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  1. #1
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    fusible plug on absorption cooling unit


    Hi, everyone, i am new here. According to CSA requirement:" 1.10.2 A system, unless constructed so it will not
    burst due to expansion of the refrigerant when subjected
    to abnormal outside temperatures, such as those
    generated by a fire, shall be protected by one of the
    following types of pressure relieving devices:

    a. A safety valve having a 1/4-inch (6.4 mm)
    outlet;

    b. A rupture member having an outlet not less
    than 1/16 inch (1.6 mm) in diameter; or

    c. A fusible plug having a maximum fusing point
    of 280 F (138 °C) and an outlet not less than
    1/16 inch (1.6 mm) in diameter. "

    We are following the C option. Consul and dometic are doing in different ways.Can anybody explain how to do this? Our questions:
    1, When to weld the fusible plug into cooing unit? Before or after passivation/ painting?
    2, if before passivation, will the oven temperature melt the alloy?
    3, If after passivation, how to treat the pipe inside of fusible plug?



  2. #2
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    Re: fusible plug on absorption cooling unit

    Absorption chillers should incorporate a bursting disc

    here's a link http://www.bsb.ie/Rupture_Disks/Reve...s-77-1006.html
    I'm back on the Pale

  3. #3
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    Re: fusible plug on absorption cooling unit

    Also you can not weld a fusible plug, it will melt and become a welded hole.
    Last edited by Brian_UK; 29-06-2009 at 11:48 PM. Reason: Dumb spelling...
    Brian - Torquay, Devon, UK
    I have to stop saying "how stupid can you be?" to my co-workers.
    They're starting to take it as a challenge...

    BASIC MAINTENANCE. If it doesn't move and it should then use WD40. If it moves but it shouldn't then use Duct Tape.

  4. #4
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    Re: fusible plug on absorption cooling unit



    2. CSA requirement:

    “1.10 SEALED ABSORPTION SYSTEM

    1.10.1 The manufacturer shall present evidence,
    acceptable to the testing agency, that the burst strength
    of the self-contained refrigerant system is not less than 5
    times the maximum working pressure determined at an
    ambient temperature of 110 F (43.5 °C).

    1.10.2 A system, unless constructed so it will not
    burst due to expansion of the refrigerant when subjected
    to abnormal outside temperatures, such as those
    generated by a fire, shall be protected by one of the
    following types of pressure relieving devices:

    a. A safety valve having a 1/4-inch (6.4 mm)
    outlet;

    b. A rupture member having an outlet not less
    than 1/16 inch (1.6 mm) in diameter; or

    c. A fusible plug having a maximum fusing point
    of 280 F (138 °C) and an outlet not less than
    1/16 inch (1.6 mm) in diameter. ‘
    3, Our questions.

    See the above illustration and CSA requirement. Consul is using “fusible plug” as the illustration. We are planning to do the same.We have some questions regarding how to implement this requirement.

    3.1 When to weld this plug into the cooling system? Before the passivation and electrophoretic painting? The absorption system should be baked in an oven prior to filling to complement the inside surface passivation at temperature 230°C for 12 hours. If welding the plug before passivation, the plug alloy would melt..

    3.2 If we weld the fusible plug after passivation and electrophoretic painting, then the inside surface of the fusible plug would not be passivated. And the welding would also damage the inside passivated surface of cooling tube coil a little bit. Furthermore, the fusible plug with anticorrosion paint would not look so nice like electrophoretic paint..

    Could you help us to understand how to produce the absorption cooling system with such fusible plug?


  5. #5
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    Re: fusible plug on absorption cooling unit

    Fusible plugs are normally screwed in not welded.

    Why go for the difficult choice?
    Brian - Torquay, Devon, UK
    I have to stop saying "how stupid can you be?" to my co-workers.
    They're starting to take it as a challenge...

    BASIC MAINTENANCE. If it doesn't move and it should then use WD40. If it moves but it shouldn't then use Duct Tape.

  6. #6
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    Re: fusible plug on absorption cooling unit

    Hi,Brian, thanks for information.
    Srewed solution is patented by Dometic and also related to charging method.
    We are tying other alloy. Let us see if we can solve this problem. Thanks

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