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Boiler Mounting - Fusible Plug

FUSIBLE PLUG

Function: 
Its function is to protect the boiler against damage due to overheating for low water level. It is fitted in the crown of the furnace or firebox at appropriate place.

Working: 
In the normal working conditions of the boiler, the fusible plug is fully submerged under water. This is so because under normal condition, proper water level is maintained & can be checked by water level indicator. Under the circumstances, the heat from the fusible plug is being conducted to water. This keeps the fusible metal at an almost constant temperature, much below its melting point. When the water level falls below the fusible plug, the plug gets uncovered from water. The upper portion of the plug gets exposed to the steam space. The steam cannot keep the plug cool. This will over heat the fusible metal. The plug falls down along with the fusible metal making a hole. The steam and water, being under pressure immediately reach the firebox and extinguish the fire.
Fig. - Fusible Plug


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Comments

  1. Anonymous23 August 2014 at 15:09

    Good one

    ReplyDelete
  2. Hazel Grace8 February 2020 at 05:52

    An early form of water-level indicator, now rarely used, consists of a float inside the boiler attached to a thin brass rod which passes vertically through a gland in the boiler shell.

    boiler cooling treatment service in Ontario

    ReplyDelete

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