exploding cylinders

[tom]

Originally Posted by Woz

If you huff a pony dry water can easily get into it- this happened with one of our club pony cylinders- luckily in fresh water- and it almost filled right up.

How does that happen then? O ring ceases to be a seal once it's not pressurised, or what?

[Steve S]

Scary stuff indeed, although I did read with interest the Stoney cove interviewee saying ''clearly, the current inspection period of 30 months for diving cylinders is grossly ineffective and should be reduced as a matter of urgency before somebody gets hurt''

And on the back page the sad news for Grandude and 7 of Fi is that the diverlog member entrance fee is going up to £10 from the 1st January
(although I was there on the 2nd and was charged £8]

Safe diving,
Steve

[Woz]

Originally Posted by tom

How does that happen then? O ring ceases to be a seal once it's not pressurised, or what?

Dunno. It was strange. Kev (bottle monkey) huffed one dry in Stoney and I assume went deeper again on his back cylinder.

The pony ended up proper full- not just a bit of water but there must have been 2.5 litres in there. It was a bit strange.

[Twinsetmad]

Originally Posted by dlegros

Perhaps AP should look at a one-way valve system in the DSMBci?

If you were to put a check valve in....you could put air into the crack bottle and wouldn't be able to let it out....?

We could always swap to Ali cylinders...they don't rust.

[dlegros]

I was thinking of something after the valve connection on the SMB, but it sounds like it wouldn't work anyway looking at Woz's post.

Dom

[edward]

there is a non-return valve on the back of the pillar attached to the SMB. There is a metal post with a hole in where the gas escapes, and this is covered by a piece of rubber tube.

The one time I have got water in the mini-cylinder, it was because the piece of tube had become dislodged, and had allowed water back in. Easily fixed by moving it back again. If you get water in the bottle a lot, then got to be worth a check

[Shark Bait]

Personally I think there is plenty of room for improvment when in comes to checking and testing equipment (Cylinders especially) The only time I have come across dodgy cylinders was on holiday in Gozo, several of the cylinders our group used were leaking small amounts of air which we only noticed when we were in the water. The problem was not major but it outlines that even Diving holiday organisations (the people who should really be paying attention still don't always get it correct).

[scallop]

its better that the air leaks out slowly, is it not, otherwise it can hurt...boomboom....

(sorry couldnt resist it.....and I am bored.....)

[Okeanos]

I was talking to my LDS about the water from crack bottles or dsmbi bottles going back into the main cylinder, he reckons you'd have to leave it there for quite a while. For some reason emptying a cylinder underwater will cause it to fill with water, I've seen this happen to a mates 12L he was using on a sandlift!

Water and pressure will cause corrosion faster than anything, even worse with salt water. If its filled with any water in it, it will corrode very quickly, there's a lot more oxygen around for it!

Most likely causes are from compressors, although that's almost impossible as well, the water stack would have to be full first to allow water past it!

[Okeanos]

Just to add to the thread a picture I found somewhere.