Abstract: A core structure for induction heating apparatus consists of radially disposed core parts carrying cylindrical coils for energization. The core parts join the outer end to form a rim and at the center to form a central pole.

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: A raw egg is cooked by orienting the egg adjacent a field coil and electrically energizing the field coil with a high-frequency alternating electric current so as to inductive heating the egg. The field coil operates at between 1 MHz and 1000 MHz, preferably between 10 MHz and 50 MHz, and generates a field having parallel lines passing through the egg. The coil and egg are relatively rotated, normally by holding the coil stationary and rotating the egg, while electrically energizing the field coil. To this end the field coil has a pair of halves connected in series and flanking the egg.

Abstract: A getter heating coil assembly producing a focused magnetic field for heating objects in close proximity to the coil assembly. The coil assembly comprises electrical conductors wound on a coil bobbin, the coil bobbin having a central spindle around which the conductors are wound. The wound bobbin is assembled with a magnetic field concentrator, said field concentrator having a central core extending from a base, and a side wall extending from the base to enclose the wound bobbin. The central core of the field concentrator fits within the spindle on the bobbin and extends through it. The coil bobbin remains exposed on one side for emission of focused electromagnetic energy when alternating current is supplied to the coil windings. A button of high magnetic permeability material may be attached to the field concentrator for focusing the emitted electromagnetic energy toward the center of the coil.

Abstract: The processing time and energy efficiency of metal or composite bonding operations is improved by heating the lay-up preform of the structure in an induction heating press where energy goes primarily to heating the workpieces rather than to heating the tooling or being lost to the environment. The bonding process is especially beneficial for joining thermoplastic composites, but it also can be used with metals or thermosets. Preferential heating at the bondline is achieved by using shims to define the bondline and to define bead regions that have relief from contact with the susceptor envelope because of the thickness of the shims in the bondline regions.

Abstract: High frequency reactors for interconnecting a high frequency electrical power source and a load which reactors include a pair of plates having opposite surfaces with a length and width and a thickness between the surfaces which is small relative to the length and width of the surfaces. The plates are disposed with opposing closely spaced surfaces insulated from each other, and each of the plates has longitudinally aligned first and second portions with one portion of one of the plates electrically insulated from another portion of the plates and conductively interconnected by a variable reactance with another portion of the plates.

Abstract: A device for heating a press tool (4), which is mounted in a press (3) for manufacturing products wholly or partially of plastic or composite, consists of a core (1) of electric sheet steel, a coil arrangement (9, 10, 11) placed around the core (1), and a voltage source (12). The voltage source (12) is connected to the coil arrangement (9, 10, 11) for generating a magnetic field in and around the core (1). The core (1) has two poles (8a, 8b) which, between themselves, receive the press tool (4) and are displaceable in relation to one another for applying a press force to the press tool (4) and conduct the generated magnetic field into the press tool (4). A press (3) comprises such a heating device and is used in a manufacturing method where the press tool (4) is heated by the magnetic field supplied thereto.

Abstract: In a heating apparatus for the heating of a solid or fluid medium, several permanent magnets are arranged on the periphery of a rotor which produce a magnetic field in whose region an electrically-conducting medium is arranged. The magnetic field from the permanent magnets is radiated approximately radially. By rotation of the rotor, a relative motion arises between the permanent magnets and the electrically-conducting medium, and eddy currents are effected within the medium, thereby causing heating of the same. Electrically-conductive water can be provided as the medium to be heated. In this embodiment electrically-conductive water is fed through a helical conducting coil, with an inlet and outlet side arranged around the rotor in proximity thereto, and is connected to a line which feeds to a user from the outlet side and back to the inlet side in a closed cycle. With this heating apparatus, heat is transferred to the medium with an improved efficiency.

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: An induction heating roller apparatus comprises:a stationary shaft 23 having a plurality of hydraulic operating mechanisms 27 arranging in one line in the direction of axis, each hydraulic operating mechanism being made up of a cylinder 25 and a piston 26, and magnetic flux generating mechanisms 32 and 35 which comprise iron cores 30 and 33 and induction coils 31 and 34 wound on the latter 30 and 33; anda roller 21 which is rotatably supported on the stationary shaft 23, and has a cylindrical wall which includes jacket chambers 22 filled with a two-phase (gas and liquid) heating medium. In the apparatus, the magnetic flux generating mechanisms 32 and 35 being arranged on both sides of the stationary shaft in the direction of axis in such a manner that they are circumferentially 90.degree. away from the hydraulic operating mechanisms arranged in one line.

