furn

2. CUPOLA FURNACE

3. 3
CUPOLA FURNACE

4. ⚫Charge – the metal and fuel put into
the furnace. A charge is made up of
coke, iron, and limestone.
⚫Stack – where the charges sit until they
reach the melt zone.

5. ⚫Melt Zone- the area in the furnace
where the cold iron melts.
⚫Cast iron melts at about 2,700 degrees
Fahrenheit.
⚫Well – where the molten iron pools until
the furnace is ready to be tapped.

6. ⚫Wind Belt – distributes air evenly from
blower to all tuyeres.
⚫Tuyeres -openings in the furnace that
allow blast air to enter furnace

7. ⚫Slag Hole – hole in the back side of
the furnace where impurities are
removed from the metal.
⚫Tap Hole - hole in the front side of the
furnace where the molten iron is
removed.

8. 8
OPERATION/WORKING OF CUPOLA FURNACE
 Preparation of cupola
 Lightening of cupola
 Charging of cupola
 Melting
 Slagging and metal tapping
 Dropping down

9. 9
OPERATION/WORKING OF CUPOLA FURNACE
Preparation of cupola
 Unburned coke, slag and metal are removed from bottom doors
of previous melting
 Slag, coke, iron sticking to the side walls of the furnace are
removed
 Damaged bricks are replaced and damaged refractory lining is
patched up

10. 10
OPERATION/WORKING OF CUPOLA FURNACE
Lightening of cupola
 Soft, dry wood are placed on the sand bed
 Coke is placed above the wooden pieces till the tuyeres
 Wood is ignited through tap hole
Charging of cupola
 After the coke bed is properly ignited, the cupola is charged from
the charging door
 Involves alternate layers of limestone (flux), metal (iron) and fuel
(coke) up to the level of charging door
 Flux is a substance aiding in formation of slag for removing
impurities

11. 11
OPERATION/WORKING OF CUPOLA FURNACE
Melting
 A soak period 30 – 60 min is given to charge for preheating
 Blast is turned ON
 Coke becomes fairly hot to melt the metal charge
 Now molten metal starts accumulating in the hearth and appears
at tap hole
1 2
3
1. 1540̊̊ C - 1870̊̊ C 2. 120̊̊0̊̊ C

12. 12
OPERATION/WORKING OF CUPOLA FURNACE
Slagging and metal tapping
 After enough is accumulated the slag hole is opened and the
slag is collected in a container and disposed off
 The plug is knocked off from the tap hole and the molten metal is
tapped pouring into the mould
Dropping down
 As cupola heat charging is stopped, all the content of cupola is
allowed to melt till one or two charge is left above coke bed
 Now the air blast is switched off and the remains in cupola are
dropped down on the floor or collected in bucket

15. 15
CUPOLA FURNACE
Advantages
 Simple and easier to construction and easy to operate
 Low initial, operation and maintenances costs
 Less floor space
 Can operate continuously for many hours