Kraken issues have now been sorted out as outlined earlier... but this last failure mode is obviously the most critical and what we need to stay focused on. Do you think they changed the backup ring specification to a smaller -005 size to grip the HP Seat stem more tightly and reduce any tendency for it to cant and produce the off-centre engraving... which can go horseshoe shaped in extreme circumstances? Or to help reduce HP leaks via the stem and lead to IP drift? My newly serviced Kraken with Blue AL HP seat locked up solidly and IP stayed stable for hours and then overnight. It was fitted with a 90 Duro -006 o-ring and backup ring. IP gauge showed it snapping back to 135psi without any drift at all... so far so good. But it needs a dynamic test to accurately simulate actual diving conditions before I feel confident to take it on any 'serious' dives. I never found the reason for the backup ring change since they gave no explanation in the bulletin, but it seems likely to have been to stabilize the HP seat. I don't recall ever having an issue with the oring sealing so I doubt that was the reason. They did have a bit of seat failures with the original thin black rubber sealing surfaces, as did Mares. I understand your reluctance to rely on the regulator at this time. I always keep a spare hp seat in my kit, and suggest that to keep from ruining a dive trip. Keep us posted.
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cg43
Senior Diver
Posts: 90
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Post by cg43 on Aug 20, 2023 0:52:59 GMT -8
Hello Antique diver writes: "I never found the reason for the backup ring change since they gave no explanation in the bulletin, but it seems likely to have been to stabilize the HP seat. I don't recall ever having an issue with the oring sealing so I doubt that was the reason. They did have a bit of seat failures with the original thin black rubber sealing surfaces, as did Mares." On the CG45 side I found a drawing from the old CG45 The HP seat is very interresting . Why did the french colleg's did it this way ? Greetings Rainer
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Post by antique diver on Aug 20, 2023 8:15:44 GMT -8
I wonder if the old style PITA to replace the o'ring balance block without the teflon backup ring would solve this problem or at least help by stabilizing the HP poppet? Phil, good point. It might if the poppet stem was an appropriate fit in the block. Worth a try.
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Post by spirou on Aug 20, 2023 9:50:26 GMT -8
Hello Antique diver writes: "I never found the reason for the backup ring change since they gave no explanation in the bulletin, but it seems likely to have been to stabilize the HP seat. I don't recall ever having an issue with the oring sealing so I doubt that was the reason. They did have a bit of seat failures with the original thin black rubber sealing surfaces, as did Mares." On the CG45 side I found a drawing from the old CG45 The HP seat is very interresting . Why did the french colleg's did it this way ? Greetings Rainer Hello, In fact with regard to the CG45, we should not speak of "the colleagues" but of the "CREATOR", we can consider that there is only one person behind this regulator with regard to its design, it is Emile Gagnan. Note that the diameter of the membrane membrane has remained the same until today on the regulators of the aqualung brand and other brands (nowadays this membrane is thinner). Concerning the valve of the CG45, we are in France, at the end of the war, the country is rebuilt. The O-ring seal is not yet available in France. Emile Gagnan will build something robust, simple and reliable. the aquamaster which is an evolution of the CG45 which will be very appreciated by the US navy, there is no oring on this regulator, only flat seals. ( first stage non compensate) The oring seal will become on diving regulators with the single-hose regulators. The very first piston regulators will experience problems because the adjustment tolerances are much lower Respectfully. Fred
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cg43
Senior Diver
Posts: 90
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Post by cg43 on Aug 20, 2023 14:16:19 GMT -8
Hello Fred
O rings and kompensated first stages are not my topic . I whished you to look for the great HP seat . "Sorry for this shall I say missunderständing". What you can see in the drawing is that the gasket , let's call rubber , is a long zylinder , not a thin plate like nowadays . The reason for this is to reduce material tension . Let's be: sigma = material tension E = elastizitätsmodul ( that depends on the material) delta L = waylengs the rubber is deformed Lo = thickness or length of the rubberzylinder
Now we have the the formula : sigma = E * delta L / Lo
Choosing a bigger Lo you can reduce sigma or use a material with highter E and strenght . Becaus the rubber looks to be enclosed it's more complicated then the simpel formular shows . I don't know if this Attempt was very succesfull .
If you see this in the drawing you are a colleague of Mr. Gagnan .
Greetings Rainer
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Post by vance on Aug 20, 2023 15:21:03 GMT -8
Rainer,
It is somewhat difficult to understand your post. I do not wish or mean to criticize anyone who can communicate in a second (3rd, 4th, etc.) language. Please accept that you have my admiration. I have difficulty making myself understood in my native language!
There are some clarity issues, and I hope I haven't misunderstood your point.
I believe you are trying to say that the CG-45 had a different HP poppet design than was used in later models. Having never seen a CG-45 poppet, I can't say for certain whether this is true or not.
However, it appears from the diagram that the assembly is much like (or exactly like) any HP assembly found in unbalanced 2 stage USD DH regulators up to and including DAAMs, excluding the one piece HP spring retainer. That was also found in Spacos and the earliest Broxtons, however.
The HP pin contacts and actuates the HP poppet via a thin brass post left in the center of the poppet after machining a deep circular groove around it. This groove accepts a nylon (or some sort of soft material) cylindrical seat insert that is pressed in to surround the brass center post. (This is also how the soft seat was fitted into brass USD single stage HP seats.)
The insert is thicker than the flat soft surface found on balanced HP poppets. I suppose the formula you cite might explain why they chose to do it the way they did, and I'll accept it without question. However, I'm pretty sure it was done that way for simplicity and practical purposes such as making sure the soft seat didn't fall out.
