Duckbill mods.

[treasureman]

with the talk about disintegrating duckbills, I got to thinking (yes Komrade thinking will be reported) that do we need the flapper. I picvked up a one inch dia purge valve which includes the cage for the silicone valve.

I have married this to the duckbill after i cut off (gasp..blashpemer) the flaper part of the duckbill.

It exhales easier from what I can tell. Problem is the one inch purge valve and associated cage is too large. I need something smaller to experiment with. i have canvassed the LDS to see if I could scavenge from their used piles to no avail.

if we can find the right size, and it fits inside the can and does not interfere with the diaphragm at all, then we eliminate using glue on the flapper parts to stick it to thew can, and we could then just produce a silicone sleeve which would require less mold, and last longer. The valves could be found and bought for spit. Key as I see it is the right diameter purge, then test it to see how it functions.


I have some mould making material and may try to produce a plastic horizontal valve which would fit the width of the duckbill siderways so it would lie flat in the can. But that is a few weeks away before i get to it.

Any suggestions or if anyone has smaller cages with purge valves, let me know if you want to sacrifice them to the experimental gods of vintage diving.

[oldmossback]

Treasureman

I've toyed with modifying or changing the duckbil myself.......one concept I thought of was to use a piece of rubber tubing (bicycle inner tube) with one end sealed off, the other runing thru the horn and flipped over as is normal with the duckbill.......

on the end that is sealed, cut a circle big enough for the purge valve and cage to fit in.....glue this in place.....you have a flexible tube that rides with the diaphragm and a mushroom valve.......you might have to cut the valve cage down in thickness to allow room in the back side of the can....

Oldmossback

[treasureman]

god ideas. I will tinker with this and see what happens

[diverdown1955]

I have been playing with this same idea, the mushroom valve exhales much easier than the duckbill. I inserted the cage into the exhaust hose at the front end of the horn. Of course the hose corrigations allowed some seepage. A plastic cage with a half circle to project outward into the hose corrigation would help hold it in place and tie wraps in front and to the rear of the positioning corrigation would seal it to the plastic cage. Not a long term idea as I would imagine the tie wraps will cut the hose at some point. Now I am planning to cut a 1" bike tire tube glue the cage to the rubber tube. A portion of the tube will go over the horn the cage and MRV goes into the hose then the hose slides over the bike tube (much like when the duckbill is installed).
In a perfect world that should work. Before I get too carried away tearing up this cage and MRV I would like to find a supply of these items. I got this one from my LDS and he had no idea what it came out of. The ideal solution would be an exhaust hose with an additional 1/2- 3/4" of smooth tubing to allow insertion of the cage, one hose clamp on the cage and one clamp to attatch the hose to the exhaust horn. I have not tried this on Dan's new accordian hoses yet , they may have more internal diameter than the stock RAM hoses. Duckbill be gone !

diverdown1955

[JES]

Very interesting ideas.

Like they say, "Necessity is the mother of Invention"

[luis]

The exhaust mushroom valve (or duckbill) should be right in front of the diaphragm or you are going to get a free flow when you roll to your right. In that position the exhaust will be higher than the diaphragm (if the exhaust is short). Some will depend on how sensitive is your regulator. I am having a little bit of this problem because the duckbill is a little short with my extremely good breathing experimental Phoenix RAM. This regulator is so sensitive that I don’t consider this a bad problem. The exhaust only has to be a bit higher that the intake diaphragm and it bubbles a little bit.

I have been thinking of designing and making a sheet metal (stainless, aluminum, or copper: for a prototype) cage to mount a mushroom valve in front of the diaphragm and facing the diaphragm. This is similar as the Nemrod and other regulators. It is nothing new. The challenge is how to attach it without cosmetically affecting a good exhaust can and not restricting the exhaust flow. I have some ideas; I just don’t have the time or the fabrication resources…again.

[treasureman]

I have just about finished a simple effort at making the duckbill a bit easier. I have cut down the cage significantly on the purge valve, so it is less than an eight inch thick, with a wide flange which can be glued to a duckbill sop it will be on the side rather than the end. I need to seal up the flapper edges So i can use the width of the flapper. If I understand correctly from Luis post, the shorter the duckbill, the greater the free flow when youy roll to the right?

If this works, the duckbill need only be made longer but without the flapper part.

Do I have any happy komrades that want to test this Rube Goldberg contraption when it is done??

[luis]

I have just about finished a simple effort at making the duckbill a bit easier. I have cut down the cage significantly on the purge valve, so it is less than an eight inch thick, with a wide flange which can be glued to a duckbill sop it will be on the side rather than the end. I need to seal up the flapper edges So i can use the width of the flapper. If I understand correctly from Luis post, the shorter the duckbill, the greater the free flow when youy roll to the right?

