Tank valve Thread O-ring failure

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moneysavr

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I just don't log dives
Well just to let you divers know,had a burst disk blow a few years back prior to a dive on dry ground with a supposed to be rebuilt vale that was not!

Now Yesterday as I was unhooking my video cam rig from 20' safety stop link on my anchor line -this was a solo dive and I had a back up pony live with its 2nd stage under my chin on a necklace,

The day started out high 80's and my tanks were kept in a cool place prior to dive,on searching 2 hrs "Mowing the lawn" on some poor/bad GPS no#s by a famous local wreck authority I decided to drop a marker on his no#s and lay out several hundred feet of scope and do a wreck reel grid search off the anchor just to see if a thermo Cline or silt may have obscured this wreck in the Bay of Green Bay Wisc,

I geared up let my video cam down my anchor line to the safety stop,sprayed my reg and hoses with a mild mix of Ivory soap used to lube my wrist seals on my dry suit and after a quick check =no leaks next to my dry bleed on the Sherwood reg I hit the water.

At about 18'FSW I was unclasping the video rig and checking things over for My decent to the bottom at 105'FSW when I had a push or force between my shoulder blades and heard the sickening sound of bubbles ! I quickly grabbed my main spg on my 130cuft HP tank and found the pressure at about 3400PSI and felt the loss was due to the cool down on the tank upon entry and it seemed to be holding,then I grabbed for my pony SPG on a 30AL cu-ft and found it read 3000 as it should and all the time I am saying Din-Din I should convert all to din thinking I had blown a yoke o-ring,I re hooked my video rig and watched as it slide down the line to the bottom as I had descended below my safety link,I added air to my wing and clipped my anchor tie off line=like a john line used to (safety tie off into a wreck) to a d-ring and anchor line as I as scened to the surface thinking if the leak or something blew or ruptured I would of rocketed to the bottom or off the anchor line !

Top side as I hit the surface I could feel the water and air splashing on my back and a look at my main SPG had me at less than 3000PSI I then switched to my pony reg for the quick swim along my tag line to the ladder,on the boat I took my rig off and found this see the photos,
1. Tanks were not in any way over heated,
2. tank was only 6 months new
3. took tank to a LDS for a vis and new oring and he had not seen this on a newer tank, and did not have a explanation next to the o-ring he replaced it with seemed less dense,or tank valve was not tightened properly at initial vis /valve installation
That said wow any thing can go wrong and to have back up air or a source of redundancy is a must have solo or buddy same lake /ocean diving!
By the way the tank leaked for about 40 mins till it ran down.

Dive safe,
Brad
Look at that o-ring ! so even your din valve tanks can go Opp's

100_2731.jpg
 
Is that a painted worthington cylinder?

I've had numerous extrusions just like your photo shows with the purple oring supplied on the new Thermo Pro valves. I believe it's a combination of the valve not being tightened completely (with a big wrench), the weak purple oring and the beveled valve oring seat. I've been replacing with standard buna or viton orings and bearing down on the valves and so far haven't had any repeat offenders. Hand tightening the valves (as typically done with aluminums) in the Worthington cylinders is not tight enough.
 
Thanks,

Its a worthington (Yellow)

I will replace my other one now too!
Thanks Mabe Worthington should know this? as I bet with a 3000PSI cylinder the o ring would work?
Thanks
Brad
 
WOW !!!!! I had the exact same failure yesterday ! I literally just walked in the door from picking up my tank after having the problem fixed. Another SB member familiar with my experience provided a link to this thread.

I brought home a brand spanking new Worthington X8-130 (not painted). It started leaking within minutes of bringing it home ... within in an hour of its first fill. It had the same purple O-ring material extruding out from between the valve and neck as in your pic.

I brought it back to the LDS this morning. They said that they have experienced several failures of this nature with tanks that have valves from Thermo Valve Corporation and use the special non O2 reactant material (called something like EPDS ????) which is an alternative to Viton (the purple stuff). They replaced it with a regular Viton O-ring. It's holding pressure just fine now. Here's a pic of the failed O-Ring that was removed from my tank.

IMG_0002.JPG
 
Puffer Fish:
EPDM is an old material is is usually black, the stuff above is new and for O2 usage.

Thanks Puff.
 
I was watching while diveriteexpress.com (Fill Express) put my new HP100 PST together. I believe it was Mark who - while he was putting the valve on the tank - explained that they didn't like the o-ring that came with the standard Thermo Pro valves, and he replaced it with one from his shop. This was back in January or February. (These guys are a class act - the knowledge they give freely, daily, is worthy of being in a book)

I wonder why TP continues to supply the o-ring if the feild knows to not use it?
 
riguerin:
WOW !!!!! I had the exact same failure yesterday ! I literally just walked in the door from picking up my tank after having the problem fixed. Another SB member familiar with my experience provided a link to this thread.

I brought home a brand spanking new Worthington X8-130 (not painted). It started leaking within minutes of bringing it home ... within in an hour of its first fill. It had the same purple O-ring material extruding out from between the valve and neck as in your pic.


WOW
That is strange and the tank was a X8 130, with about 45 fills in it since spring this year,
I will have to forward this to the Worthington rep as he post's on this board and seems to be on the up-and up with service .
PM and e-mail link sent to Mike at XS Sports a Worthington rep like to see his thoughts,
Just hope no one gets killed or bent, as it seems the leak was slow but,,,
Dive safe,
Brad
 
The material being used for that o-ring appears to be Fluorosilicone, which is a fairly new material that is highly recommended for O2 service.

There are a couple of major issues with using this particular
product:

1. It seems to always be blue in color, but it is available in a whole series of hardnesses, with only the very hardest being usable for high pressure tanks. Just looking at one, will not tell you if it is soft, medium or hard.

2. There are a lot of these being imported from China, but the hardness is not always stated.

The softer versions of the material are very elastic, which account for why the o-ring is only slightly damaged when extruded through a very, very tiny openning.

Unless one knows the actual hardness, would advise against using this material.

Note: The china product is very low cost, which might explain why it is being used a lot.
 
Wow,

I read this and found the following information the DOT site on tank failures:

http://hazmat.dot.gov/pubs/reports/cylinder/cyl.failure.analysis.reports.htm

I'm not quit sure how one would go about reporting the failure, but I would think that the DOT, or the http://www.cpsc.gov/ would want to issue a recall. Also, I would think that the LDS would have some sort of obligation to report this too. my .02

Thoughts?

<edit spell'n>
 
I also had this exact same failure with my new Worthington 130 tank. Took it in for the first fill after my first dive with it, and when I picked it up in the morning it was empty. The guy was sure he filled it hte night before, and investigation reavealed the o-ring had extruded sometime during the night.
 
https://www.shearwater.com/products/perdix-ai/

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