Project Argonaut, totally new, vintage style DH regulator

[Luis H]

A DH is going to freeflow at the surface if you get into the right position due to it's design, the single major flaw in it's design IMO but there is little you can do to prevent it- design wise. Add to that, all the upgrades that have been made and many of us tuning the regs to fairly high performance levels, freeflows become more of an issue. Proper technique reduces them a lot but having them prevented without having to be so vigilant would be nice. The plug does a good job but it's not as elegant of a solution as we would like so the next logical step is designing a mouthpiece that does the job of the plug but with a lot more elegance.

By the way, the tool also works on the Argonuat.

We should point out for those who are not familiar with a double hose, that this only happens when you take the mouthpiece out of your mouth and the mouthpiece is higher than the diaphragm. It is the same effect as when you take a well tuned single hose regulator out of your mouth with the mouthpiece pointing up.

It is all about the differential water pressure due to the water column. The same physics applies to all regulator, the only difference is that the distance from the diaphragm to the open mouthpiece can be much higher with a DH.

---------- Post added April 9th, 2014 at 08:01 PM ----------

The design for a closing DSV (Dive Surface Valve) style of mouthpiece with the ability of using a replaceable byte (single hose type mouthpiece) is in the works. It is just going to get a bit more time.

I have already designed and build a couple of different DSV type of mouthpieces, but I have a new design that reuses the same valve cages that we already have available.

The design is fairly simple, but I have to do a precise 3D model that we can have printed in a 3D printer.


This all takes time. I do all these designs just as a hobby.

Note: I actually don't build anything. Herman builds a lot of the prototype parts based on my drawings, but some of the more complicated parts Bryan (from VDH) has have a commercial machine shop make it. Bryan also has the molds made for the molded parts (he owns the molds).

---------- Post added April 9th, 2014 at 08:11 PM ----------

With regard to mouthpieces (I'm sure its been asked before), but why not reproduce the Hope-Page mouthpiece or some variant? I believe that it will take a modern replacement mouthpiece. And if not that, why not cast something like it in a hard plastic or bakelite into which wagon wheels would fit or on which you could mount a modern mouthpiece? Will all the fabricating that Luis and Bryan seem to be doing, I would think that a HP mouthpiece wouldn't be too difficult. Of course, I've never tried or priced such a thing and it may be just too expensive.

There has been some talk about making a Hope Page reproduction mouthpiece. I was asked if I would do the drawings. I agree, but then I pointed out that a true reproduction required at least three molded parts and the machined ring, the project went nowhere.

The three molded parts are: the main boy, the two hose connection (left and right are the same), and the valve wagon wheel cages (I think they are the same or I could make them the same mold).

That is three molds. Good quality production molds are expensive.


By reusing the existing mouthpiece valve wagon wheels, it would save some money.

 

[tplyons]

Wow, so disappointed I missed this. Subscribing for updates so I can jump on one when they become available

 

[Luis H]

Wow, so disappointed I missed this. Subscribing for updates so I can jump on one when they become available

They will be available. You just missed the initial offering, but the demand is growing and there will be more.
At this point in time, it is just a small company with some friends help him out. But he has a lot of support and a lot of friends.

I expect that more will be for sale in the fall. VDH just has to fill some orders this summer.

 

[John C. Ratliff]

Luis, has any consideration been given to providing longer hoses of the USD type (so as to be compatible with the new and existing mouthpieces), and having them be the super-flex hoses? I know that at one time these hoses were available (about ten years ago) as I got a pair. But if the longer hoses were available, it would allow the regulator to be dropped down further on the diver's back, right between the shoulder blades, without the restrictions of the USD standard hose length.

Concerning free-flow, this doesn't occur on the surface either if you replace the mouthpiece with a snorkel, and lay out a bit face-downward. This swings the regulator up toward the surface, and also moves the mouthpiece in relation to the body down into the water column. I don't consider the free-flow a design flaw, but rather a design characteristic that is at the heart of double hose usage. It makes clearing the mouthpiece underwater a cinch, and is easily controlled by body position in the water. With longer hoses (I have super flex hoses on my AMF Voit Trieste and several other regs with a Hope-Pape mouthpiece) you can also simply hold the mouthpiece down lower in the water to stop the free-flow.

Concerning the new mouthpiece, be sure that the design is such that accidental restriction of the air flow during a dive is difficult to have happen. Some sort of positive locking mechanism might be needed to ensure that inadvertent blockage cannot occur easily.

SeaRat

 

[Luis H]

I am not designing the hoses, but believe that Bryan is planning on offering a couple of different types in the near future.

The silicone hoses are working great for me. I can place the regulator exactly where I want it (between my shoulder blades) and the hoses are not pulling.

The silicone hoses are very flexible and very durable. Silicone hoses are commonly used now-a-days for re-breathers (I am fairly sure that even for all the Navy re-breathers).

