Abstract: An induction heating apparatus that can operate at current frequencies of greater than 60 Hz and at least 1 kW. The induction heating apparatus includes a high frequency power supply, a superconductive induction coil, and a fluid cooling system. A fluid cooling system is designed to cause a cooling fluid to flow at least partially about and/or through the superconductive induction coil.

Abstract: An induction heating and melting system uses a crucible formed from a material that has a high electrical resistivity or high magnetic permeability, and one or more inductor coils formed from a wound cable consisting of multiple individually insulated copper conductors to form an induction furnace that, along with its associated power supply, provides a compact design. The system components are air-cooled; no water-cooling is required. The crucible may alternatively be shaped as a tunnel or enclosed furnace.

Abstract: This invention relates to a device for melting or refining glass or glass ceramics. According to the invention, such a device is provided with the following characteristics: a channel which is arranged in an essentially horizontal manner and which is provided with an inlet and an outlet for the glass melt; and an HF coil for coupling HF energy into the melt is allocated to the channel. The channel is made of a plurality of metal pipes in a similar way to a skull pot. Said pipes can be connected to a cooling medium.

Abstract: An induction-heated furnace is disclosed. The furnace comprises a shell lined with refractory material and has walls and a floor. At least one induction heater is located in the floor of the furnace, the induction heater communicating with the interior of the furnace through a throat. The throat length is a substantial part of the service length of the induction heater. The invention also discloses structures in the induction heater throat that aids the distribution of molten metal in the furnace.

Abstract: An electrical conductor covered with an electrically insulating layer and which is required to conduct, for extended durations, a current under high external temperature conditions which can damage the electrically insulating layer, is provided with a thermal protection device for protecting the electrically insulating layer of the electrical conductor, for example, the conducting tubes forming the large inductors of an industrial electroheat furnace. The thermal protection device is formed from at least one layer of a composite refractory, produced as a combination of refractory fibers and a compatible refractory binder, to constitute a heat shield able to withstand external temperatures of between 500 and 1,600° C. Refractory tiles, which can vary in density, can also be provided on the outside of the composite refractory layer.

Abstract: A clamp assembly for securing a plurality of windings of an induction coil in a fixed position includes a T-shaped latch bar formed of high strength insulating material. The T-shaped latch bar has a stem and a cross member. The stem is secured to a second winding of three end windings, which preferably is located between the terminal or endmost winding of the coil, and the third winding, by a pair of stud bolts which are welded on the second winding. The cross member extends in an axial direction between the three windings. A pair of lugs are welded onto the terminal winding and the third winding. The ends of the cross member are formed with a pair of notches into which the lugs are seated for stabilizing the terminal winding and the adjacent two windings.

Abstract: A method and an apparatus for inductively heating a refractory shaped member provided with an internal space, particularly for a metallurgical vessel, enable as rapid, uniform heating of the shaped member as possible. An inner inductor is introduced into the internal space, the shaped member is heated from the interior by such inductor, and the inductor then is removed from the internal space.

Abstract: A heating assembly 1 for transferring liquid metal 28 has a closed cross-section and includes a refractory tube 4 wrapped in an insulating layer 5 which is in turn surrounded by an inductor 3 enclosed in refractory concrete within a metal shell, the insulating layer 5 consisting of an insulating refractory concrete layer 5a. The heating assembly 1 may be used in a liquid metal holding furnace 9 provided with a supply of pressurised gas Pr for producing metal parts.

Abstract: Electrically conductive tubing for realizing induction coils having improved efficiencies comprises an outer peripheral portion of conductive material defined by a plurality of side walls and a single hollow passageway. Each side wall has an inner and outer surface. At least one side wall has a curved outer surface. The hollow passageway is defined by the inner surfaces and can be either centered within the tubing or spaced apart from the center of the tubing. The present invention also defines an induction coil and an induction furnace having an induction coil which utilizes such tubing. The curved outer surface has a radius of curvature which is defined substantially by a function of the tubing width in the axial direction, and spacing between turns of the induction coil. The cross section of the outer surface of the outer peripheral portion of the tubing taken along a transverse axis of the tubing defines a geometric figure.

