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Discussion of diving methods and equipment available prior to the development of BCDs beyond the horse collar. This forum is dedicated to the pre-1970 diving.
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SurfLung
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Re: "Build Your Own Diving Lung", Revisited in 2018

Tue Aug 14, 2018 11:29 am

The answer might be in the CG-45 web page on Sea Horse diving equipment. Sea Horse actually manufactured diving equipment based on the modified diluter. If you scroll down to the catalog, the bottom paragraph of the description of the Demand Regulator says,
"Discharge is directly to the water with two advantages:
1. Inhaled and exhaled air are never mixed.
2. Any accumulated water can be easily expelled and cleared through the non-return mouthpiece."
See http://www.cg-45.com/regulators/Sea_Horse_Pitsburgh/

There's also a page on Home Made regulators that might give some ideas.
See http://www.cg-45.com/regulators/Homemade/
(Scroll Down to the Bottom When You Get There.)
index[4].jpg
I don't know if this is any help. But it is certainly interesting! :)
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SurfLung
The Freedom and Simplicity of Vintage Equipment and
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antique diver
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Re: "Build Your Own Diving Lung", Revisited in 2018

Tue Aug 14, 2018 12:00 pm

SurfLung wrote:
Tue Aug 14, 2018 11:29 am
The answer might be in the CG-45 web page on Sea Horse diving equipment. Sea Horse actually manufactured diving equipment based on the modified diluter. If you scroll down to the catalog, the bottom paragraph of the description of the Demand Regulator says,
"Discharge is directly to the water with two advantages:
1. Inhaled and exhaled air are never mixed.
2. Any accumulated water can be easily expelled and cleared through the non-return mouthpiece."
See http://www.cg-45.com/regulators/Sea_Horse_Pitsburgh/

There's also a page on Home Made gear that might give some ideas.
See http://www.cg-45.com/regulators/Homemade/
index[4].jpg
I don't know if this is any help. But it is certainly interesting! :)
EBEN, this is definitely helpful, and reinforces my thoughts on the external exhalation port. This is good information. That last photo is very similar to what I have been toying with. I'm currently trying to use that cockpit air mixing input just as a mounting point for a copper fitting going to an external duckbill-like valve, but was looking at putting mine on the side since that side of the reg body will be right up against my back. The location shown at the center of the diaphragm is probably better. It will be close to my back, but may work out if I just make a little extra room between the reg and my back.

It's never going to be a great performing reg no matter what I do, short of a front-chest mount. I tried that in the pool and it made a very impressive improvement in performance! Only downside to that is extra stuff to strap on when donning the equipment, and I wanted to keep it as simple to use as possible.

Plan now is first to continue development of the back mounted reg, and get it workable since that was my first goal. I also plan to experiment further with a simple chest mount as I think that has some possibilities. If it will quickly convert from one to the other with no changes to the reg I would be pleased.

THANKS for your input! :D
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Vancetp
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Re: "Build Your Own Diving Lung", Revisited in 2018

Tue Aug 14, 2018 12:33 pm

The picture Eben posted with the duckbill attached to the outside of the regulator bottom can shows the basic idea I was thinking of. The unprotected duckbill seems like a bad idea since it is potentially able to be pressed against the diver's back and closed/restricted. Something like this duckbill cover on my Russian AVM-1M could be done with a DB or a mushroom valve:
ImageAVM-1M6 by Vancetp, on Flickr

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ScubaLawyer
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Re: "Build Your Own Diving Lung", Revisited in 2018

Tue Aug 14, 2018 12:40 pm

Phillip,

Этот дизайн действительно интересный!

Mark
"The diver who collects specimens of underwater life has fun and becomes a keen underwater observer. .. seek slow-moving or attached organisms such as corals, starfish, or shelled creatures." (Golden Guide to Scuba Diving, 1968) :D

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Vancetp
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Re: "Build Your Own Diving Lung", Revisited in 2018

Tue Aug 14, 2018 1:24 pm

If you think this one is interesting, check these out ! There are several home made regs here. I especially like the one made out of a Bosch car klaxon!

https://www.vsc-ds.cz/sbirka/dvouhadico ... regulatory

These have the exhaust exiting without entering the can, but from the base of the horn through drillings. That isn't perfectly balanced, but apparently worked for their owner/builders for years of service!

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SurfLung
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Re: "Build Your Own Diving Lung", Revisited in 2018

Tue Aug 14, 2018 3:29 pm

I vote for the external duckbill... Just because it's authentic to the way these were made. I'll give a word of caution about the new silicone duck bills. They are so pliable that they can get sucked back into the hose during free flow or purging and make it impossible to exhale. I prevent this by gluing the back side of the duck bill to the regulator can with a drop of silicon glue. :)
SurfLung
The Freedom and Simplicity of Vintage Equipment and
Vintage Diving Technique are Why I Got Back Into Diving.

