Coz Tanks & O-Rings

[kelemvor]

When the OP asked about O-rings, how is it that some are now talking about CO? Two different issues. Perhaps start a new thread if you want to yak about the latter.

Someone briefly mentioned CO in post #6, then in post #7 the OP asked for an elaboration on that subject.

 

[MMM]

Someone briefly mentioned CO in post #6, then in post #7 the OP asked for an elaboration on that subject.

Oh, thanks. I missed that...

 

[Ray and Pam]

I thought orings were supposed to leak, isn't that how you tell you still have air in your tank?

 

[Hickdive]

HD...

True enough...for me...at hot beach destinations...I check everything the shop supplies like it was my own...especially valve ''O'' rings...if they appear to be worn/cracked/overly compressed...I remove them...clean the face of the valve with a Q-Tip...and replace them with one of my Viton ''O'' rings...

Christi's operation is not the norm...she's the exception...and operators like her are few and far between...

I've dove three quarters of the way around the world and back...and for every fully prepared/professional operator...there are ten that are so bare bones...if your not fully prepared for things like ''bad'' valve ''O'' rings...your going to be in trouble before you ever get started...

And...as far as letting a dive boat crew member ''tinker'' with any of ''my gear''...never happen...not to take anything away from good help...just my OCD...

You need to do your own prior planning...be familiar with everything you have...do all your pre-checks/servicing prior to gearing up on the boat...and have with you what you may need as far as spares/save your dive bits and pieces...there's no substitute for being properly prepared...

A thirty year old/fully functional Conshelf first stage...will do you more good than will a brand new $2000. titanium DIN first stage with a missing ''O'' ring that can't be immediately replaced...

You can store a lot of ''self help'' components in a spare mask box...tools included...

Where are all you former Boy Scouts...Be Prepared...

Best...

Warren

Jolly good, well said but none of that is relevant or a response to my comment.

 

[Cert1967]

@Christi - how does your company check the cylinder’s supplied to your customers for CO?

Likely the same way all operators check... they don't (and im not faulting them).

Have you ever seen an operator check tanks for CO (outside of sending samples out to a lab for general quality control)? In my limited experience I have not.[/QUOTE]

**************

Sure have - see photo from OCT2016 - The Odyssey, Chuuk Lagoon.

Captain Mike spoke for several minutes on the hazards on CO in response to a passenger's query.

Seems to me that a CO check/shutoff, prior to filling a cylinder would be a good idea.

 

[deepsea21]

Leak at the o-ring on the gauge end? I had that happen to me and my air pressure read several hundred pounds low. At first I thought I had used more air than normal.

Nope.. I've had that issue as well when that ring started leaking at the swivel point. These were little bubbles literally coming out of the hose itself at multiple points... looked a bit like a bubbling air stone in an aquarium. holes so tiny I couldn't see them.

 

[deepsea21]

Maybe learning to dive in the pacific in third world countries has made me somewhat blasé, but I've discovered that some of you Americans get real worried about a yoke o-ring bubbling underwater. It's a very common occurrence over this side of the globe.

It was a real surprise to me in Belize on one dive where the wifes o-ring had a small leak and every single diver in the group came over to "tell us" about it. Usually by grabbing my fin and making urgent animated pointing motions to alert me of the fact that there was this little stream of bubbles.

One woman even decided to 'rescue' my wife and I had to tear her hands off of my wife underwater. All meant well, but they all seemed freaked.

It is a very common occurrence and 99.99% of the time is not an issue. However, once you've experienced an issue, you'll not like seeing a tiny stream of bubbles emanating from that junction. Now, I wouldn't call a dive over it if I saw a tiny small stream emanating but having been there, done that and seen what can happen, my buddy and I would stay in closer proximity to each other throughout that dive than we normally would. Again, dive accidents happen because a number of factors and mistakes can come together at once from bad personal decisions made to ignored equipment issues. Until one can buy gill implants, we are entering a hostile environment that can kill us very quickly. I personally eliminate every and any issue under my control that presents risk regardless of how minimal that risk may appear to be. Diving is a incredibly safe pursuit given the risk/reward ratio if one strives to eliminate as may potential risks as one can.

 

[Griffo]

It is a very common occurrence and 99.99% of the time is not an issue. However, once you've experienced an issue, you'll not like seeing a tiny stream of bubbles emanating from that junction. Now, I wouldn't call a dive over it if I saw a tiny small stream emanating but having been there, done that and seen what can happen, my buddy and I would stay in closer proximity to each other throughout that dive than we normally would. Again, dive accidents happen because a number of factors and mistakes can come together at once from bad personal decisions made to ignored equipment issues. Until one can buy gill implants, we are entering a hostile environment that can kill us very quickly. I personally eliminate every and any issue under my control that presents risk regardless of how minimal that risk may appear to be. Diving is a incredibly safe pursuit given the risk/reward ratio if one strives to eliminate as may potential risks as one can.

But yoke o-rings can blow at any time. I've never seen anyone show that there's actually a relationship between a small stream of bubbles and an imminent failure. And what about the valve neck o-ring?

I just practice good buddy diving all the time, as many other failures and unexpected issues can occur at any time. That's also why I've barely dived since my wifes IPE, because I don't have another buddy I trust.

Anyway, i'm not saying its "good" to have an o-ring leak. And I wouldn't go into an overhead environment with one that leaked. But on a rec-depth tropical open water dive, it's certainly not something that should cause you to assault another diver underwater over.

 

[Prop Joe]

Think about it... ROUND O-rings sit in a square groove. Every time you apply pressure to them they "Squirm". When the rubber "squirms" over and over again they eventually fail due to the cyclic loads on the rubber. Simple solution is to use a square "Quad" seal that fits in the same square o-ring groove for less squirm. The quad seals do squirm but not nearly as much as a round o-ring.
I'm not sure what size the tank valve seal your operator uses but I have a few of these in different sizes in my save a dive stash...
McMaster-Carr

The Quad seals will leak before they blow. I've brought down thousands of these to Dave and Memo over the years. They work well. Make sure you get the right size though....

Edit: One other thing. Make sure you install the quad seal with a touch of silicone o-ring lube or they will be a bear to remove if/when they eventually fail.

 

[ReefHound]

Speaking of squirming, it helps a lot to get a good seal to turn on the air slowly. Opening fast is more likely to blow an 0-ring.