Operation:-
First the drop door at the bottom is closed. Sand bed with slope towards tap hole is rammed. Coke bed of suitable height is prepared above the sand bed and is ignited through the tap hole. After proper ignition, alternate layers of charge, flux & coke are fed through the charge door. Then the charge is allowed to soak in the heat and the air blast is turned on. Within 5 to 10mins, the molten metal is collected through the tap hole. When enough metal is collected in the well of the cupola, the slag is drained off through the slag hole. Then the molten metal is collected in the ladles and is transported to the moulds with a minimum time loss.
Fluxes are added in the charge to remove the oxides & other impurities present in the metal. The flux commonly used is lime stone (CaCO3) in a proportion of 2 to 4% of the metal charge. Others fluxes used are dolomite, sodium carbonate, calcium carbide. Flux reacts with oxides to form compounds having low melting point and lighter so that it will float on the metal pool.
First the drop door at the bottom is closed. Sand bed with slope towards tap hole is rammed. Coke bed of suitable height is prepared above the sand bed and is ignited through the tap hole. After proper ignition, alternate layers of charge, flux & coke are fed through the charge door. Then the charge is allowed to soak in the heat and the air blast is turned on. Within 5 to 10mins, the molten metal is collected through the tap hole. When enough metal is collected in the well of the cupola, the slag is drained off through the slag hole. Then the molten metal is collected in the ladles and is transported to the moulds with a minimum time loss.
Fluxes are added in the charge to remove the oxides & other impurities present in the metal. The flux commonly used is lime stone (CaCO3) in a proportion of 2 to 4% of the metal charge. Others fluxes used are dolomite, sodium carbonate, calcium carbide. Flux reacts with oxides to form compounds having low melting point and lighter so that it will float on the metal pool.
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