Abstract: Induction heating apparatus has a series inductor between an AC source and a parallel tank circuit.

Abstract: An induction furnace having a voltage source series inverter, a load circuit having a combination of an induction coil and a resonating capacitor bank, and control circuitry to phase lock the inverter frequency to the natural resonant frequency of the load. The capacitor bank can be divided into two groups, one across the output of the inverter and the other in series with the load. This arrangement allows for the division of the inverter voltage across the furnace coil according to the ratio of the two capacitances. The inverter uses pulse width modulation and is buffered from the load circuit by means of a small series connected inductor. Additionally, the system can have a common power supply system that supplies power in any desired proportion to a plurality of induction furnaces.

Abstract: A robot body has an articulated manipulator arm having a welding tool. The robot body is installed on a base stand housing electric circuits including a welding power source. The electric circuits provide for driving and controlling the welding tool. The robot thus provided minimizes the space needed for installation thereof and requires less time for installation and fewer parts, whereby it becomes possible to reduce the manufacturing cost, simplify the robot installation operation and obtain a stable welding performance.

Abstract: A drink can induction heating apparatus includes a ferrite core having a plurality of projected portions and recesses formed between the adjacent projected portions. When a drink can is set in a position to be heated, each of the projected portions is oriented toward a longitudinal axis of the drink can and a particular portion of a circumferential wall of the drink can. The apparatus further includes a saddle-shaped heating coil which is partly received in the recesses of the ferrite core and covers a region around the foregoing particular portions of the drink can in a non-contact manner, and an inverter for feeding the AC power to the heating coil. The inverter is arranged to produce the AC power at a resonance frequency which corresponds to one of 5 kHz to 15 kHz where equivalent resistance values of an aluminum can and a steel can approximate to each other.

Abstract: A method for the in-situ vitrification of waste materials in a disposable can that includes an inner container and an outer container is disclosed. The method includes the steps of adding frit and waste materials to the inner container, removing any excess water, heating the inner container such that the frit and waste materials melt and vitrify after cooling, while maintaining the outer container at a significantly lower temperature than the inner container. The disposable can is then cooled to ambient temperatures and stored. A device for the in-situ vitrification of waste material in a disposable can is also disclosed.

Abstract: An apparatus for heating a metal surface to remove a nonferrous thermosetting resin coating bonded to the metal surface. The apparatus uses a power supply device for providing an approximately 75-100 kW signal at approximately 10-40 kHz to the apparatus. A coil assembly device is coupled to the power supply device for producing a high frequency inductive field which will penetrate through the nonferrous thermosetting resin coating with virtually no attenuation and will induce an eddy current of sufficient power in the underlying metal substrate to rapidly heat the interface to a sufficient temperature to immediately destroy the interface bond between the nonferrous thermosetting coating and the metal substrate.

Abstract: An induction cooker comprises at least one cooking heater comprising an inductor, a generator delivering a AC current to supply the inductor and an element made of a non-magnetic, electrically conductive material to provide shielding against the disturbances generated by the inductor. The shielding function is improved by electrically connecting the element to the mains by means of a high-frequency filter of the generator. Preferably, the electrical link between the shielding and the filter comprises a capacitor.

Abstract: A method and apparatus are provided for heating a solid material and dispensing the material as a liquid. A central housing has an inlet, a dispensing orifice and a flow passage extending through the central housing for passing the material from the inlet to the dispensing orifice. A susceptor and induction coil are disposed within the flow passage for immersion within the material after it is liquified. The susceptor includes a conically shaped flow section which extends across the flow passage, and a plurality of flow ports for passing the material. The susceptor further includes a cylindrical section which extends downstream from the flow section for receiving the material from the flow section and passing material to the dispensing orifice. The induction coil is aligned with and spaced downstream from the flow section of the susceptor, surrounding part of the susceptor for electromagnetically inducing electric currents to flow within the flow section.

Abstract: Radio frequency power for melting, sealing and welding plastic tubing compressed between a pair of manually or automatically actuated electrically conducting jaws of a hand held or fixed base tubing sealer is regulated by a pulse width modulator controlling the duty cycle of applied constant voltage pulses. A predetermined change of impedance of the tubing during compression and melting is detected to regulate the power applied and to ensure a weld of predetermined physical parameters. On completion of the weld, a first timer is reset and a further weld may be made. In the event of impedance mismatch, a second timer inhibits further application of power and resetting of the first timer. The use of the pulse width modulator enhances conservation of power and accommodates portability of the tubing sealer through use of rechargeable batteries as the power source.

