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Where is the burst disk?

Discussion in 'Tanks, Valves and Bands' started by pisoiu, Jul 1, 2014.

  1. pisoiu

    pisoiu Solo Diver

    # of Dives: 25 - 49
    Location: Romania
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    I am using a 2x12 liters twins from BTS with this manifold+valves installed:
    Product catalogue : High Quality Diving Solutions

    Another 11 liter aluminium with this valve:

    Product catalogue : High Quality Diving Solutions

    I was unable to find any exploded view of those valves or details about this, so: where are the burst disks? Are there any?
    I am a bit concerned (maybe with no good reason) about overpressure. That's because I will go into a holliday in the next two weeks and I will carry the whole scuba toys with me, including cylinders. Because at the destination I won't be allowed to carry my cylinders with me in the room (nor I have the desire to do so), they will have to sit in the back side of the car for few days. They will not sit directly under sunlight but the car will do, so the temperatures inside may rise significant. Of course, I have no desire for nasty surprises....
     
  2. ajduplessis

    ajduplessis Solo Diver

    # of Dives: I'm a Fish!
    Location: dry land :-(
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    Not all valves have burst disc as is the case with the valves you have. Coming to think of it, I don't know of any of the newer European made valves with BD???
     
  3. widget

    widget Manta Ray

    # of Dives: 5,000 - ∞
    Location: South Africa
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    Indeed, as above those valves dont have a Burst Disk. Very few valves made for the European market have a burst disc now, and in many other countries (as here as well) its not a regulation.

    I doubt you will have any issues, I wouldn't worry about it.
     
  4. Akimbo

    Akimbo Lift to Freedom Volunteer Staff Member ScubaBoard Supporter

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    I believe it is the US DOT (Department of Transportation) that mandates burst disks here. I wish they would reconsider because I believe they are a greater risk to divers than the possibility of the tank exploding.
     
  5. Stoo

    Stoo NAUI Instructor

    # of Dives: 5,000 - ∞
    Location: Freelton & Tobermory, Ontario, Canada
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    I think they offer protection to the dude filling the tank, that falls asleep, or gets stuck on the phone... Once the tank is in the water, and being used, they become a hazard to the diver potentially, although I can't say I ever recall hearing about one failing while being used.
     
  6. Akimbo

    Akimbo Lift to Freedom Volunteer Staff Member ScubaBoard Supporter

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    I have "heard" of cases but they could have been sea stories. As the story goes, the divers were over-filling their tanks for deep dives off the New England coast when they started losing burst disks. So, they just stacked two copper burst disks behind the plug. Another story talks about Silver-brazing them shut.

    I have seen plenty of burst disks with small leaks though.
     
  7. pisoiu

    pisoiu Solo Diver

    # of Dives: 25 - 49
    Location: Romania
    108
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    Dunno... the protection for dude is in the compressor, it's the overpressure valve. I think all compressors have one. At least mine (coltri mch6) have one calibrated at 225 bar.
     
    the_dragon_no1 likes this.
  8. Hickdive

    Hickdive Solo Diver

    # of Dives: 1,000 - 2,499
    Location: Glasgow, UK
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    European specification cylinder valves, manufactured to EN250, do not have burst disks.

    Be VERY WARY of installing cylinder valves with burst disks into European cylinders. A valve with a burst disk is likely to be American and DOT spec and have a 3/4" NPS thread, a European cylinder will have an M25 x 2 neck thread. An American valve will appear to screw in to a European cylinder but will actually only be held by the last two threads and will burst them eventually.

    Burst disks tend to give way in hot cars because they are made of soft metal and raising their temperature will soften them whilst the air pressure in the cylinder rises due to heat. On the other hand, it would be very difficult to raise a cylinder's pressure to greater than test pressure and on to burst pressure just by the heat of the car.

    Remember temperature and pressure are in direct proportion in degrees Kelvin NOT Celsius.

    A cylinder filled to 200 bar and increased in temperature from 20c to 50c will only rise in pressure by around 21 bar, well within the cylinder's test pressure let alone pressure it might fail at.
     
  9. GrainDane

    GrainDane Angel Fish

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    Any cylinder used in the US is required by DOT to have a burst disk. The burst pressure cannot be higher than test pressure.

    Yes, burst disks do protect the fill-station operator. They also protect your vehicle or your home should the pressure in the cylinder reach a dangerous level. 3000 psi venting thru small holes in the burst disk will produce a loud, scary sound. however, the same cylinder exploding (because of doubling up or silver-brazing) will destroy your vehicle or cause massive damage to your home.

    don't mess with your burst disks!
     

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