Abstract: An induction heater (14) for use in conjunction with an associated furnace (10) for material processing includes essentially straight induction coil (16, 50) arranged inside the furnace shell (12). The induction coil (16, 50) has an attachment end (32, 54) extending outside of the furnace shell through a first opening (40) therein. A replacement induction coil (54R) is selectively connected with the attachment end (32, 54) of the induction coil (16, 50) and slidably inserted into the furnace shell (12) whereby the essentially straight induction coil (16, 50) is simultaneously slidably pushed out of the furnace shell (12) through a second opening therein.

Abstract: An induction heater (14) for use in conjunction with an associated furnace (10) for material processing includes essentially straight induction coil (16, 50) arranged inside the furnace shell (12). The induction coil (16, 50) has an attachment end (32, 54) extending outside of the furnace shell through a first opening (40) therein. A replacement induction coil (54R) is selectively connected with the attachment end (32, 54) of the induction coil (16, 50) and slidably inserted into the furnace shell (12) whereby the essentially straight induction coil (16, 50) is simultaneously slidably pushed out of the furnace shell (12) through a second opening therein.

Abstract: A threading and scale removing device is disclosed which includes a heating apparatus having an inlet and an outlet. A work-piece is fed through the inlet and exits through the outlet. A plurality of rollers are operatively associated with the heating apparatus. A belt is mounted on the plurality of rollers and is adapted to rotate through the heating apparatus. As the belt rotates, it functions to thread the work-piece through the heating apparatus. Once the work-piece has been threaded through the heating apparatus, the belt functions to catch and remove metal scales that flake from the work-piece during heating. A motor is operatively connected to the plurality of rollers for driving the rollers and allowing the belt to rotate through the heating apparatus.

Abstract: A coil/capacitor combination useable as an induction furnace includes a reactive capacitor bank directly bolted to the coil and protected from coil fields by shields and heat sink plates. The coil includes a selectively openable switch for placing the coil assembly on and off of a moving strip. The switch is operated by deflecting coil turns within the natural resiliency of the turns themselves.

Abstract: An induction heating coil assembly including modular cast refractory blocks (10, 12, 14, 16) encasing copper turns (24, 26). The blocks are configured so that the segmenting between blocks occurs at locations where refractory cracks have been prone to occur. The turns, and additional support rods (42, 44), are placed in tension and fastened against the end walls of the refractory blocks to place the blocks under compression to the extent that normal gravitational forces tending to place the refractory blocks in tension are overcome by the compressive forces of the turns and rods.

Abstract: An apparatus and method for continuously casting molten metal, wherein the apparatus comprises first and second endless belts and first and second edge dam block continuous belts disposed to form a casting region wherein molten metal can be cast into strip. The edge dam blocks have a length longer than the endless belts to form catenaries spaced from the first endless belt. The edge dam blocks are inductively heated with induction heaters disposed in the catenaries to avoid temperature shock to the edge dam blocks during the casting and to minimize undesirable heat losses.

Abstract: An induction melting furnace includes a detection system for sensing metal penetration into a wall of the furnace depending upon detecting heat flow from the hearth to the furnace. The furnace includes a crucible including a refractory lining for holding molten metal, a coil for inductively heating the molten metal, and a power supply for supplying energy to the coil and the detection system. An electrode system is interposed between the coil and the lining comprising a sensing mat housing conductors receiving a test signal from the power supply, wherein the sensing mat includes a temperature sensitive binder that varies conductivity between the conductors in response to heat penetration through the lining. The sensing mat is preferably comprised of flexible phillosilicate mica for enhanced thermal conduction and the binder comprises an organic resin compound which carburizes at a predetermined elevated temperature.

Abstract: An adjustably dimensionable inductive heating apparatus includes inductor turns which are supported by a slide or actuator to allow selective positioning of the inductor turns to a variety of positions. The adjustable support members are disposed to allow the inductor turns to move in a relative width dimension or a relative turn spacing or height dimension. Flexible crossover connector cables accommodate turn repositioning without inhibition of inductor movement. Another feature includes selective length adjustment with the inclusion of a plurality of flexible crossover connectors including in-line switches for selecting which crossover connector cable will determine overall coil length.

Abstract: An energy-efficient power inverter is disclosed which changes direct current provided at a pair of source terminals to alternating current at load terminals. The power inverter comprises a switch device and snubber circuit including a resistance, a capacitance and a saturable core device for selectively removing the resistance from the snubber circuit. At saturation the core device effectively shorts the resistance out of the circuit, and upon coming out of saturation the device effectively reinserts the resistance for improved reduction in power losses during the switch operation.

Abstract: A channel furnace for the inductive heating of metal includes a molten metal holding hearth and a core and coil assembly surrounded by a channel of the furnace for inducing heating current in the metal in the channel. The channel is separated from the core and coil assembly by a refractory insulator and a bushing interposed between the refractory insulator and the core and coil assembly. The bushing is comprised of a wall portion having a plurality of slits or gaps disposed in the wall for minimizing eddy current formation therein and correspondingly reducing power loss therefrom. The bushing can be configured as either a coil type comprised of a plurality of slits disposed to extend circumferentially or a cage type, wherein the slits are disposed to extend longitudinally for segregating the wall into a plurality of wall sections. Both types can be made of water cooled flat metal tubes instead of plates with slits.