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antique diver
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Re: "Build Your Own Diving Lung", Revisited in 2018

Tue Aug 14, 2018 7:03 pm

Thank you Eben, Mark and Phillip. There was a wealth of ideas in those old pictures. The chest mount shown in the Newnes Practical Mechanics goes along almost exactly as I had been thinking for ease of breathing after briefly holding my whole rig, tank and all against my chest. I had been thinking it might require a separate harness for the reg body, but looks like they may have just attached to the chest cross strap. I think I will be trying this after I finish up the conventional mount first.
chest mount.jpg
Looks like they have used a first stage regulator on the tank with a hose coming into the external demand stage port.
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Vancetp
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Re: "Build Your Own Diving Lung", Revisited in 2018

Wed Aug 15, 2018 2:22 am

Apropos of the drawing, I have a Russian AVM-3 which is a second stage double hose regulator. The first stage was remote and air was piped into the second at the fitting on the bottom. It can also be fed from the capped fitting going off up and at an angle. I've been toying with the idea of a chest mount harness and connecting the can to the first stage with a hose much like your picture.

ImageIMG_3069 by Vancetp, on Flickr

The stack of fittings are adapters running from M16x1.5 to 1/4"npt to the BC vest QR.

ImageIMG_3067 by Vancetp, on Flickr

It actually breathes pretty well, even though it looks almost as scary as your diluter setup! I don't mean to hijack your thread, but thought this was relevant enough. I'd like to go to school on you concerning any harness you make up.

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antique diver
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Re: "Build Your Own Diving Lung", Revisited in 2018

Fri Aug 17, 2018 11:14 pm

I could use some suggestions on exhaling valve.

I was planning to use something like the Duckbill for initial use, but thinking the Silicone duckbill is a little too soft and flexible. I have no trouble with them in normal use in the horn of double hose regs, but for exposed use I'm not sold on them. I was going to try a Broxton-type as it's a little stiffer and holds position better, but upon closer inspection both my extra ones have some weak points that rule out using them.

Anyone have any luck making a similar flutter valve arrangement? (I used a cut off balloon on a pipe tee on my Hookah rig in 50's and it worked surprisingly well, so maybe I'll look for a heavy duty balloon. ???

Maybe I'll just go with making a frame for a mushroom valve that can fit safely up into the copper fitting outlet that could be mounted on the outside of the Bendix housing. I'm sure they must have been used in the Oxygen masks and similar applications so I could still be historically accurate.

Suggestions and ideas welcomed!
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Re: "Build Your Own Diving Lung", Revisited in 2018

Sat Aug 18, 2018 12:32 am

I haven't had a chance to make any real progress this week, so I'll post some photos of the first stage workings. There is a surprising mechanism within the first stage that operates the first stage poppet, unlike anything I have seen before in a regulator. I'll show that later, but first things first.

Here's a look at the first segment of the first stage, with some explanations below the photo.
24.1st stg orifice + bypass.JPG
The first stage air inlet orifice is found in the small aluminum body with the manual bypass mechanism. The HP poppet is the light colored object that looks a lot like a miniature revolver cylinder. It has six holes that are are just air passages. The red valve knob allows user to bypass air around the seat mechanism in the event of some malfunction there. It allows fine tuning of a constant flow of air (from very slight to fairly heavy flow) which might be of some use to a diver if exertion requires greater volume than the demand functions can provide. The pick is pointed to one of the free flow orifices bypassing the brass volcano orifice and poppet, also bypassing the 2nd stage demand valve, and leading directly into the main regulator body. Four of the other holes are for the machine screws that hold this mechanism in place on the main body. Sort of comforting to know you have a straightforward source of air in case the first or second stage goes kaput, so I'm leaving it intact and functional.
23.first stage nozzle + seat.JPG

Here the poppet is shown in position. The small brass screw and nut is the contact point for the activating mechanism of the 1st stage. It is adjustable, but otherwise just performs the same function as the pin in a diaphragm type first stage. But, this sophisticated regulator does not have a diaphragm, or type of spring that we are familiar with. The unique pressure sensing mechanism pushes a lever that pushes against the poppet screw, thereby pushing the seat against the brass volcano orifice, and shutting of the HP air when there is no demand for air. When user inhales the second stage opens, intermediate pressure drops allowing the poppet seat to open and provide air flow. So it acts like any other first stage, but it's not.
26.bellows 1st.JPG
In this photo the rest of the first stage is shown with its relief valve/cover removed, revealing a sealed air filled brass bellows. When the surrounding chamber fills to proper pressure the bellows is compressed in length, pulling down on the lever attached at its top end. The other end of that lever pushes the poppet into the closed position until the pressure drops upon the next inhalation. The small hole in the side of that first stage chamber leads to the second stage. When the second stage lever is pulled down upon inhalation the air flows to left, into white tube that I added. That connects to the brass tube that is aimed directly at the inhalation hose opening.

