Crucible Furnace Some More

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    CRUCIBLE FURNACE

    Crucible furnace is for the melting of non ferrous metals.

    Its capacity may range from 30 to 150 kg.

    The types of crucible furnace are:

    1)Pit furnace

    2)Coke fired stationery fur nace

    3)Oil fi red tilting fur nace

    4)Pot furnace

    1) PIT FURNACE

    The crucible is placed in a pit below the floor

    level, it is fired with coke.

    The charge to be melted is placed in crucible;

    coke is packed around the crucible. Natural

    draft is provided by a tall chimney.

    Many crucibles can be placed in a single pit.

    After the metal is melted, the covers are

    removed, the crucibles are lift out with the

    help of tongs and taken to pouring placed.

    This furnace is used for melting non ferrous

    metals.

    2) COKE FIRED STATIONERY FURNACE

    This furnace is used for melting non ferrousmetals in small quantity.

    This furnace is placed above the floor level.

    The crucible is placed in the heating chamber.

    The heating chamber is lined with refractories.

    Coke is used as fuel. Forced draft is used.

    A blower is used for supply of air.

    3) OIL FIRED TILTING FURNACE

    This furnace is used for melting non ferrous metals in small

    quantity and is fired by oil.

    This furnace is mounted on two pedestals above the floor level.

    For pouring the molten metal, the furnace is rotated by the

    geared hand wheel.

    Oil and air are admitted with pressure through a nozzle.

    The crucible is placed in the heating chamber and is heated by

    the flame.

    The furnace can be stopped whenever needed & temperature

    can be controlled easily.

    They give lesser pollution.

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    4) POT FURNACE

    Pot furnace is used for melting non ferrous

    metals like aluminum, magnesium, tin, lead etc.

    The pot is made up of cast iron or steel.

    The furnace may be fired by gasoline oil or

    coke.

    The molten metal is taken out of the pot furnaceby using ladles.

    Normally the capacity of pot furnace is around

    500 kg.

    ELECTRICAL RESISTANT HEATING FURNACE

    In resistance heating furnaces, the resistance heating elements are used to generate the

    heat in a heating chamber.

    The electrical resistance of an electrical element measures its opposition to the passage

    of an electric current.

    A heating element converts electricity into heat through the process of Joule heating.

    Electric current through the element encounters resistance, resulting in heating of the

    element.

    The heating elements used are Nichrome wire (80% nickel, 20% chromium), Kanthal

    wire (Kanthal is the trademark for a family of iron-chromium-aluminium (FeCrAl)

    alloys)or Graphite rods depending upon the temperature requirements.

    Metal charge is placed in a crucible or pot which is indirectly heated by heating

    elements.

    The temperature is controlled using thermostats and the temperature is monitored by

    thermocouples.

    The heating chamber is constructed by M.S. Sheets and channels and for thermal

    Insulation, fire clay bricks and refractory bricks are used.