Info New ( 2019 ) doubelhose design

[CG43]

This design was first published in the German diving magazine
"DIVING HISTORY ISSN 2510-439X 13-06/2020 " .
https://seveke.de/tauchen/altes/0artikel/th13-falteschlauchmundregler-lange.pdf
After that in Vintage scuba.proboard forum : Titel "The doubelhose mouthpiece regulator Jul 5. 2023 ".
The doubelhose mouthpiece regulator | Vintage Scuba Diving Community Forum

The most important design goal was to construct a doubelhose reg. that regulates to the water pressure at the mouthpiece same as a singelhose reg. does .
First I will only post the functional diagram and pictures, no explanations because I suspect that some colleagues who have nothing better to do on a winter evening, have fun finding out for themselves how it works.
Of course, there are advantages and disadvantages to this design and it is possible to find out only from the functional diagram , but that isn't easy .
For those who already know the design, I ask you to wait a little so that everyone can think for themselves first.
I will answer every question .

 

[Nemrod]

The biggest advantage, despite my waning infatuation, is the exhaust being behind not obscuring vision, pounding ears and scaring off shy creatures. This does not accomplish that.

The intake hose number 9 really should have a cage valve to prevent water from back flowing into the intake hose when the mouthpiece is removed.

Yeah, interesting and clever, but no cigar . On the rare occasion that I would currently use any DH regulator, think Blue Heron bridge or a swimming pool, the good old RAM and Kraken have a powerful Venturi to overcome the less than ambient pressure at the mouthpiece.

 

[Mobulai]

Umm, very interesting!
Do you have a 1st stage diagram; or whatever is attached onthe tank

 

[CG43]

Hello Nemrod

In warm water I use single hose regs. und in cold water doubel hose regs. because of the warmer and not so dry air .
The thread :
Thermal Aspects of OC Regulators : The Air we breath
and:
Thermal Aspects of Rebreather-Design

The intake hose number 9 really should have a cage valve to prevent water from back flowing into the intake hose when the mouthpiece is removed.

It's no problem to do that, but I won't do it for myself because it gives me the opportunity to run some water into the inhalation tube. This makes the air a little more humid, more pleasant and less dehydrationing. In addition, you can save some evaporation energy yourself. This air is almost as good as rebreather gas.
Diving with rebreathers was also the trigger for me to use doubelhose regs. again .
This applies to all doubelhose regs. , I will go into specific characteristics of the design later.

 

[CG43]

Do you have a 1st stage diagram; or whatever is attached onthe tank

Sorry no .
It is a Dräger fire fighter compensated first stage , build like an membrane stage ,
but with a piston instead the membrane . The IP is 7 bar because the second stage is UPstream.
An OPV is build in . The second stage has an ordinary tilt valve .

 

[lexvil]

Rampant drug use comes to mind, guessing on some mushrooms it could be amazing…

 

[Nemrod]

I like it, I had a similar idea a long time back but this is better. But, the sense hose does not need to be a full size corrugated hose and could be installed coaxially inside the the intake corrugated hose and the other used to exhaust the spent gas at the rear like a proper double hose!

The other part of the idea is to then use the sense line equipped at the mouthpiece diaphragm with a tilt valve to create the vacuum needed to servo the main airflow, a servo assisted first stage, tilt valve in the mouthpiece with the ambient chamber much like the OPs design. No large diaphragm now needed at the first stage.

 

[CG43]

I like your post very much .
We both tried the same thing, and we are not the only ones.
Especially in the early days, the circumvention of the Cousteau/Gagnan patent was a reason.

In " CG45 " there are some very interresting designs :
Heinke twin-horns : weight compensated exhaust valves
Healthways scuba : pneumatic freeflow protection
Scott Hydro Pack : pneumatic freeflow protection and power clearing the FFM
Pirelly Explorer : diaphragm-controlled additional exhaust valve
Demone : water vented exhaust hoses .
(not in CG45) Dräger Pa 38 : Water/ Air Doubel Compensated Exhaust

I like it, I had a similar idea a long time back but this is better. But, the sense hose does not need to be a full size corrugated hose and could be installed coaxially inside the the intake corrugated hose and the other used to exhaust the spent gas at the rear like a proper double hose!

In my design, I need the exhaust valve in the middle of the storage diaphragm to generate the sense pressure. An extension to the rear would only work as with the "Demone", but which means that with each exhalation the water from the hose must be blown out again and that is BS .

The other part of the idea is to then use the sense line equipped at the mouthpiece diaphragm with a tilt valve to create the vacuum needed to servo the main airflow, a servo assisted first stage, tilt valve in the mouthpiece with the ambient chamber much like the OPs design. No large diaphragm now needed at the first stage.

When the pilot valve on the mouthpiece is connected to the main valve on the back with a hose, the hose volume slows down the response of the valve. A slowly closing 2nd stage valve is the last thing you want in your mouth .
However, in combination with a very powerful pressure relief system that also reduces the likelihood of getting water shot in the throat, such as a full face mask, this can be a very good option. And now you can lead the exhale backwards if you use a pneumatic anti freeflow exhaust valve?

 

[CG43]

The design .
A doubelhose reg. must lie close to the shoulder blades in order to breathe easy in the swimming position. In most modern configurations, this is not feasible. The photo shows my doubelhose backplate and my replica reg. close to the first Cousteau/Gagnan CG43.
First stage separated to the second stage , two upstream valves and no valves in the mouthpiece .
This scuba has been used for fair comparison with the doubelhose mouthpiece reg. , because the second stage sits optimally on the back and the 2nd stage is the same .

This stage , of course has openings to the water. By closing the openings with the PVC plate (bottom right in the picture) and removing the mushroom valve, the stage can be converted for doubelhose mouthpiece reg. use .

Since the 2nd stage is isolated from the water pressure in my design, it can be mounted at any location. The tester Lothar Seveke, for example, used cable ties to fasten the 2. stage far away from the back.
The position of the reservoir can also be chosen, which I also liked to use. That my choice was similar to Dräger Shark, SP Pilot, SP D400, Atomic TFK can only be a coincidence.

Now the most interesting and problematic part: the reservoir No. 2

On the water side of the reservoir diaphragm, different water pressures act, which in the sum in No. 2, No. 4 and No. 6 generate a sense air pressure that corresponds exactly to the water pressure in the middle of the membrane. Unfortunately, this only applies as long as the membrane can move freely.
For this reason, the diaphragm reservoir No. 1 must be able to displace as much air as the inhalation membrane No. 5 needs to move. Unfortunately, the reservoir is getting big.

Safety disadvantages :

1.) If one way valve No. 8 is leaking badly :

In order to avoid suction via hose No. 4 on the back of the inhale diaphragm No. 5 during inhalation, a one way valve No. 8 must be installed in the reservoir inlet.
If one way valve No. 8 is leaking badly, inhalation is no longer possible !!!

2.) Quick raising pressure :
If you dive down quickly without exhaling, part or all of the variable volume of the reservoir is used up to compress the air in reservoir No. 2 , hose No. 4 and chamber No. 6 . Before the next inhalation, it is then necessary to exhale a little. This effect is most pronounced at shallow depths, where the volume decreases the fastest . Although this problem is easy to avoid, it remains a safety disadvantage.
The design uses the exhaled air to generate the sence pressure without much effort and without air consumption. As is almost always the case in technology, there is then unfortunately also a price to pay.