Abstract: An electromagnetic levitator is disclosed, comprising: a plurality of longitudinal sections formed from a conducting material and arranged around a longitudinal axis. The longitudinal sections are connected to a power source such that when the levitator is in operation, current flowing through adjacent longitudinal sections creates opposing magnetic fields. The levitator has first and second ends defining a levitation zone therebetween. When alternating current is passed through the conductors, a levitation tunnel is formed in the levitation zone, with the levitation tunnel having zero magnetic flux density along its center and non-zero magnetic flux density at all other points.

Abstract: A single turn induction heating coil provides a varied magnetic flux density for heating a portion of a load having a thermally and magnetically responsive sealant and tubing. The varied interior diameter of the cylindrical coil structure increases the magnetic flux density at the open ends of the coil or wherever desired, causing the ends of the magnetically responsive materials contained within the coil to be heated at a rate comparable to the middle portion of the coil. Consequently, the sealant and tubing recover faster and more uniformly avoiding the high incidence of tubing "flare up" or "flip back" common with typical single or multi-turn induction coil heaters. In the preferred application, heating produces a complete fluid block in a cable load section within the coil without overheating or damaging the load.

Abstract: An induction heating coil assembly for use in a roller induction heating line has a magnetic shunt for receiving a portion of an electromagnetic field generated along the axis of the induction coil and directing that portion along a path parallel to a workpiece passing along the heating line. This flux path ensures that eddy currents induced in the workpiece flow primarily perpendicular to the axis of the workpiece, and not along the axis of the workpiece where they could cause arcing between the moving workpiece and the conveyor rolls.

Abstract: An induction heating apparatus for heating continuous strip material. In a first embodiment, two coil sections each having a gap at one end for the strip material to pass edgewise into and out of the apparatus for heating wherein the coil sections are adapted for connection to two power supplies such that the first power supply connects through one half-turn of each of the coil sections, and thence to the second power supply, which is connected through the second half-turns of the respective coil sections and back to the first power supply, all in series. In a second embodiment, the coil sections are adapted for connection to four power supplies in series; each power supply connected to a respective half-turn of the coil sections, such that one half-turn is connected between each of the four power supplies. The series connection ensures uniform amplitude and phase of the electrical current applied to the induction heating coil apparatus.

Abstract: The linear motor pump for a wave soldering apparatus comprises in accordance with the invention several pumping channels arranged substantially parallel to each other and separate from each other. It includes preferably a multiply segmented stator. Each stator segment has one pumping channel allocated to same. By means of this a homogeneous pumping performance i.e. homogeneous pumping pressure distribution over a practically arbitrary width is achieved, which leads to a homogeneous solder wave. By the arrangement of the pumping channels and the design of the stator in accordance with the invention a turbulent whirling of the solder is made practically impossible.

Abstract: A temperature detecting apparatus, includes an excitation coil magnetically couplable with metal layer of a heater, the excitation coil being supplied with an AC electric energy; and a detector for detecting a voltage drop, across the excitation coil, which changes with temperature of the heater. The metal layer has a metal ring and the excitation coil is magnetically connected with the metal ring.

Abstract: The processing time and energy efficiency of metal or composite bonding operations is improved by heating the lay-up preform of the structure in an induction heating press where energy goes primarily to heating the workpieces rather than to heating the tooling or being lost to the environment. The bonding process is especially beneficial for joining thermoplastic composites, but it also can be used with metals or thermosets. Preferential heating at the bondline is achieved by using shims to define the bondline and to define bead regions that have relief from contact with the susceptor envelope because of the thickness of the shims in the bondline regions.

Abstract: A galvanizing apparatus comprising a vessel for containing a melt of molten metal. The vessel includes at least one conical projection in its side walls around which an induction heating coil is wound to generate a uniform and continuous stirring pattern of molten metal that penetrates deeply into the pot. In a second embodiment, the galvanizing vessel has no projections from its side walls, but comprises instead one or more flat inductors disposed on the exterior wall of the vessel. The flat inductor is surrounded by magnetic return shunts for directing the magnetic force field created by the inductor.

Abstract: Thermoplastic welding is an emerging technology targeted at significantly reducing the manufacturing cost of aerospace structure by eliminating fasteners and the touch labor associated with fasteners to prepare, install, and inspect the assemblies. Quality welds are highly dependent upon achieving appropriate temperatures everywhere along the bond line. The present invention is a system that uses a secondary coil to detect misalignment between the induction coil and the susceptor which would result in an excessive bond line temperature (in portions of the weld) and to provide control signals for the coil or parasitic compensation to avoid the overheating.

