What are cupola furnaces????

Hi THERE I am here again for your help  to your high school, college   assignments. Today we going to learn about the oldest furnace technology used in

Today we going to learn about the oldest furnace technology used in foundry.

THE CUPOLA

SCHEMATIC DIAGRAM OF CUPOLA

SCHEMATIC DIAGRAM OF CUPOLA

  • The most widely used furnace in the foundry for melting ferrous and non-ferrous metal and alloys. a cross section of a cupola is shown .
  •   A cupola is a shaft furnace of cylindrical shape erected on legs and columns . The     cupola shell is made of steel plate 8 or 10mm thick.
  • The interior is lined  with refractory bricks to protect the shell from overheating.the charge consist of fuel(coke as anthracite) fluxes(limestone used for decontamination of charge) and material (pig iron,scrap etc.)
  • Charging is mechanised by drop bottom buckets.
  • Air for combustion deliver through blowers. and enter into a chamber called wired box.
  • At the top of cupola there is there is a spark arrester to catch the incandescent dust and gases.

TUYERS are important part in cupola , they are the openings which extend through steel shells and refractory wall to the combustion zone.

    • A tap hole is provided to take out the molten metal.

A VIDEO FOR BETTER UNDERSTANDING 

DIMENSION OF CUPOLA

Cross section area of cupola is equal to:

A=   π *d^2 /4 =Q/Q1

d=clear diameter of cupola

Q=designed cupola output (in tonnes per hour)

Q1= specific output of the cupola (in tonnes per sq-m per hour)

As a rule = Q1=6 to 8

The cupola height is 3-5 times the diameter.

Height affects the melting rate , fuel consumption, and quality of molten metal

if too much height then coal is crushed under self weight.

if too small then molten metal is not heated properly thus reducing the output also.

Common dimensions are

OUTER diameter : 900-2700mm

INSIDE diameter :  500-2100 mm

HEIGHT : 12 m

FOR various  purpose design charts is shown

DESIGN SPECIFICATION OF CUPOLA

DESIGN SPECIFICATION OF CUPOLA

Various heat zone in cupola

  • COMBUSTION zone   :      The highest temperature developed in cupola furnace is in    this zone.                                                                                                                 1600-1700*C the reaction is exothermic :    C + O2 ———-> CO2  + HEAT
  • REDUCING zone: it’s above combustion zone up to height of initial coke bed.

The CO2 flowing upward reacts with  the hot coke  and reaction is  endothermic.

This zone application is to protect the metallic charge from oxidation due to its reducing

nature,    CO2 +   Coke —————> 2 CO(reducing agent)   – heat.

  • MELTING zone: This zone includes the first layer of iron above  the coke bed.

In this zone the charge starts to melt.

Also iron carbide formation take place.

3Fe   + 2 CO ————–>    Fe3C  +   CO2

  • PREHEATING ZONE: In this zone moisture,volatile materials are evaporated and the layers of charge are heated by outgoing gases and temperature here is about 1090*C.
A MICRO CUPOLA

A MICRO CUPOLA

IF YOU HAVE SOME QUESTION ASK ME IN COMMENT SECTION BELOW.

I AM ALWAYS HERE AS YOUR ASSIGNMENTS BUDDY……;)

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2 thoughts on “What are cupola furnaces????

  1. Hi dear sir
    This is mohiuddin and I am doing R&D on melting ferro alloys like silico manganes and ferro manganes size up to +3 to -20mm the melting point of this material is 1200 to 1250*C and I had taken taken some test trial on cupola furnace and its was successfully melted and i have few question on it what size of coke shall i maintain for +3 to-20 mm and still what level shall I maintain the charge level . Waiting for ur reply
    Thanks & Regards
    Mohiuddin

    Like

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