A zone of cupola furnace which starts from above the melting zone and extends upto bottom of charging door is known as:

Explanation:

Cupola Furnace:

• The cupola furnace is one of the most common types of furnaces used in foundries for melting ferrous metals and alloys. It is a vertical, cylindrical structure with various zones that facilitate the melting process. The zone of the cupola furnace that starts above the melting zone and extends up to the bottom of the charging door is known as the preheating zone.

Working Principle:

• The preheating zone of the cupola furnace plays a critical role in preparing the charge materials for the melting process. As the charge materials (metal scrap, coke, flux) descend through the furnace, they pass through the preheating zone before entering the melting zone. In this zone, the heat generated in the lower zones (melting and combustion zones) rises upward, preheating the charge materials. This preheating helps in reducing the energy required for melting and improves the efficiency of the furnace.

Characteristics of the Preheating Zone:

• Located above the melting zone and below the charging door.
• Primarily serves to preheat the charge materials using the upward flow of hot gases.
• Enhances the thermal efficiency of the furnace by utilizing the residual heat from the combustion and melting zones.
• Ensures that the charge materials are sufficiently heated before entering the melting zone, reducing the time and energy required for melting.

Additional InformationStack zone:

The stack zone is the uppermost part of the cupola furnace, located above the preheating zone. This zone primarily serves as a passage for the escape of flue gases and does not play a direct role in preheating or melting.

Well:

• The well is the bottom-most part of the cupola furnace, where the molten metal collects after melting. It is located below the melting zone and does not extend to the charging door.

Combustion zone

• The combustion zone is the part of the furnace where the coke burns in the presence of air to generate the high temperatures required for melting. This zone is located directly below the melting zone and does not extend upward to the charging door.