Abstract: An induction heater is provided which has an electrical conductor (40) extending along an axis B. At least one solid heating element (43) for contacting and transferring heat to a material to be heated extends radially from the axis B and is formed of electrically conductive and preferably ferromagnetic material. An alternating electric current is supplied to the electrical conductor (40) to induce an electric current in a closed loop defined by a surface layer of the or each heating element (43) to generate heat therein. Induced eddy currents are confined to a surface layer due to the skin effect. The radial and axial thickness of the heating elements (43) is greater than twice the skin depth of the electrically conductive material at the frequency of the alternating electric current. Preferably the heating element (43) is in the form of a screw arranged on an electrically conductive heating member (42).

Abstract: An induction heater for heating a material is described which has an alternating current carrying conductor 30 extending along an axis of rotation. Mounted about the axis are containers 32 which rotate about the axis and hold the material to be heated. A core 34 is provided encircling the alternating current carrying conductor 30. The core 34 guides the magnetic flux resulting from an alternating current flowing in the conductor 30 to induce a current in the inner sleeve 38 between the conductor 30 and core 34. Current flowing in the inner sleeve 38 is conducted to end plates 40 and 42 and through the containers 32. The containers 32 are heated by the electrical current induced by the magnetic flux in the core 34.

Abstract: A heated rotor is provided to heat and circulate a substance comprising a shaft and at least one electrically heated rotor member supported on the shaft. The rotor member comprises an outer electrically conductive casing and at least one inner electrical conductor, electrically insulated from the casing. The or each inner conductor is electrically connected to the outer electrically conductive casing at an unsupported extremity of the rotor member. The shaft provides separate electrical connections to the or each inner conductor and the casing to enable an electric heating current to flow in the inner conductor between the or each unsupported blade extremity and the shaft.

Abstract: An induction heater comprising an alternating-current-carrying conductor (1) extending along an axis; a plurality of core sections (3, 4, 5) arranged in line and each substantially encircling the axis to guide magnetic flux resulting from the alternating current in the conductor (1); a plurality of heating element sections respectively associated with the core sections and each comprising an electrically conductive closed loop encircling magnetic flux in the associated core section (3, 4, 5) and being heated by electrical current induced thereby; and means (13, 14) to at least partially saturate at least one (4, 5) of the core sections thereby to reduce the coupling between the conductor (1) and the heating element section associated with said one core section (4, 5) and thus control the heating effected by said one core section (4, 5) and its associated heating element section (FIG. 4).

Abstract: The simultaneous heating and mixing of a fluid in a vessel with heated walls and a stirring device can lead to excessively high temperatures at the walls due to the formation of a thick boundary layer. This specification discloses a stirring paddle incorporating a heated element and mounted on a rotatable shaft. The heating element is connected in series with a rotor winding mounted on the shaft so that, when the shaft rotates, a heating current flows through the heating element.

Abstract: An induction heater has a conductor loop (1) in which a large alternating current is induced by a toroidal primary transformer (8). An annular secondary magnetic core (4) encircles a straight length of the conductor loop (1) and is itself enclosed by inner and outer cylinders (2 and 5) interconnected by annular end plates (6 and 9). The current in the conductor (1) produces magnetic flux in the core (4) which in turn produces axial heating currents in the cylinders (2 and 5). The inner cylinder (5) may have heated fins (3). An alternative embodiment has an inductively heated screw.

Abstract: Wire is made by cold working rod made from continuously cast silicon-killed boron steel made in an electric furnace from a charge of essentially 100% cold scrap.