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: This invention relates to heat-recoverable devices that are self-heating and auto-regulating. The heat-recoverable articles of this invention comprise the combination of a heat-recoverable material and lossy heating particles, such as ferromanetic or ferrimagnetic particles, which produce heat when subjected to an alternating magnetic field and have a Curie temperature at or above the recovery temperature of the material and preferably below the decomposition temperature of the material. The particles can be in an electrically non-conductive layer, on or in thermal contact with the heat-recoverable material or can be dispersed in the heat-recoverable material. The system of this invention includes the heat-recoverable device or article, an induction coil for producing the magnetic field and an alternating current power supply for the induction coil. Preferably the power supply is high frequency and constant current, which produces efficient heating and preferred auto-regulating properties.

Abstract: A tray transport cart which accommodates trays for holding dishes for containing meals has a movable cart body with a plurality of tray carriers installed therein. Induction coils are inserted into the tray carriers for generating a local electromagnetic field. The trays hold the dishes which are provided with a current-conducting layer. An HF generator positioned on the cart body cooperates with the induction coils to produce the total inductance of the coils to generate a desired induction current in the current-conducting layer of the dishes, in the range between 32 .mu.H and 76 .mu.H, to maintain the meals contained in the dishes at warm temperatures.

Abstract: In a system of supplying electric power to an induction furnace, a required heating power is directly supplied to the induction furnace from an ac synchronous generator driven by a prime mover, such as a diesel engine, via a single-phase coil. At the same time, the voltage to be supplied to the single-phase coil is rendered continuously variable by an automatic voltage regulator of the generator to render continuously variable the heating power corresponding to the voltage to be supplied, and the frequency of the voltage to be supplied is rendered continuously variable by an automatic frequency regulator of the prime mover in accordance with predetermined mutual relationships with the voltage to be supplied. In addition, at the start of power supply, the voltage to be supplied and the frequency thereof are increased with gradients for a predetermined time duration from their predetermined minimum values to their rated values in accordance with the predetermined mutual relationships.

Abstract: A heater system provides a portable lightweight tool including the core and at least the primary winding of a transformer having a secondary that may be permanently or selectively coupled to a heater having a bifilar winding to reduce magnetic radiation; wherein the design of the system is such that voltages produced in the portable tool do not materially exceed 100 volts and are normally below 100 volts. The core of the transformer when employed in an arrangement wherein the secondary winding is permanently connected to the heater winding has a leg rotatable out of the closed core configuration whereby another leg of the core having the primary winding wound thereon may be inserted into the secondary winding. Alternatively the secondary winding may be wound on a short length of the core that is insertable into a leg of the transformer core on which the primary winding is wound.

Abstract: Radio frequency power for melting, sealing and welding plastic tubing compressed between a pair of manually or automatically actuated electrically conducting jaws of a hand held or fixed base tubing sealer is regulated by a pulse width modulator controlling the duty cycle of applied constant voltage pulses. A predetermined change of impedance of the tubing during compression and melting is detected to regulate the power applied and to ensure a weld of predetermined physical parameters. On completion of the weld, a first timer is reset and a further weld may be made. In the event of impedance mismatch, a second timer inhibits further application of power and resetting of the first timer. The use of the pulse width modulator enhances conservation of power and accommodates portability of the tubing sealer through use of rechargeable batteries as the power source.

Abstract: A dual push-pull induction heating drive circuit comprises an oscillation triggering control circuit regulating the ON-OFF switch of the circuit activation, a switching logic circuit bringing about two exclusive pulse signals serving to drive via an amplifying circuit a dual push-pull switching output circuit having two power elements connected to an induction coil, a pulse width modulating circuit having a controlled comparing element capable of sending out adjustable pulse, and a synchronous detection comparing circuit having at least a comparing element and having an input end in communication with an induction coil and another input end connected with a power source and further having an output end connecting with the switching logic circuit and sending out synchronous pulse signals to a differentiation circuit to bring about synchronous differentiation pulse signals, which are received by the pulse width modulating circuit so as to generate the power control pulse signals serving via the switching logic

Abstract: A Curie point heater primarily for use in a soldering iron and initially designed to operate with currents in the megahertz range is restructured to operate in the kilohertz range. Further in one embodiment of the heater, the coil exciting the heater is mounted in the handle of the iron.

Abstract: This invention relates to heat-recoverable devices that are self-heating and auto-regulating. The heat-recoverable articles of this invention comprise the combination of a heat-recoverable material and lossy heating particles, such as ferromanetic or ferrimagnetic particles, which produce heat when subjected to an alternating magnetic field and have a Curie temperature at or above the recovery temperature of the material and preferably below the decomposition temperature of the material. The particles can be in an electrically non-conductive layer, on or in thermal contact with the heat-recoverable material or can be dispersed in the heat-recoverable material. The system of this invention includes the heat-recoverable device or article, an induction coil for producing the magnetic field and an alternating current power supply for the induction coil. Preferably the power supply is high frequency and constant current, which produces efficient heating and preferred auto-regulating properties.

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.