Abstract: An induction heating apparatus having a refractory vessel for holding a quantity of material to be heated by the apparatus. The vessel being surrounded by, but does not touch, an induction coil having a plurality of helical turns. The turns of the induction coil have a surface on which is disposed a layer of high temperature superconducting material.

Abstract: A method for heating a fluid in a pipe by transforming induced current flowing through a conductor directly to heat energy as the conductor moves through a magnetic field. The method comprises locating N and S poles of a magnet adjacent the outer peripheral surface of a pipe on opposite sides, respectively thereof. A conductor in the form of heating wires is secured to a central shaft in the interior of the pipe. The heating wires have portions orthogonally intersecting with a magnetic line of force defined between the N and S poles and constitute a closed circuit. An impeller secured to the central shaft is caused to be rotated by the flow of the fluid flowing through the pipe, which in turn causes simultaneous rotation of the heating lines fixed to the central shaft. As a result the heating lines are heated due to induced current generated therein. This, in turn, heats the fluid.

Abstract: A die for use in an induction heating workcell incorporates segments of the induction coil in spaced array within a cast ceramic or phenolic body. A peripheral compression frame, typically of phenolic, surrounds the die body and applies a compressive load to the body through lateral and transverse reinforcing rods that are cast into the body. Matched dies close to trap heat in a workpiece at the center of the induction coil.

Abstract: An induction heater for heating a portion of a load comprises a side entry coil driven by a source of alternating current, with a flux concentrator located at the coil opening. The coil produces a magnetic field in the region occupied by the flux concentrator and the heated portion of the load. The flux concentrator extends along the opening of the coil and is fabricated of high permeability, low loss material, such as nickel-zinc ferrite, so as to enhance the uniformity of the magnetic field generated within the coil. In the preferred application, heating produces a complete fluid block in a cable section within the coil without overheating or damaging the cable.

Abstract: An induction furnace for homogeneously heating flat steel products fed therethrough in a continuous line in a predetermined feeding direction includes a succession of heating assemblies and pairs of rollers placed between the heating assemblies for supporting and moving the flat products in the feeding direction. Each heating assembly has a narrow induction coil fed by a separate frequency converter and a linear flux concentrator. The coil extends transverse to the feeding direction. The size of the coil in the feeding direction of the flat products is 350 mm. or less. The flux concentrator is in proximity of the coil and extends along the longitudinal orientation of the coil. The flux concentrator has ends, an upper portion and a lower portion. The upper and lower portions are joined at each of the ends, and establish a central gap therebetween for the flat products to pass therethrough. The gap extends through the heating assembly in a direction transverse to the longitudinal orientation of the coil.

Abstract: An induction heating coil assembly for use in a roller induction heating line has a magnetic shunt for receiving a portion of an electromagnetic field generated along the axis of the induction coil and directing that portion along a path parallel to a workpiece passing along the heating line. This flux path ensures that eddy currents induced in the workpiece flow primarily perpendicular to the axis of the workpiece, and not along the axis of the workpiece where they could cause arcing between the moving workpiece and the conveyor rolls.

Abstract: Apparatus for inductively heating metal can lids operates at medium frequency, with a many-turn induction coil wrapped partly or entirely around the can closures. No focusing cores are required, nor need the conductors be water cooled. Can ends may be fed through the apparatus in-stick. IGBTs are used in the H-bridge of the inverter. A control system is also provided which minimizes peak current flow through the switches and obviates the need for a series inductor conventionally used for current limiting. The control system monitors the tank voltage phase angle and turns the switches on and off in optimal response thereto. Can lids are separated magnetically while being motivated by sequentially switched electromagnets, and can bodies may be rotated by a split conveyor belt while being transported through inductive heating apparatus.

Abstract: An induction heating coil apparatus for heating continuous strip material comprising at least a pair of generally rectangular full-turn coils arranged in parallel relation and separated from each other to permit continuous strip material to pass axially through the open interiors of the coils. Each coil has an opening in a first end portion thereof such that continuous strip material may pass into or out of the interior of the coil apparatus. The coil apparatus further comprises a pair of shunt conductors connecting the respective coils to each other. The shunt conductors are arranged on opposite sides of the openings in the end portions of the coils for providing a continuous current path from one rectangular coil to the adjacent coil. In one preferred embodiment there is an opening in the second end portion of one coil. Two more conductors, one on each side of this opening, provide connection to the respective poles of an alternating current power source.