If the CG-45 poppet is substantially different than my description, I'd love to see a photo of one. However, if it is essentially (or exactly) the same, the question about the design's success is, well.....unquestionable?
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cg43
Senior Diver
Posts: 90
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Post by cg43 on Aug 21, 2023 4:35:23 GMT -8
Hello vance
You write :"It is somewhat difficult to understand your post."
Right , I wrote to much between the lines . I'm an european and like to do it this way , sorry. And rigth , I'm not lucky with the Aqua Lung type HP seat . It could be build more robust . If all went well , shure it is strong anough but littel faults can grow up quick . I will accept a littel freeflow , but not a big one . If that occurs it's time to change something .
Go to the Aqua Lung people and ask them: "If I give you 5mm more in length of the seat , can you make it more robust ?" An technican may answer : Shure , but our heaquater had to agree and that's not an easy task .
You write:"The insert is thicker than the flat soft surface found on balanced HP poppets. I suppose the formula you cite might explain why they chose to do it the way they did, and I'll accept it without question. However, I'm pretty sure it was done that way for simplicity and practical purposes such as making sure the soft seat didn't fall out."
You may be rigth , I don't know . I never had a CG45 , drawings or something else like internal information.
I write:"Choosing a bigger Lo you can reduce sigma or use a material with highter E and strenght .
Becaus the rubber looks to be enclosed it's more complicated then the simpel formular shows .
I don't know if this Attempt was very succesfull ." This only belongs to the attempt to reduce material tension , not the hole CG45 .
Greetings Rainer
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Post by vance on Aug 21, 2023 8:03:17 GMT -8
I was referring to the success of the HP poppet, if it is the same design used in all of the USD 2 stage unbalanced DH regulators after the CG-45. We still need confirmation that the CG-45 HP poppet is similar or not, but it sure looks like it from the diagram.
BTW, an almost identical poppet is used in the Nemrod DH regs. It's very difficult to tell if one is a Nemrod or USD by eye.
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Post by SeaRat on Aug 21, 2023 8:07:28 GMT -8
I have a DA Aqualung regulator, and I believe that the first stage of the DA Aqualung is exactly the same and the first stage of the DA Aquamaster. It is only the second stage, and the orientation, that changes in this regulator line. The CG 45 is the predicessor of the DA Aqualung, and probably has the same first stage too.
At the time of manufacture, 1943 to 1945, as cg43 says above, there was not the technology to use O-rings interior to the regulator. The evolution of the Aquamaster continued, and the first stage stayed the same until the Royal Aquamaster came along, which I believe is the first to have a balanced first stage with O-rings internal to the first stage. (This is from the AQUA-LUNG Repair Manual, June 1, 1971.)
BUt getting back to the OP, I don't see where this discussion of the original Aqualung and the evolution to the Aquamaster has much to do with the Kraken. It seems that the Kraken evolved from U.S. Divers and Aqualung single stage hose first stages, and not the original double hose regulators.
John
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Post by spirou on Aug 21, 2023 8:11:03 GMT -8
Hello Rainer, Phil, and John
I am on this forum first of all for fun and to share with humor.
I apologize if you didn't appreciate my comment Rainer.
I had noted the difference with regard to the thickness of the nylon, (hence the reduction in tension) and which greatly influences the holding of the valve, and therefore its performance and its holding over time.
I respectfully allow myself, with the information I have, to confirm that the first stage of the CG45 is strictly identical to the BROXTON, and so on.
In what follows I respectfully allow myself to propose a hypothesis. When the US Diver balanced valve appeared (not the first calypso), it had to be integrated into an aquamaster, there was a first model, the royalmaster, which had extrusion problems, hence modification which gives the couple spingblock with anti-extrusion seal and valve, on the RAM.
This couple springblock valve princip is used on many models. AL, Les Conshelf, TITAN, CRESSI MC5, MC9, Mares MR12, others.
The blue Aqualung model is the subject of a patented it was introduced on the TITAN, The TITANs which started to be used were marked with the patented number. MARES did the same with its seats, which are very close to the Aqualung, the Cressi on the MC5 and MC9 is different
I have several regulators with blue Aqualung seats with which I have a lot of dives and I therefore have a lot of questions about what I read here.
I will try to find pictures of the valves and put them here
Respectfully
Fred
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cg43
Senior Diver
Posts: 90
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Post by cg43 on Aug 21, 2023 15:03:08 GMT -8
Hello Fred
We don't need to have the same view on a topic . I will find it more interesting to read the opposite , especially if it is based on facts that are new for me . And you knew a lot about this valves and regs. that I don't knew . Up to now , I see no reason for both of us to apologise and I am sure this will last on . Let us diver be colleagues .
Greetings Rainer
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Post by vance on Aug 21, 2023 16:22:26 GMT -8
BUt getting back to the OP, I don't see where this discussion of the original Aqualung and the evolution to the Aquamaster has much to do with the Kraken. It seems that the Kraken evolved from U.S. Divers and Aqualung single stage first stages, and not the original double hose regulators. John The discussion is relevant, since it concerns comparing and contrasting balanced and unbalanced HP poppets. HP seat failures can occur sooner to very quickly with later, balanced regs. There's also the catastrophic failures of Voit HP poppets which are similar to USD poppets. This has been discussed before, and it could be a materials issue. As we are discussing, p erhaps there are other tolerance problems with the Kraken that exacerbate the failure problem with a design that might have been better if it had not been changed? I think that Rainer is suggesting that a similar approach to the unbalanced poppet, with its deeper (thicker) cylindrical seat might have been a better way to make them. I don't know if tolerances would allow that, but the flat, thin surface of the later poppets has certainly led to failures.
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