Ajax-Wyatt Vertical Core Type Induction Furnace

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Induction Heating Furnace

An electrical furnace in which the heat is produced by induction heating of metal, is called the induction heating furnace. The induction heating furnaces have the capacities range from less than 1 kg to 100 tons and are used to melt various metals like iron, copper, aluminium, etc.

Vertical Core Type Induction Furnace

The schematic diagram of the vertical core type induction furnace is shown in the figure below.

The vertical core type induction furnace is also known as Ajax-Wyatt Furnace.

  • This furnace has a vertical crucible instead of a horizontal one (as in case direct core type induction furnace) for the charge.

  • The shell of the furnace is made of heavy steel, and the top of the furnace is closed by an insulated cover which can be removed for charging the furnace. Therefore, the vertical core type induction furnace is convenient from metallurgical point of view.

  • In case of vertical core type induction furnace, the magnetic coupling is comparatively better and the power factor is also high. Therefore, it can be operated from the supply of normal frequency.

  • In this furnace, the molten metal is kept circulating round the vee-channel by convection currents. Since the vee-channel is so narrow that a small quantity of charge keeps the secondary circuit closed. Although the vee-channel must be kept of full of charge in order to maintain continuity of the secondary circuit.

  • The output of the vertical core type induction furnace depends upon the shape and dimension of the channel. Apart from the V-shaped channel, U-shaped channel and rectangular channel are also used in this type of induction furnace.

  • The weight of the charge in the crucible counteracts the tendency of the secondary circuit to rupture due to pinch effect (i.e. formation of bubbles and voids).

  • The inner surface of the shell is lined with some refractory material. The type of lining depends upon the type of charge to be melt. For example, the lining of clay is used for yellow brass, a mixture of magnesia and alumina or corundum is used for red brass and bronze.

Points to Note

Some of the important points related to Vertical Core Type or Ajax Wyatt Induction Furnace are as follows −

  • A hydraulic system is used for tilting the furnace for pouring out the metal.

  • The vertical core type induction furnace is suitable for continuous operation services.

  • When this furnace is operated from a normal supply frequency its efficiency is about 75%.

  • The vertical core type induction furnace comes in standard size that varies from 60 kW to 300 kW, and all are single-phase.

  • The vertical core type induction furnace is mainly used for melting and refining of brass and other non-ferrous metals.

Advantages of Vertical Core Type Induction Furnace

The chief advantages of the vertical core type induction furnaces are given as follows −

  • Vertical core type induction furnaces give consistent performance.

  • They have simple and accurate temperature control.

  • With the vertical core type induction furnace, we can obtain uniform castings, reduced metal losses and reduction of rejects.

  • The vertical core type induction furnaces have comparatively high power factor, ranges from 0.8 to 0.85.

  • They give highly efficient heat, low operating costs and improved production.

  • Vertical core type induction furnaces give local working conditions in a cool atmosphere with no dirt, noise and fuel.

  • The crucible is absent in case of vertical core type induction furnace.

  • There is absence of combustion gases resulting in elimination of the common source of metal contamination.

raja
Updated on 16-Mar-2022 05:06:49

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