I hope to have some time this weekend to reconfigure the hoses in a manner that does not allow exhaled air to enter the regulator body.
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Re: "Build Your Own Diving Lung", Revisited in 2018

Sat Aug 18, 2018 2:07 pm

Bellows photos to help clarify how they work in the Bendix:
29.Bellows retracted.JPG


The item in above photo is not the first stage bellows (that I did not want to remove), but is built basically the same. This is a smaller one from the automatic air to Oxygen mixing valve. It senses atmospheric pressure and operates a delicate valve that mixes an appropriate ratio of Air to Oxygen for any given altitude. Had this not been removed for diving it would mix incoming air and water in a very inappropriate ratio!

Next photo is the same bellows extended in a little jig for illustration. This extended position is similar to how it would look at high altitude as the internal gas expanded as compared to atmospheric pressure, but I have exaggerated the expansion amount for demonstration of the bellows operation.
30.Bellows extended.JPG
The actual first stage Bellows (or maybe they call it a diaphragm) is larger but looks almost identical. It too is sealed, but is is extended in its relaxed state, and responds to external pressure of incoming breathing gas pressure by compressing (retracting). When the set adjustment for Intermediate Pressure is reached the lever assembly pushes the HP seat/poppet against the incoming air orifice.
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Vancetp
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Re: "Build Your Own Diving Lung", Revisited in 2018

Sat Aug 18, 2018 3:15 pm

What is the duty cycle for the brass bellows? Metal fatigue has to be a factor in how many times it can flex.

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antique diver
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Re: "Build Your Own Diving Lung", Revisited in 2018

Sat Aug 18, 2018 3:55 pm

Vancetp wrote:
Sat Aug 18, 2018 3:15 pm
What is the duty cycle for the brass bellows? Metal fatigue has to be a factor in how many times it can flex.
I have no idea. There was likely some specification from Bendix about time intervals for servicing units and replacing certain parts.

For diving use I guess it will be when I get water instead of air. :shock:

BTW, since my last post I have seen the brass bellows in the air/O2 dilution works referred to as a "Barometric Capsule".
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Re: "Build Your Own Diving Lung", Revisited in 2018

Sun Aug 19, 2018 11:59 pm

Still looking at options on the exhaling side configuration, and something similar to this will be tested in the water soon. The end of the Tee going into the body is sealed off, and just used to mount the exhaling system firmly to the body. No exhaled air will enter the reg body. The angle of the outlet branch is adjustable by turning the Tee, and secured by a setscrew. The duckbill is temporarily attached to a 45 degree fitting in that branch to keep it close to the body. All angles are temporary at this point, and not yet considered final until the performance is evaluated. Probably will leak air out if I turn my position down on the right side underwater, but I don't know without testing if that will be much of an issue.

I don't particularly like the hose horns in the somewhat asymmetrical configuration, but I doubt that it will be an issue in actual use. Anyway, it's just for a test to see what other changes might be necessary. I also have a lower profile tank valve to try out. Just a single tank for now, but may end up using small doubles. I want to try to stick with some type of duckbill for the exhaling valve for now, but may use some type of protective shield around it later.
31.Exhalation config.JPG
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antique diver
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Re: "Build Your Own Diving Lung", Revisited in 2018

Thu Aug 23, 2018 5:38 pm

Wife to Bill:
When are we going to start remodeling the other guest bathroom? Why is that Aviator thingy taking so long?

Bill to Francie:
Well, I've got work projects too, and need to balance that with fun stuff, like creating a really unique and interesting diving regulator just like guys were using back in the late 40's and early 50's. That's important to me.

Francie:
Just guys, huh? I guess the girls had better sense.

Bill:
This is an extraordinary undertaking, and if not done right it could be really dangerous! I've heard people died using these things.

Francie:
Oh... how much life insurance do you have? Show me where to find the papers.

Bill:
I won't go deeper than I'm willing to come up without air. Probably carry a pony bottle too until I make sure it doesn't blow up underwater.

Francie:
Do you know if you had spent all that time taking on a little more part time work you could have paid for two of those beautiful KRAKEN regulators by now!

Bill:
(Speechless).... :shock: (realizes she is right again!)
The older I get the better I was.

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