I know that the hose length can be a bit of an issue for some very large divers, but I think the silicone hoses are flexible enough to accommodate most divers.

Added:
The silicone hoses also have the side benefit that they don't support bio-growth. They should still be rinsed and dried. Cleaning and drying is a lot easier with the rounded convolutions than with the sharp convolutions found in the old style super-flexible hoses. I have both kinds, but I only use the newer silicone hoses for every day dives.

Part of my design includes the option of using thumb screws on the horn hose-clamps for easy hose-loop removal, for rinsing and drying.



Thanks for the advice for the DSV design, but the is no need for a positive locking mechanism. I have enough actual experience diving, designing, building, and testing DSV mouthpiece, that I have narrowed down what I am planning on doing.

Non of the DSV used on re-breathers have a positive locking device. I have tried (demo dives) six different types of re-breathers with different DSV mouthpieces. I have also checked out a few others, including several military re-breathers (including modern Navy and some foreign vintage units).

 

[John C. Ratliff]

Luis,

I have played around a lot with hose length and different hoses. But with your improved venturi on the Argonaut, the flow will become almost effortless and the lowest possible position is not really necessary. It (the lowest position) was pretty critical for the Cousteau divers using the first generation CG regulator, due to the breathing characteristics of that regulator. I used my DA Aqualung regulator with a Hope-Page mouthpiece on original-length hoses (they were actually shorter than the now-stardard length), and it was tolerable for inhalation breathing, but not real fun--exhalation was great though. They continued to use it with their triple-tank setup when using the Mistral. Pictured is my Mistral with the super-flex hoses and the La Spiro Professional mouthpiece. This mouthpiece has very good performance characteristics, but most of today's divers won't like it as there are no non-return valves in the mouthpiece.

Luis mentioned above the sharp convolutions in the super-flex hoses. They can be a problem, just as he said, and bacterial/fungal growth is a problem. The bottle brush technique doesn't work too well with these hoses, but can be used if the hoses are pulled apart when the bottle brush goes through, rotating it as it passes through the hose. Drying is also a problem, and I've found that swinging these hoses in a vertical swing (outside, don't do this is your home ) removes most of the water. Those problems are not inherent in the new silicone hoses, according to Luis above--this is a great benefit.

The reason for mentioning the positive locking position on the mouthpiece block is that I used to work in product safety for a large semiconductor manufacturing firm, and these are considerations we were tasked to complete for these machines (fail-safe mechanisms for users).

SeaRat

 

[Nemrod]

I have been using, mostly for shore dives involving long surface swims where I prefer to swim on my back, a DSV made from a USD straight mouthpiece. It was an idea cooked up I do believe by Mr. Luis and in fact this particular one was given to me by him to experiment with.

It is a simple rotation from full closed to full open. I have never really needed to have a detent to remind me to open it or any reason really to close it underwater except for experimenting. During my surface swim the DSV is closed, when it is time to submerge, I open it. On my return swim, I close it, no big deal, pretty easy.

Anyways, after using it for several years, I just have not had any real issues with determining it's status, open or closed. I once was given a Craftsman flashlight that had a battery charge indicator, green for charged and red for discharged, like duh, could I not just turn it on and look and see if the light is on? That is sort of like my thinking on a detent. It seems like a good idea but in practice it it just not needed.

N

 

[Luis H]

I don't think that John realizes that there is enough friction that it will not just slide into a closed position. The design of all DSV that I have seen, function on a similar principle to a ball valve (or a rotating gate valve). Just by the fact that they have to seal, it provides enough friction that they are just not going to slide out position.

As I mentioned, It is a proven design used in true life support equipment.

 

[John C. Ratliff]

Luis, you are correct in your assessment, but I was not thinking of it simply sliding into a closed position. I was thinking back to the U.S. Navy pool harassment, and what the instructors did to us to make the scuba non-functional. They did that to prepare us for when "stuff" happens. I was thinking more of the DSV mouthpiece being kicked by a fin, or a panicked diver trying to get at the air. When I think in these terms, I usually revert back to my military experiences; a jump from too high, for instance, or getting tangled in lines. There is a reason that purge valves on single hose regulators became flush with the cover instead of a spring-loaded projection off the cover. It is usually better to do thought experiments than to produce something, and then learn about Murphy.

John

PS--I just did a search on "rebreather mouthpiece" and found this:

http://www.rebreatherworld.com/inspiration-evolution-rebreathers/9258-stuck-mouthpiece.html

Note that there was one dive aborted because of mouthpiece problems, as described in this thread.

 

[Luis H]

I liked harassment training, it was a lot of fun.


You can Google and find information about Navy re-breathers. There is a lot of public knowledge. You are not going to get any fabrication details, but you can see pictures of the DSV. Any re-breather diver can tell that they are of very similar design as most of the commercial units.


The thread you posted is the opposite problem of what you are proposing to solve. What you are proposing to solve is a non-issue.