1st Stage Diaphragm: Replace or Re-Use?

[halocline]

Apeks Zeagle (it actually came in an Apeks box with Zeagle stickers on it).

They are a lot more alike that either of them would like to admit.
Same goes for most other diapharm regs. Start measuring them and you will find the main diaphram on pretty much all of them are within a few thousands of each other or in other words close enough to be the same. If you think about it for a moment, the reason becomes clear. The diaphram is the part acted apon by water pressure to keep the reg depth compensated. To do that accurately, the diaphram has to be of a certain surface area reguardless of who makes the reg or it's overall design, therefore the diameter of all regs has to be the same, otherwise they would not track the same as depth increased.

I don't see why the size matters at all. As long as the diaphragm has the same surface area on both sides (in the IP chamber and the ambient chamber), any increase in ambient pressure will be met by an equal increase in IP. That's depth compensation.

 

[divad]

. The later Zeagles are externally different and some have a modified internal design but if you look past the "style" changes you will see the same basic design..

Is the diaphragm crimped on both sides in the Apeks, or is this a "style" change like the soft HP seat?

 

[LeadTurn_SD]

Is the diaphragm crimped on both sides in the Apeks, or is this a "style" change like the soft HP seat?

I struggling to remember how / if my Flathead VI's differs from my Mares MR22 and MR12 as far as the seating surfaces for the diaphragm.... it has been over a year since I serviced a Flathead VI.... a little more recently for a Mares....

I thought that in both cases the diaphragm "sits" on a narrow, flat "ledge", and the diaphragm clamp ring has a smooth, matching surface that compresses (crushes?) the edge of the diaphragm as you tighten the clamp ring. Is this what you mean by "crimped on both sides"?

I looked in other manual I have (Apeks & Aqualung), and they do state something like "install a new diaphragm" in their reassembly instructions; but omit the "or you will die" statments that Zeagle uses

I guess it comes down to whether the "set" the diaphragm takes would prevent adequate "holding" grip the next time it is used..... since the diaphragm fits pretty tightly in the space provided, and is held down by the spring, I don't think it is going to shoot out of the first stage if it does not hold as securely....

In the troubleshooting sections of most of the repair manuals, it lists "worn diaphragm" as a cause of air leaking from that area of the 1st stage....

I'm guessing that in the event a diaphragm did "slip" in the fashion Zeagle warns about would probably happen when the air is first turned on, and would result in an air leak. Could it happen during a dive? I guess, but it seems like when the regulator is first pressurized would be more likely.

After all this, have any of you ever heard of a failure of a first stage diaphragm?

Best wishes.

 

[skankpile]

wow I'm surprised Zeagle has not chimed in yet.

 

[JBRES1]

wow I'm surprised Zeagle has not chimed in yet.

Check this out: I'll probably die for doing this...

Viddler.com - zeagle F7 diaphram replacement - Uploaded by undertaker

Point is: its so easy to replace I may do it next time I order parts; I figure I'll pop one in and check the IP as its cheap insurance I guess...

I may be missing something here, but aren't we talking about the internal diaphragm on that 1 st stage.
On my diaphragm 1 st stage regs there is a black diaphragm on the inside of the reg.
The diaphragm shown being replaced in the video is in Dive Rite speak the ICE KIT,
in HOG its the COLD WATER KIT, and in Scubapro its the DRY AMBIENT PRESSURE CHAMBER SEAL.
To replace the diaphragm on all of my regs you need to break the reg down.

Also as a side note I was taught to replace the outer diaphragm with the reg under pressure. Something to do with the ip , can't remember.

Jim Breslin

 

[LeadTurn_SD]

"Bubba, hold my beer while I make this here regulator repair video..."

No offense to whoever originally filmed the video, and please tell me it was nobody in this thread .... but they need to step away from the repair bench before they hurt themselves!

1.) That was the evironmental diaphragm, not the main diaphragm we've been talking about.