Abstract: An induction furnace which provides a controlled escape pathway for superheated metal is disclosed. The induction furnace comprises a base layer of refractory material in the bottom of the furnace vessel. The base layer of refractory is composed of a first refractory having a maximum operational temperature and a second refractory having a maximum operational temperature lower than that of the first refractory. At least a portion of the second refractory is arranged in a contiguous zone through the thickness of the base layer. The base layer supports a packed granular refractory lining that extends up along the side wall of the vessel. In one embodiment of the invention, the base layer takes the form of a means for pushing out the packed granular lining from the furnace. The pusher means is arranged for axial movement within the furnace in response to a driving force applied from below the base layer. The pusher means contains the contiguous zone of the second refractory.

Abstract: A magnetic yoke for an induction crucible furnace includes a rod-shaped core stack being suitable for carrying magnetic flux generated by a furnace coil of the induction crucible furnace. The core stack is enclosed on three principal surfaces thereof not facing the furnace coil by a flexurally and torsionally rigid support body having a C or U-shaped cross section. The support body is preferably formed of a material with good electrical conductivity and has longitudinal channels suitable for carrying a coolant. Preferably, an extruded profiled part formed of an aluminum alloy is used.

Abstract: A bushing cap used to close a gap in a liquid cooled bushing which surrounds a coil contained in a channel induction furnace. The coil, bushing and bushing cap is further surrounded by a thin refractory layer which is further surrounded by a molten metal loop. The bushing cap and bushing are liquid cooled to maintain a substantial uniform thermal gradient about the thin refractory layer surrounding the bushing and bushing cap. Preferably, this is accomplished by way of a bushing cap having a cooling member attached to a cover and mounted within the bushing gap. A cooling fluid is passed through both the cooling member of the bushing cap and cooling channels within the bushing to maintain a substantial uniform thermal gradient about the thin refractory layer.

Abstract: A cooling tube (T) is incorporated into each conductor (C1) of the coil. The current carried by this conductor is divided between the strands which are maintained in thermal contact with the tube even in transposition or twist areas in which the conductor undergoes particularly marked deformations. The conductor features at least one half-turn twist between the electrical terminals of the coil.

Abstract: A furnace for melting and melt-heat retaining of metals has two horizontal interspaced furnace vessels which form a melt chamber and each having a side wall facing the side wall of the other furnace vessel, each side wall having an opening horizontally aligned with the opening of the side wall of the other furnace vessel. A single inductor is positioned between these side walls and is formed by an integral block of ceramic having opposite ends abutting the outside of the side walls. The block has a transverse through-hole and two longitudinal through-holes straddling the transverse through-hole and open to the two furnace vessels so that they intercommunicate. The inductor has a core with an energizing coil and having a leg extending through the transverse hole. When the energizing coil is powered a melt in the two longitudinal through-holes is heated by an induced circuit which extends into and through melts in the two furnace vessels.

Abstract: A body of molten metal is simultaneously heated and rotated by the use of electromagnetic forces. In one embodiment, the melting of metals by induction heating is improved by using a circular spirally-wound electro-magnetic core located between a central flow channel and six peripherally-located flow channels. Three-phase electrical current is applied to the core windings to form a rotating magnetic field which intercepts the metal in the peripherally-located flow channels. The magnetic field causes heating of the metal in the peripheral channels with negligible heating in the central channel, thereby causing flow of heated metal through the peripheral channels to the bath. The magnetic field also causes rotational motion of the body of molten metal, thereby improving mixing and minimizing surface turbulence. In another embodiment, the electro-magnetic core is immersed in a body of molten metal to be surrounded thereby.