If this works, the duckbill need only be made longer but without the flapper part.

Do I have any happy komrades that want to test this Rube Goldberg contraption when it is done??

Can you post some pictures?

Yes, the exhaust needs to be as close to the center as possible if the regulator has been tuned to be very sensitive. Today I was using my experimental Phoenix RAM again and it had a small free flow every time I got vertical. The exhaust is in the top left of the can. I need to detune that regulator justa tad.

[YankDownUnder]

Heinke began making double hose regulators with a number of unique variations in their design. They solved the duck bill exhaust valve problem by placing a cart wheel valve in the hose, just outside the exhaust horn.

I have a Heinke MKIII in new condition. It is identical to the first regulator I bought in 1961, and that's what has been done. Just how they got that cart wheel mushroom valve in the hose I have no idea. It sits two corrugations back from the horn. The hose may have been warmed up and lubricated. The cart wheel is the same as those used in the mouth piece assembly.

If you want to eliminate the duck bill exhaust, this may be the way. If Stuart starts making his silicone hoses, it should not be too hard to insert a cart wheel, but I would not try it on valuable original hoses which may have hardened over the years and could split.

[JES]

YankDownUnder,

Thank you for the information on the Heinke MKIII. I wonder how this setup works since a duckbill needs to be as close to the center of the diaphragm as possible if the regulator has been tuned to be very sensitive.

Do you get any exhaust free flow leakage with your regulator?

[treasureman]

The cage and valve I just cut dopwn was 1 inch dia. it may have fit nicely in the hose. I know the dive store has one more l;eft. I will pick it up and try it out in the hose

[duckbill]

My breathing style seems to favor a mushroom valve over a duckbill, for some reason. I inhale deeply and exhale very slowly (if not working hard) for maximum oxygen absorption and dive time. When doing this, I almost always get water seeping through the duckbill while the openings are open during exhalation. It can be really annoying. I assume it is because there is very little pressure or velocity at work keeping water from entering. I tried my friend's Dacor R4 and it stayed nice and dry. If anyone could make a non-permanent drop-in unit with a mushroom valve to replace the duckbill, that would be GREAT.

[diverdown1955]

I think Heinke got it right. The caveat being , you accept the two hose and its characteristics for what it is, not a single hose. In MHO the MRV in the exh hose just ahead of the horn would suit me fine. I dove many years w/o a duckbill depending on the MRV in the mouthpiece to keep the water out. My regs are not supertuned for easy breathing, I have a scubapro MK VII for that qwirk in my nature.

diverdown1955

[treasureman]

The idea of a flat square or rectangular tube which fits on the inside of the reg and the inside of the horn (rectangular portion) I think will have the most promise. I bought some plastic sheet, anmd will glue up a box that will take it to the middle of the box. A short piece of duckbill will then be used to attach the plastic tube to and the end of the duckbill will be turned over the horn as usual. A mushroom valve will be cemented over the plastic tube, and it should be just the ticket.

If I get a chance this week, I will cut the pieces and fuse the parts together to see if they will fit. See what it looks like. If I can figure out how to post pix I will do so. All my previous poix were posted by my son who of course is away on his girlfriend for the summer

[treasureman]

Ok it took a few hours of scrounging, but I found a perfect COTS rectangular box to use inside the exhaust box. What this item is used to contain blades for the OLFA box cutters. It is a tight snap in fit right into the inner exaust horn.

here is what needs to be done to make it work.

I have some card stock (plastic).

The OLFA box is just a milimeter too high IMHO to work properly without crowding the diaprhagm. I will measure out, and reduce the height by this one Mil on its thickness.

The width is just a optuch too narrow to properly accomodate a mushroom cage with valve also by one mil or so.

When I make the box from the plastic card, I will make it diamond hape towards the end, where the duckbill was wider. This should then allow accomodation of various size mushroom valves.

Further I was in the plumbing store and found some commercial flushing devices for mens urinals. The level handle that is spring loaded.

In any event, they have a 2 inch diam mushroom valve in theior repair kit. It would not take much effort to make a wider diamond area to accomondate the large wagon wheel and valve, and it should not interfere with the diaphragm operation. I am going to try and put a rough out version together. There may still have to be a rubber connection to tie the end of the plastic tube to the horn, but at that point it eliminbates a whole bunch of extra mould, and perhaps as others have suggested, even a bit of 1 inch bike tube could suffice.