Modern Doublehose???

[John C. Ratliff]

The diagram that Nemrod posted comes from Bill Barada' book, Let's Go Diving, Illustrated Diving Manual, published by U.S. Divers Company in November 1965 (4th printing).

Pescador775, thanks for the mention of the Demone Mark I and Demone Mark II regulators. They were a single hose concept, with a second corrigated hose to take the diver's bubbles away that was wrapped around the Lp hose. The Demone Mark II had two hoses, and so operated better in all positions, as one hose was always higher than the second stage at the diver's mouth. These hoses were flooded, so the actual non-return valve was at the second stage near the mouthpiece, and the flooded corrugated hoses simple moved the exhaled water away from the diver's head when the diver exhaled. The interesting thing is that this was a pilot-operated tilt valve (actually two of them, one coming from each side for the Demone Mark II) incorporated into a single second stage. I have never used one, but my LDS has one hanging up in the shop. This gives me some new ideas for my own new regulator configurations. Thanks.

SeaRat

 

[Spimon]

Only other 'problem' with the original doublehoses I can think of is the size and shape. I remember reading somewhere on here there was mention of problems fitting a doublehose to a modern BC without hitting the top of the wing (I think). I dont know the exact details, but would be nice to have one that would fit essentially all varieties of BC without any problems.

 

[captain]

Just as many modern fighter aircraft are inherently unstable and could not be flown without the fly by wire computers that transform what the pilot is asking the aircraft to do into control surface motions that are too complicated for the pilot to do alone, the double hose that will breathe the same in all positions might need the help of electronic control for air delivery.

 

[Spimon]

Ah Captain's got it! If anyone can find a way to do it (either electronically, mechanically or any other way) they'll probably be onto a very successful product.

Maybe instead of adding the desireable modern features to an old reg, add the desireable old features to a modern reg.

 

[DA Aquamaster]

Making a better double hose is an admirable ambition, but just because the vintage double hose technology was old, did not mean it was not well advanced.

For example, if I made a piston engined fighter aircraft today, I'd have to work hard to improve up on the pinnacle piston engine designs of 50 years ago - the P-51, F4U-4, FG-2, F8F, Seafury, etc.

A "new" one could take advantage of composite air frame materials to save some weight and allow for some smoother lines, but at the expense of easy repairability. The end result however would end up having an awful lot in common with it's 60 year old ancestors. Even if I added a turbine engine overall performance would not be significantly better due to the limits of propellers and maximum airspeeds -ie: physics.

In terms of a making a new double hose, most of what you are asking for on your list is already available in the vintage market on a reg like the PRAM - except for:

1. Price
However $350 does not buy much in a single hose reg, so that amount is arbitrarily low. If you up it to the level of any other upper end reg, you can already get one at that price. I rebuilt a DA, had it rechromed, retrofitted it with all new soft parts and added a Pheonix nozzle and custom labels for about $650 - no more than I would have paid for a MK 25 S600.

2. Easy breathing in any position.
As captain suggested, you could use electronics to resolve that. I suspect a depth sensor in the mouthpiece and one in the can could interface with a small control unit that would increase or decrease pressure on the LP seat, lever or diaphragm to allow a lower or higher inhalation effort based on relative positions of the sensors. Of course, you'd have a $1000 reg by the time you got done.

3. Accomodate a modern mouthpiece. That would be fairly easy to do even for existing double hose regs. You just need to mould a piece of plastic that will accommodate USD wagon wheels and hoses with a suitable attachment for a standard mouthpiece. The trick is to keep it small in over all size weight and volume. If you go bigger it should be to incorporate a shut off valve to prevent freeflows on the surface.

With that for competition, it would be extra daunting for a company to try to field an all new double hose reg.