Abstract: Induction heating is utilized to heat polymer matrix composites containing electrically conductive fibers. This is accomplished with an apparatus having a mold with first and second cores positioned to receive a workpiece therebetween and first and second induction coils mounted to the first and second cores, respectively. Each induction coil is encapsulated in a layer of non-electrically conductive material which is attached to a surface of the respective core. A thermal insulation layer is attached to each layer of material, and a skin layer is attached to each thermal insulation layer. Alternatively, the induction coils can be embedded in the corresponding mold core. In another alternative, a single helical induction coil can be disposed around the two mold cores.

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: Device for the inductive flow-heating of an electrically conductive pumpable medium, whereby there are provided in the device pipeline windings, through which the medium flows, on a magnetic yoke in which with the aid of an inductive alternating current energy transfer in accordance with the transformer principle electric voltages are induced. At least two such pipeline windings are connected with each other via supply distributor and mixer pieces in such a way that a short-circuit current flows in a closed path of the medium in the pipeline windings, fed by the induced voltages, which heats the medium. A further development provides that there are provided heating elements connected with the pipeline windings and adapted in dimensions to these windings, in which heating elements a rapid local heating can be obtained through current density concentration.

Abstract: An inductive cooker heating system has a high frequency-supplied induction coil. The thickness or wire thickness of the single conductors for a conventional frequency between 20 and 30 kHz (25 kHz), is approximately 0.2 mm. This limited wire thickness has proved to be particularly low-loss. The arrangement of the induction cooking point comprises a thermal insulation placed below a plate for receiving cooking vessels, a shield with branched, grounded line structures and a disk-like induction coil, which is back-connected on the underside by a ferrite yoke plate.

Abstract: Electromagnetic-induction heating coil, especially for the heating of metallurgical products, in which coil conductors are cooled with the aid of a tube in which a cooling fluid, in thermal contact with the conductors, circulates, wherein the conductors are wound in at least one ply, as a helix around the cooling tube so that the ply has at least one twist of one complete turn between two electrical terminals of the coil.

Abstract: A method of case hardening a steering gear rack bar having a plain cylindrical barrel portion and an integral toothed portion on which are formed a plurality of rack gear teeth each having a predetermined helix angle relative to a longitudinal centerline of the rack bar. The method includes forming an induction coil having a linear section and a spiral section with a helix angle equal to the helix angle of the rack gear teeth, locating the rack bar inside the induction coil with the barrel portion thereof juxtaposed the linear section of the induction coil and with the spiral section of the induction coil surrounding the toothed portion, rotating the rack bar about its longitudinal centerline while passing alternating electric current through the coil to concurrently induction heat both the barrel portion and the toothed portion, and quenching the rack bar after the alternating current is turned off.

Abstract: The product (11) is in relative motion in the direction (12) of its axis with respect to at least one magnetic inductor (10, 10'). The metallurgical product (11) is subjected to at least two magnetic fluxes (19, 19') having non-parallel directions which are transverse with respect to the longitudinal direction of the product (11). The heating device may advantageously consist of two C-shaped magnetic yokes (14, 14') spaced apart and angularly offset along the axial direction (12) of advance of the product (11).

Abstract: For heating at a constant temperature, an inductive heating element such as a heating plate includes a magnetic material and a thermistor material, e.g., in layered form or in the form of particles. The thermistor material may be a PTC or a NTC thermistor material. A mixture of PTC thermistor, NTC thermistor, and magnetic particles may be used, e.g., in a proportion for minimized bulk resistance.

Abstract: An improved transformer (10) for heating a selected filament during a stretching procedure to enhance the quality and tensile strength of the filament. The transformer (10) is fabricated around a spool body (12) which is mounted on a motor and received within a rotating shield. As power is supplied to the transformer (10), heat is generated, a portion of this heat being transferred to the rotating shield and finally to the selected filament. A base layer of insulation (14) is applied to an exterior surface of the spool body (12), including the flanges (32,38), for preventing generated heat from damaging the spool (12) and also to prevent an inductor wire (18) from shorting on the spool (12). The inductor wire (18) is wrapped from one end of the spool body (12) to the other. During the wrapping of the inductor wire (18), an insulating material (20) is sprayed on to fill any voids between the wire (18) and the spool (12), and between the individual turns of the inductor wire (18).

