Magnetic induction furnace with improved heating efficiency

Magnetic induction furnace configured to heat a solid or tubular metal billet made of non-ferrous material, said furnace comprising:

• a fixed body containing an electric motor having a fixed stator and an annular rotor movable in rotation around a longitudinal axis thereof in said stator, said rotor being integrally joined with a rotor body supporting a plurality of permanent magnets arranged so as to define a cavity having a longitudinal axis coincident with a rotation axis of the rotor and configured to contain the billet to be heated, by magnetic induction, by rotating the rotor and the joined rotor body, a rotation around a longitudinal axis thereof of said billet being prevented when the billet is disposed in the cavity, the plurality of permanent magnets comprising main permanent magnets magnetized radially in the rotor body and auxiliary permanent magnets magnetized axially around the cavity of the rotor, said main and auxiliary permanent magnets alternating in said rotor body around the cavity of the furnace;
• and
• wherein the main permanent magnets are polarized at 90° with respect to the polarization of the auxiliary permanent magnets, and wherein each of the main permanent magnets has an inner end part facing towards the cavity of the furnace and an outer end part resting on said rotor body, each of the inner end parts of the main permanent magnets is disposed adjacent to, and has the same polarity as, an inner end part of one of the auxiliary permanent magnets, and wherein the auxiliary permanent magnets have outer end parts spaced from the rotor body to form cavities in-between, respectively.