induction type furnace

 induction type Furnace 

Introduction 

Furnace is an enclosed structure in which material can be heated to very high temperatures, e.g. for smelting metals.
Or an appliance fired by gas or oil in which air or water is heated to be circulated throughout a building in a heating system. Here in this tutorial we describe about induction type furnace .

Types of  induction furnace 

Various types induction furnace
1. Core type induction furnace
2. Vertical  core type induction furnace
3. Indirect core type induction furnace
4. Core less induction furnace

1. Core type induction furnace 

The core type induction furnace is a just like transformer having primary connect to the supply and charge to be heated as secondary.


It consists of an iron core cu risible of some insulating material and primary winding connected to an AC supply. The charge is kept in the crucible. Which forms a single term short circuited secondary circuit? The current in the charge is very high of the order of several thousand amperes.

Disadvantage of core type induction furnace 

• As magnetic coupling between primary and secondary circuit is poor. Therefore leakage reactance  is high and power factor low.
• If normal frequency supply is applied for operation of such furnace the electromagnetic forces causes severe string action in the molten metal show low frequency supply.

2. Vertical core type induction furnace 

In this furnace a vertical channel employ instead of horizontal channel for the charge.
The output of this furnace depends on the types of dimension of the channel used. Like V shape channel as in this furnace used.

Advantage of vertical core type furnace

• Highly efficient heat
• Low operating cost
• Accurate temperature control, uniform costing reduced metal losses and reduction of rejects.

3. Indirect core type induction furnace

In such a furnace an inductively heated element is made to transfer its heat to the charge by radiation .
In this type of furnace the principle of induction has been utilized for providing heat treatment of metallic and other charges. It consist of an iron core linking with the primary winding and secondary winding also. In this case secondary consist of metal container. Primary winding is connected to the AC supply inducing current and heating the metal container. Heat is transmitted to the charge by radiation.

Advantage of indirect core type induction furnace 

• The Temperature control without used to external control equipment.
• Furnace temperature between 400 to 1000dgree Celsius according to needs.
• Its power factor is also poor .8 approximately

4 core less indurnace

The furnace consists of an external cylindrical steel shell hinged at the bottom to facilitate tilting of furnace during pouring.
The inner surface of the shell is covered with an insulating material made of asbestos, mica, while the bottom surface is covered with refractory bricks.