IndianTechnoEra: MPS1Unit2 [Foundry]

 

CUPOLA FURNACE

Cupola furnace is a melting device which is used to melt cast iron, bronze and other allowing elements in foundry furnace. It is the cheapest to convert pig iron into cast iron. In cupola furnace a low sulphur coke used of good quality.

PRINCIPLE

·         It works upon the combustion of coke which make carbon dioxide and heat and cause of this the iron changes into melt and drains down ward get melted.

·         When CO₂ reduce partially reduced again by consuming energy and coke with CO and CO₂ and supplied coke is present in the reaction equilibrium.

·         Finally, high concentration of CO is present in the exhaust gas and it can be extracted from the furnace.

CUPOLA CONSTRUCTION

STEEL SHELL - It’s two vertical cylinders of 6-12 mm thickness and 1-2 mm diameter. It’s height 4-8 times of the diameter. It is made of refectory brick and clay lining with silica and alumina (Sio₂ and Al₂o₃).

FOUNDATION - At the bottom of the shell exists bottom door in foundation through which coke, slag etc get discharge at the end of melting.

TUYERS [AIR PIPES] - It exists at 0.6-1.2 m above from the bottom foundation to provide the air for combustion of fuel.

WIND BELT - Wind belt is mounted on the other shell of the cupola which deliver air to the tayers.

BLOWER - Blower helps to enter the compressed air into wind belt so that air could enter in tayers.

SLAG HOLE - It is located at the middle and 250 mm down of the tayers for remove the slag.

CHARGING DOOR - Charging door exist at 3-4 m above tayers coke, flux and metal exist in charging door-

·         Coke: For burning and melt the material

·         Flux: Use limestone to remove slits of silage.

·         Melt: Metal

CHIMNEY AND STOCK - It located 4-5 m above the charging door use to remove useless air and gases and also existing of spark arm ester spark by which any charge particle return back into shell.

 

ZONES IN CUPOLA

MELTING ZONE - It consists with 1600^oC. It start from the top of coke and extend up to a height of arm    

3Fe + 2CO      -->         FeO + O CO₂

COMBUSTION ZONE - It exist at above the top of tayers around 150-300 mm.

C + O₂        -->          SiO₂ + Heat

Si + O₂        -->         SiO₂ + Heat

Mn + O₂     -->           2MnO + Heat

Fe + O        -->           FeO + Heat

REDUCING ZONE - It located at the middle of the melting zone and combustion zone. Where reduce CO2 to CO and temperature 1200^o.

CO₂ + C (Coke)  -->           2CO + Heat

WELL OR CUPRIC ZONE - It located at bottom of tayers and top of sand bed by which melted material remove.

CHARGING OR PREHEATING ZONE - For heat the cupola before the use of cupola.

STACK ZONE - Where returned charges exist.

WORKING PROCESS

Make cupola construction and dry before start burning. Clean slag around the Tuyers. Proper reappear the holes by silica and fire clay and supply air slowly. Then burn before 3 hour to use the required temperature. Use 3% flux, 10% steel and 50% grace certain flux remise the impurities protest the iron foreside. Leave to freeze for an hour and stop the air supplying. It can be use by 10 hours burn but not extend on melting proscenium.

ADVANTAGES OF CUPOLA FURNACE

• Simple in Construction.
• Wide range of material can be melted.
• Less floor space is required.
• Very skilled operators are not required. Can be easily operated by low skill person.
• Low cost of operation.
• Low cost of maintenance.
• Low cost of construction.

 

 

DISADVANTAGES OF CUPOLA FURNACE

• The main disadvantage is that sometimes it is very hard to control the temperature in this furnace.
• Metal elements are converted to their oxide which is not suitable for casting.

 

 

APPLICATION OF CUPOLA FURNACE

• It is mainly used to convert pig iron to molten iron.
• More types of cast iron are produced from this furnace like malleable and grey cast iron.
• The cooper base alloy is also manufactured by this device.

B1.1MP2CupolaFurnace