Abstract: An adjustable width transverse flux heating apparatus for induction heating in the moving workpiece includes first and second elements disposed in the common plane to form an inductive coil. The first and second conductor elements define a middle spacing in an internal cross-section area of the inductive coil. A monitor detects workpiece fractures and generates signals relating thereto. A motor system moves one of the conductor elements relative to the other in response to the signal generated by the workpiece monitor.

Abstract: The present invention provides a hot reversing rolling mill for isothermally reducing a metal strip product. The mill includes a hot reversing mill stand with a pair of coilers positioned on opposite sides of the mill stand. At least one heater is positioned between one of the coilers and the mill stand with at least one strip cooling unit positioned between one of the coilers and the mill stand. A sensor is provided for sensing a strip parameter indicative of strip temperature as well as a controller for controlling each of the heating and cooling units in response to the sensed parameter. The rolling mill of the present invention can be utilized for isothermally rolling multiple passes of a metal strip product on the hot reversing mill.

Abstract: A multi-furnace control system selectively delivers preselected percentages of available power to furnaces of the system, preferably designated as either a melt furnace or a hold furnace. The power supply delivers power to both furnaces. A capacitor station in parallel connection to the power supply and the furnaces is tuned to form a tank circuit therewith. Switches control the selected power delivered to the furnaces respectively and control the delivery of a first portion of the power for holding molten product in the hold furnace as the master control. A remaining portion of the power is then delivered for melting product in the melt furnace. The capacitor station acts as a reactive tank for both furnaces.

Abstract: A high frequency power inverter comprises a power supply, a thyristor for switching the energy from the power supply to a load and a neutral capacitor for storing energy cyclically to assure reverse voltage is applied to the thyristor. A clamp circuit is associated with the switch to limit the ring-up voltage on the capacitor to a preselected value. The clamp circuit is comprised of an inductor having a relatively large value for permitting a gradual leaking of the capacitor voltage during an inverting of the power supply voltage to the load so that the capacitor can ring-up to a higher value than the supply voltage. The inductor is selected so that under all conditions, the voltage on the capacitor will be safely larger than the power supply voltage plus a load voltage peak for a time long enough to assure thyristor turn off.

Abstract: Transverse flux heating assembly for inductively heating a moving strip includes opposite spaced J-shaped conductors to form an inductive heating coil. The coils define a middle spacing therebetween which is unobstructed by flux guides to permit free translation movement between the conductors in a direction parallel to the strip width. The inductors provide a fully adjustable coil width to accommodate different strip widths in the heating operation.

Abstract: A furnace refractory extraction system and method includes a selectively removable bottom portion which is attached to a refractory extraction device associated with a container for drawing the refractory lining of a coreless induction furnace into the container. A plug portion in the furnace bottom is selectively removable to provide access to a bottom wall of the refractory lining. An opening is made in the bottom wall of the lining through which an extractor shaft is inserted and then attached to the removable bottom portion of the furnace bottom. The other end of the shaft is attached to a piston and cylinder assembly associated with the container at the open end of the furnace. When the piston and cylinder assembly is powered, the lining is drawn into the container.

Abstract: An apparatus for galvannealing steel strip includes an applying device for applying a coating of controlled thickness of a strip. A controller controls the thickness of the applied coating. A heating furnace heats the steel strip to produce a galvannealed product. Edge heaters for heating the edges of the steel strip by magnetic induction promote uniform temperature distribution across the steel strip. The uniform temperature distribution produces more uniform galvannealing in the product. The edge heaters have preselected operating frequencies. A modulating circuit imposes a frequency modulation on the operating frequencies of the edge heaters to avoid undesirable transverse flexural resonance in the galvannealed product.

Abstract: An induction heating system is applied to a continuous molten metal casting apparatus having two endless flexible casting belts. The belts are arranged such that front surfaces of each belt faces the other belt and a pair of dam blocks arranged at the edges of one of the belts along with the belts themselves form a casting region. Molten metal is delivered to the casting region to form rectangular sheets of cast metal. Inductive heaters preheat the endless belts prior to the belts entry to the casting region. This preheating allows for continuous smooth casting.

Abstract: An induction strip heating assembly is provided having multiple induction coils disposed in coaxial tandem and including at least two coil power sources for generation of first and second inducing currents in the coils for the induction heating of a workpiece, such as steel strip, passing therethrough. It is a feature of the invention that the assembly includes a closed loop of electrically conductive material coaxially interposed relative to the induction coils and disposed for induction therein of a circulating current opposite to a one of the inducing currents whereby a magnetic field of the circulating current in opposition to an inducing magnetic field of the inducing current causes a reduction in net magnetic field strength on a side of the loop opposite of the inducing current. Such an assembly provides suppression of intercoil magnetic coupling so that the coils may be spaced adjacent one another with less space between them than would be required if no loops were used.

Abstract: An electric induction coil assembly for heating workpieces of varying lengths has a plurality of axially-aligned induction coils. The coil turns are spaced along the axis of the coil assembly where within the axial distance necessary for a first coil to complete one turn, a portion of at least one other coil is interposed between corresponding points of the first coil. The axial length of the energized coil assembly is controllable by increments of less than the pitch length of a coil.