2.) AND, the enviromental diaphragm needs to be reinstalled with the regulator pressurized in order to work properly!!! Did you see it balloon upwards when the regulator was turned on? It is supposed to lie flat when the reg is pressurized, and actually be slighlty concave with the regulator unpressurized. The person in the video incorrectly installed the environmental diaphragm.

Don't dive the reg if it is like the one in the video, it is improperly assembled, and will not work properly. To fix it is easy (and there is no charge for this advice), remove the environmental diaphragm again, pressurize the reg, replace the environmental diaphragm, replace the screw on cover securely, depressurize the reg, and now watch the environmental diaphragm "suck in" a little. Now you can dive it. :blinking:

Sorry, end of rant.

Environmentally-sealed diaphragm first stages have two diaphragms:

1.) The outer one that was shown in the video. It seals the ambient chamber. The little plastic piston-thingie? That is the "transmitter", it transmits changes in ambient pressure to the.... wait for it....

2.) Main diaphragm. To acess the main diaphragm, you'll need to remove a retaining nut, the spring, and then the diaphragm clamp ring... which will require honest to gosh tools, compressed air is helpful to blow out the diaphragm without damaging the sealing surfaces....

Ok, back to our regular programming.

Best wishes.

Edit: skankpile, I just realized when I reread my post that it sounds like I'm directing my "rant" at you, and I'm not at all, just at the video you linked. Don't dive with your regulator in the state shown in that video... it was incorrectly reassembled. If you do decide you want to service your own Zeagle regs, ask questions here first... they are very easy to service, but there is a "bit" more to it than that video.

 

[herman]

Nice final touch on the video, dropping the octo on the floor, the mark of a true professional.

 

[DA Aquamaster]

This must be fairly recent, as the MK16/18 kits that I've used (it's been a few years) did not include the diaphragm, or my memory is really tanking.

Anyhow, the diaphragms are pretty hefty and they never experience HP air. I've pulled a few out of doublehose regs that were decades old and still surprisingly pliable.

The old Mk 16 and 18 kits never had them.

The Mk 17 kits have always had both the main diaphragm and the outer dry ambient chamber diaphragm, and the current Mk 16/18 and Mk 16/18 Update kits have them.

I've noted the Scubapro diaphragms are thinner than the traditional USD divers/Aqualung/everyone else who copied it diaphragm. Consequently while I agree a diaphragm in a 30 year old Conshelf is probably still good to go, It will take a couple decades before I will be comfortable saying the same thing about the Mk 16/18/17/19 series.

The outer environmental seal is much lighter and more flexible and I think it is important to replace it annually. If it leaks there would be no immediate impact, except in very cold water, but over the long term, in salt water, it would be difficult to rinse the ambient chamber through a pin hole leak - especially since the diver will be un aware of the leak and of the need to rinse the reg.

I am still waiting to have a reg come in where this has happened, but I expect the corrosive results to be truly spectacular. The good news there would be that the affected parts would be replaceable and not inordinantly expensive. But it's still worth replacing the old one annually and then keeping it for a spare. And I think that logic applies equally to any external environmental seal.

 

[divad]

Nice final touch on the video, dropping the octo on the floor, the mark of a true professional.

And done with such insoucience.

 

[divad]

I thought that in both cases the diaphragm "sits" on a narrow, flat "ledge", and the diaphragm clamp ring has a smooth, matching surface that compresses (crushes?) the edge of the diaphragm as you tighten the clamp ring. Is this what you mean by "crimped on both sides"?
QUOTE]





OK, I've got a Zeagle DSV open and in my hand;

1. The diaphragm sits on a narrow "ledge" with a "ridge" in the middle of it.
2. The clamp-ring has a smooth surface with a slot in it, ie, the obverse of the ridge.
3. So you have ridge fitting into a coresponding slot (or trying to).



Thanks for causing me to look at it more closely. I've got an IP gauge on it now. Later I'll flip the diaphragm over and see what happens. How about that?