The Heroult furnace, the best known in the arc class, and the Kjellin and Roechling-Rodenhauser fur- lc naces, the best known of the induction class, will serve as examples.
The Kjellin furnace consists essentially of an annular trough, AA (fig.
The molten metal in the Kjellin trough forms the " secondary " circuit.
Like the Heroult furnace, the Kjellin furnace may be lined with either magnesite or chromite, and it may be tilted for the purpose of pouring off slag and metal.
The shape which the molten metal under treatment has in the Kjellin furnace, a thin ring of large diameter, is evidently bad, inconvenient for manipulation and with excessive heat-radiating surface.
It is in the metal in these channels and in that part of the main mass of metal which immediately adjoins the coils that the current is induced by means of the coils and cores, as in the Kjellin furnace.
The normal use of the Kjellin induction furnace is to do the work usually done in the crucible process, i.e.
- Kjellin Induction Electric Steel Melting Furnace.
The Kjellin, can be used to replace the crucible melting process (§ 106), chiefly because their work is cheaper for two reasons.