Abstract: An induction-hardening machine for the contour hardening of cross-axis, intersecting-axis and nonintersecting-axis gears such as hypoid gears includes a programmable logic control unit, a source of quench liquid and a high-frequency induction generator which are operably connected to a high-frequency induction coil which, in one embodiment, is disposed at an inclined angle above the horizontally disposed workpiece (hypoid gear). Fluid connections are made between the source of quench liquid and the induction coil for the rapid delivery of quench liquid. The support platform for the hypoid gear is connected to a rotary drive motor and with the hypoid gear rotating at approximately 900 to 1800 RPM the induction coil is energized with four low energy pulses of relatively short duration. The final heating step is a high energy pulse followed immediately by the quenching step.

Abstract: The invention relates to an inductor having two parallel main heating conductors which are interconnected at one of their ends via a bridge-shaped branch and are connected at their other end to a transformer, the connections also forming a bridge-shaped conductor branch. The characterizing feature of the invention is that disposed at least at one end of the parallel main heating conductors is a separate auxiliary inductor which is mounted displaceably in relation thereto and has two conductor portions parallel with the main heating conductors and inductively coupled thereto which are collectively interconnected at one of their axial ends via a bridge-shaped conductor branch determining the end of the heating zone and at the other end via a tunnel-shaped return conductor which over the whole displacement length is disposed beneath the bridge-shaped branch of the main heating conductors and is inductively coupled thereto.

Abstract: A device for inductively heating flat metal objects, with at least one pair of induction coils which form a gap through which the object is moved. The induction coils have an iron core made up of transformer stampings with grooves in which current conductors are arranged. The iron cores of at least one inductor coil have grooves which run in a zig-zag or undulating fashion along the direction of motion of the object being heated. The maximum angle the grooves make with the direction of movement of the object is 60.degree., and the current conductors are disposed in the grooves so as to follow the zig-zags or undulations thereof. The inductor coils of at least one inductor-coil pair include several side-by-side conductors which are arranged so as to carry current in the same direction along the coil. At least some of the current conductors are arranged for selective independent electrical connection to a source of electrical energy.

Abstract: An induction heating apparatus has a coil or coils which can be opened without using electrical contacts. One continuous electric current passageway is formed by a first coil section, a second coil section, a first connecting conductor and a second connecting conductor. By feeding electric power to this electric current passageway and passing an object through a space at the central portion of the coil sections, the object is induction heated. A gap is provided between the first connecting conductor and the second connecting conductor, or the respective connecting conductors can be opened and closed relative to one another to vary the size of the space therebetween. The object to be heated is carried into the space at the central portion of the coil and is carried out therefrom through the gap or the space between the conductors.

Abstract: This disclosure relates to an apparatus for and a method of electrical inductance heating of metal strips and slabs. The heating method involves a plurality of pairs of individual electrical coils exposed on opposite sides of a path of movement of a metal strip or slab wherein the coils are elongated longitudinally of the path of movement of the metal member, such as a strip or slab, whereby the pattern of heating is in the way of stripes. Further, to eliminate any pulsing of current within the strip or slab being heated, each coil is spaced from a transversely adjacent coil a distance corresponding substantially to the effective heating width of that coil. The coils of a next longitudinal adjacent set of coils are transversely offset relative to the coils of the first mentioned set of coils so that each coil of the second set is aligned with a space between coils of the first set. This provides for a heating of the strip or slab in stripes and prevents overheating of the edges of the strip or slab.

Abstract: A contact lens treating vessel equipped with an electromagnetic induction coil and a rectifier for converting an alternating current into a direct current, and an apparatus for treating contact lenses comprising a treating apparatus body for supplying electric power and the vessel which can be attached to or detached from the apparatus body, wherein the apparatus body is equipped with a magnet-generating coil and the vessel is equipped with an electromagnetic induction coil.

Abstract: A temperature-measuring device for an induction-type cooking appliance is disclosed with a heat measuring device for an induction-type cooking hob including a heat conductor for measuring the temperature of a sauce pan or its contents independently of its diameter or its bottom surface configuration. A heat conductor includes modifications which minimize the effects of currents provided by the induction heating. The device allows for the measurement of temperature during induction heating.

Abstract: A superconducting magnet coil is protected from local damage due to quenching by inductively driven heaters formed by heater strips embedded in the coil and connected in closed loops. A cold bypass diode shunting the coil winding commutates current out of the magnet when the voltage drop across the region of the coil which has gone normal exceeds the forward bias of the diode. This change in coil current induces sufficient current in the heater loops to cause the entire coil to go normal for uniform dissipation of stored energy throughout the magnet.