 

[Nemrod]

FADBC, Full Authority Digital Breathing Control. Electronic regulators will not have diaphrams, they will not have levers and pistons and diaprhams. There will be several chips, computers, that analyse the human needs, have a breathing curve programmed in, use piezo sensors to measure pressure and servo valves to open and close to release air. You guys are not ready for that. They will come when we see parallel dvelopemnt with open circuit equivilent to closed circuit. An electronic regulator would be very small and light, it would look nothing like todays hub cab in the face rigs much less our venerable old double hose rigs. In a "packaged set of double or tripled tanks, it could mix nitrox for example on the fly to suit depth and mix O2 when ascent begins to facilitate off gasing. N

 

[DA Aquamaster]

I still like the Keep It Simple Stupid principle and it would be great to avoid electronics as much as possible.

The mouthpiece itself "senses" vacuum pressure. So a higher inhalation effort could be sensed with a tube running to the mouthpiece. You'd just need a vacuum actuated servo valve of some sort in between the case and diaphragm to assist or retard movement of the diaphragm. It would not be overly complex and the whole system could run off IP air.

 

[Nemrod]

I have a sketch somewhere of a pneumatic servo design that utilizes a small diaphram about the size of a quarter in the mouthpiece which displaces a tilt valve. The tilt valve controls a balance chamber which would of course include the sense tube that runs through the breathing hose back to the second stage. The reduced pressure in the balance chamber initiated by the tilt valve in the mouthpiece displaces the second stage main flow valve. It is essentially a hybrid of a single and double hose. Why do this? OK, it would still retain the double hose look, it would still have the rear exhaust for bubble free vision, it would still have the lightweight compact mouthpiece that only a double hose has, it would still have the high flow rate that the double hose has along with the mostly environmentaly sealed second stage of the double hose. Additional benifits of the design, it could have a purge valve, it would not suffer from the positional disadvantage that the standard double hose suffers when in the primary swimming positon, that being the diaphram above the lungs. The second stage contained within the cans is still environmentally sealed and there would be no diaprham, simply a sealed metal case, the only diaphram would be the quarter sized one in the mouthpiece. If this sounds like a double hose Tekna T2100, yeah, it is. BTW, the exhaust hose would probably have to be a flooded type to prevent free flow. N

 

[Luis H]

I have a sketch somewhere of a pneumatic servo design that utilizes a small diaphram about the size of a quarter in the mouthpiece which displaces a tilt valve. The tilt valve controls a balance chamber which would of course include the sense tube that runs through the breathing hose back to the second stage. The reduced pressure in the balance chamber initiated by the tilt valve in the mouthpiece displaces the second stage main flow valve. It is essentially a hybrid of a single and double hose. Why do this? OK, it would still retain the double hose look, it would still have the rear exhaust for bubble free vision, it would still have the lightweight compact mouthpiece that only a double hose has, it would still have the high flow rate that the double hose has along with the mostly environmentaly sealed second stage of the double hose. Additional benifits of the design, it could have a purge valve, it would not suffer from the positional disadvantage that the standard double hose suffers when in the primary swimming positon, that being the diaphram above the lungs. The second stage contained within the cans is still environmentally sealed and there would be no diaprham, simply a sealed metal case, the only diaphram would be the quarter sized one in the mouthpiece. If this sounds like a double hose Tekna T2100, yeah, it is. BTW, the exhaust hose would probably have to be a flooded type to prevent free flow. N

Yep, if the sensor is in the mouthpiece you would need flooded exhaust hose.

Sounds like a modern version of the Demone.


Different approach is to add resistance to the exhaust similar to the Pirelli regulator, but I don't believe it worked that well. I think the exhaust hose in the Pirelli had to free float in order to always be above the mouthpiece by a somewhat fixed distance.

 

[pescador775]

I considered most of the above. Flooded hose aside, a spring loaded exhaust valve would work with the hybrid, tilt valve but only in one position, horizontal. So, the Demone solution is pretty much out. Poseidon has some interesting servo designs and something like that might be possible under DA's theory. I even considered a device to alternately impose a small force on the outside (water side) of the diaphragm. IOW, modify the front box half; install a spring/dowel rod which presses on the diaphragm and is operated by gravity. Branching out from the spring/rod would be two levers, like arms or wings. Gravity would pull the weighted arms down and push up on the rod and against the diaphragm. Oh, well......