Has anyone else seen this happen?

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divezonescuba

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I have experienced this problem a couple of times from different manufacturers, so I do not think it is brand specific.

This involves a DIN nipple. There is the large 112 oring on the valve side and frequently, but not always a smaller oring 008 to 011 or so on the opposite end. The smaller oring seals against the regulator body.

What I have seen a couple of times is a malfunction where the smaller sealing oring somehow becomes deformed and enters the regulator HP area.

Sometimes this interfers with the internal components causing the regulator to fail in some manner. In one case, this happened to a new first stage that worked properly for a week and then suddenly started discharging hp air thru the low pressure ports. The oring was found in the regulator body preventing the diaphram regulator from functioning properly.

Just recently, I encountered a similar issue with a piston regulator. Only this time the malfunction was that the dislodged oring inside the regulator body blocked one of the high pressure ports from receiving air. This regulator had been functioning perfectly for 9 months prior to the problem.

I am curious, if anyone else has ever seen this?
 
Yes, on Atomics. I haven’t built enough Mk-20’s to see if the design issue is consistent.
 
I have experienced few times when I was installing the DIN stem(Apeks) to the main body. The o-ring popped out and was damaged as I screwed it up. Instant leak when attached to the tank and the valve was opened.
 
Yep! Here's an example:
20210610_190208.jpg

Atomic redesigned their yoke bolt to both decrease exposure to high pressure oxygen and prevent this.

Below you'll see another problem (manipulation of the yoke body after pressurization), but you can see the center raised boss that prevents o-ring movement in the newer yoke bolt design.
20170711_162021.jpg


Hate to say it, but it's usually operator error during installation. It's why mfrs specify holding the yoke or DIN bolt upright and threading it up into the body, so the o-ring doesn't slip out of position before it's compressed.
Alternatively, a bolt that loosens but still seals will allow o-ring movement. You'd think that tank pressure would blow it back out to the edge and seal, but probably something akin to Venturi flow effects sucks it into the HP flow path. Believe it or not, the reg in the top picture above actually sealed. You can see the lube in the picture. Almost all mfrs recommend no, or only trace lube on this connection. Don't help this oring be slippery.
 
Yep! Here's an example:
View attachment 671252
Atomic redesigned their yoke bolt to both decrease exposure to high pressure oxygen and prevent this.

Below you'll see another problem (manipulation of the yoke body after pressurization), but you can see the center raised boss that prevents o-ring movement in the newer yoke bolt design.
View attachment 671253

Hate to say it, but it's usually operator error during installation. It's why mfrs specify holding the yoke or DIN bolt upright and threading it up into the body, so the o-ring doesn't slip out of position before it's compressed.
Alternatively, a bolt that loosens but still seals will allow o-ring movement. You'd think that tank pressure would blow it back out to the edge and seal, but probably something akin to Venturi flow effects sucks it into the HP flow path. Believe it or not, the reg in the top picture above actually sealed. You can see the lube in the picture. Almost all mfrs recommend no, or only trace lube on this connection. Don't help this oring be slippery.
Yep, exactly like that one, only titanium.
 
RSingler pretty well covered it. I have not seen this problem on SP 1st stages except when the yoke or DIN retainer comes loose when the reg is pressurized. Then the o-ring can extrude into the opening created by the loose retainer. One way this typically happens is when someone grabs the tank by the regulator and pulls, rotating the regulator counter clockwise while the retainer is held tight by the pressure on the threads in the valve.

In fact, you can sometimes remove a sticky DIN retainer using the tank as a holder if you need to and don't have the proper tools. I wouldn't recommend it but it does work. Of course it ruins the o-ring.
 
https://www.shearwater.com/products/perdix-ai/

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