Most Redundant OC SCUBA?

[lowviz]

I totally see your point, I'm not trying to be difficult. My point is that is that I see it as a form of "research and problem solving" limited by materials at hand. This is a very "real-world" scenario. Both his results and his methods are interesting to watch.

 

[John C. Ratliff]

Halocline, you forgot to see the question mark on the op-ed title. The title was a question, not a statement. I put that in purposely to allow discussion of this type of system, and possibly a determination. If you'll read through the whole thread, you'll see that I have conceded that this is not the "most redundant" system available. However, it does stimulate thinking, and that was my goal.

Now, concerning the long hose, I have one, and it does markedly improve performance on the regulator I put it on, which is the original Calypso by U.S. Divers Company (from the early 1960s, with the exhalation diaphragm in the main diaphragm). But it also has a limitation--the original orifice of the tank valve.

It's like a river with a dam, and a reservoir. That reservoir can be opened, and water flows. If it is opened hugely, the water will flow until it matches the creek that is feeding it upstream, and then it will flow no faster. But if there are two creeks upstream feeding that reservoir, then it will flow twice as fast once the reservoir is depleted.

Now, getting back to my long hose, I put it on the Calypso on purpose, so that if I ever dived with guys who were DIR, I would have a regulator that met their specs, but would also cause some conversation. I have a pressure gauge on it, along with a splitter and a safe second, which is a second generation Calypso with the original neck strap. I have an LP inflator hose on it too.

I just recently bought a Dacor Quantum regulator, which I consider the grandchild of the orginal Calypso regulator, as it incorporates the same design features with a better, higher volume exhaust. I had it as the safe second on the A.I.R. I setup pictured here.

Concerning my tests, I have what I have, and it did show a difference. I am not a commercial facility, nor a dive shop. I simply am using what I have available. You can question the test methods, which is fine. But try to show some test results of your own. It appears that you have both the Pilot and the A.I.R. I, so run a few tests with better equipment, preferably with charted IP reductions and correlated to both a 2 L/breath and a 4 L/breath respiratory volume. I am curious about the results.

Thanks for the information on the metal poppet. I did not know such a creature existed. I'll make an inquiry with a LDS I know and see whether one is available.

SeaRat

 

[John C. Ratliff]

Lowvis, thanks for that post.

I took that set of doubles with the A.I.R. I second stage tied into the Scubapro and MR-12 first stages into the pool yesterday (the river is now not dive-able, as the winter rains have come early). I started out with about 600 psig in both cylinders, and was in the water about 15 minutes. I was interested in how it performed with both regulators, and with one regulator shut off (by activating the reserve). With both J-valves in the "On" position, I got significant resistance. With only one on, I could breath fine, but on hard inhalation I could feel a bit of resistance. With both J-valves "pulled" so as to get air out of both cylinders I could breath again without resistance. I breathed the system down to about 200 psig in the cylinders (probably about 50 psig difference between the two). I did not get resistance while breathing during a fairly hard swim.

I brought the system home, and checked again the interstage drop using my ol' intermediate pressure gauge with the cylinders:

At approximately 200 psig cylinder pressure
Interstage Pressure: 130 psig
Hard inhalation pressure, two tanks: 110 psig
Hard inhalation pressure, one tank: 105 psig (one J-valve in up position)

At approximately 150 psig cylinder pressure
Interstage Pressure: 130 psig
Hard inhalation pressure, two tanks: 110 psig
Hard inhalation pressure, one tank: 95 psig (one J-valev in up position)
With both J-valves up: 0 psig (no air can flow past the 300 psi springs in the J-valves)

My conclusion is that while this is not the most redundant open circuit scuba, it has an advantage at low cylinder pressures by increasing the surface area of the supply (two cylinder valves verses one, with twice the surface area of the openings).

SeaRat

 

[dead dog]

Maybe you can point out a couple of "unnecesarry" items

You really want to see what is "unnecessary" ?



What is there 8 or 9 tanks ? That's what I call unnecessary !
Looking at the light off the reef he must only be down about 40 feet.

[/QUOTE]

 

[dead dog]

Front-to-finish, this defines my interest.

I think that you, like most, consider change to be something that must always be better to allow for progress. Change that uncovers hidden weaknesses is also progress.

If we didn't have change we would all be diving with 72 cu. ft. tanks with double hose regulators, solid lead weight belts.
No BC's , no computers, no dry suites, no weight belts (sand) attached to BC's, no high pressure tanks, no Octo's. no pony tanks. etc, etc.

 

[John C. Ratliff]

If we didn't have change we would all be diving with 72 cu. ft. tanks with double hose regulators, solid lead weight belts.
No BC's , no computers, no dry suites, no weight belts (sand) attached to BC's, no high pressure tanks, no Octo's. no pony tanks. etc, etc.

Like this?

SeaRat

 

[AfterDark]

Like this?

SeaRat

Hey wait that looks pretty minimal! That's a new thing ani't it?

---------- Post added October 18th, 2014 at 09:33 AM ----------

You really want to see what is "unnecessary" ?

View attachment 195453

What is there 8 or 9 tanks ? That's what I call unnecessary !
Looking at the light off the reef he must only be down about 40 feet.

[/QUOTE]

In transit hopefully, descent / ascent? Maybe the guy with the camera had no plans to go where the other was going?

 

[John C. Ratliff]

Hey wait that looks pretty minimal! That's a new thing ani't it?

---------- Post added October 18th, 2014 at 09:33 AM ----------

Nope, that was not new. It is a rebuilt U.S. Divers Company DX Overpressure Breathing single stage regulator, the first in the ling of single stage regs that led to the Mistral. It has longer hoses, and uses the hose-within-a-hose concept for the venturi, which terminates in the metal mouthpiece. This regulator originated in the early 1950s. I have it on a set of twin 45s, usind a Sherwood manifold that has two posts. I have a MR-12, I think, as my safe second (you can just see the hose on the right side of the manifold (left side of the photo). I still have this regulator and occasionally dive it, but this photo is from around 2005.

SeaRat

 

[AfterDark]

Nope, that was not new. It is a rebuilt U.S. Divers Company DX Overpressure Breathing single stage regulator, the first in the ling of single stage regs that led to the Mistral. It has longer hoses, and uses the hose-within-a-hose concept for the venturi, which terminates in the metal mouthpiece. This regulator originated in the early 1950s. I have it on a set of twin 45s, usind a Sherwood manifold that has two posts. I have a MR-12, I think, as my safe second (you can just see the hose on the right side of the manifold (left side of the photo). I still have this regulator and occasionally dive it, but this photo is from around 2005.

SeaRat

No John not the gear the minimal concept. It's not new just something old that is new again. It was an attempt at sarcasm on my part.