BOTTOM TYPE ELECTROMAGNETIC STIRRER FOR ALUMINUM
REVERBERATORY FURNACES |
Stirring action is extremely strong compared to other methods so
molten metal in all parts of the furnace is rapidly and evenly stirred.
The molten metal components are therefore uniform with no segregation
whatsoever occurring.
This unit is particularly effective for molten metal with high
alloy content such as magnesium, titanium and silicon. |
As the surface of the molten in reverberatory furnaces is 100-150°higher in
temperature than the bottom as it is sub1'eCted to radiation heat, thermal
absorption tends to become poor. However, as the molten metal and cold
charge are forced to touch when electromagnetic stirring is carried
out, the temperature of the surface drops within a few minutes as the
temperature of the top and bottom layer becomes uniform. Heat absorption
therefore increases and high energy saving effects are realized as heat
loss decreases. |
Heat conductivity of the cold material rises and the cold material
melts more rapidly as the molten metal is caused to flow by stirring.
The temperature of the overall molten metal drops at the same time with
increased absorption of radiation heat. In addition to energy saving,
the melting time is also therefore shortened. |
Prevention of oxidation in the molten metal is important to improve
yield.
Electromagnetic stirring reduces oxidation as it lowers the
surface temperature and, furthermore, it shortens the melting time.
Yield is also increased by the folding-in effect of the cold charge
into the molten metal. |
Although manpower or a special vehicle is required during the stirring
operation in
conventional stirring equipment, this type of operation is
entirely unnecessary with
electromagnetic stirring as operation is fully automatic. Also,
as there are no parts in direct contact with the molten metal, practically
no maintenance is required. |
It cannot be said that accurate temperature measurement of the molten
metal has been made even with temperature checks if the temperature
of the molten metal is nonuniform. However, accurate temperature control
w1'll be possible with the use of the electromagnetic stirrer as the
overall temperature of the molten metal will be uniform. |
Since heat absorption of the surface of the molten metal improves,
it will be possible to design furnaces with a deeper molten metal chamber
and a smaller surface area. This will then enable reducing the size
of the installation area. |
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Stirrer top |
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