Abstract: A diathermal water heater for the rapid and controlled heating of water and like fluids. A diathermal heating chamber uses electrical oscillations to heat liquids flowing through it. By means of feedback circuitry, the electrical oscillations are controlled to provide liquids at a constant temperature. Household and industrial quantities of hot water, wet steam and dry steam may be generated by the water heater. The heater itself is compact and can be used to provide one pipe plumbing to provide water at controlled heated temperatures.

Abstract: An inductive hot point heating system is regulated or controlled by an oscillation packet control, which uses a symmetrical pattern of complete mains half-waves. The switching takes place in the zero passage and is symmetrical in such a way that there is no d.c. voltage component in the mains. It also contains an optical temperature monitoring of the plate covering the cooking point with an infrared photosensor, which determines the temperature on the basis of its predetermined spectral range.

Abstract: A resonance circuit including a high frequency induction heating coil is set to a resonance state and a heating temperature of an object to be heated (for example, catalytic converter or the like) is controlled on the basis of a resonance frequency varied with an increased temperature of the object under the resonance state.

Abstract: An electromagnetic induction heating cooker includes a heating coil situated below a cooking plate and mounted on a mounting plate. An attachment assembly is connected to the mounting plate within the center of the coil. The attachment assembly includes a pair of horizontally projecting pieces which overlie the coil and press downwardly thereagainst. A temperature sensor carried by the holder is spring-biased upwardly into contact with the underside of the cooking plate. The holder carries a thermal fuse for shutting off the coil when a sensed temperature exceeds a reference temperature.

Abstract: A fiber optic cable extends into the housing of an induction heater and has a sensing end positioned to confront a part being heated. Infrared radiation from the part is transmitted by the cable to a transducer. The transducer converts the infrared energy into an electrical signal that is used by a control circuit to control the heating operation. The control circuit has an internal electronic timer that is used in normal operation and to detect certain failure conditions. In normal operation, electromagnetic pulses are provided to the heater at a predetermined power level until the part reaches a predetermined temperature. Then the control circuit adjusts the power level to hold the part at the temperature for a brief holding period. The timer is used by the control circuit to detect failure to reach a desired temperature after a maximum delay and to detect dropping of the temperature below a minimum level during the holding period. The control circuit also detects overheating of the workpiece.

Abstract: An overheat prevention circuit for an electromagnetic induction heating cooker. The electromagnetic induction heating cooker has a heating coil, a top plate disposed over the heating coil, on which an object to be heated is laid, a temperature sensing part for sensing a temperature of the object and a high-frequency power generation part for generating a high-frequency magnetic field to the heating coil to induction-heat the object.

Abstract: The present invention generally relates to a high frequency soldering iron. In particular, the soldering iron of the present invention is provided with a tip which is directly heated for a quick heating to a desirable temperature set by a temperature setting means. The soldering iron is also provided with a sensor for detecting the temperature of the soldering iron tip. A temperature comparator compares the sensed tip temperature against the set soldering temperature to maintain the tip temperature constant at the set temperature.

Abstract: An apparatus for the inductive cross-field heating of flat material includes a plurality of mutually opposite induction loops being disposed above and below the flat material. At least one pair of induction modules is formed of two induction modules being adjustable independently of one another in their position relative to the flat material. Each induction module has two mutually opposite U-shaped induction loops having geometries and dimensions which are invariable, base legs which can be positioned in such a way that they terminate at least a predeterminable distance in front of one edge of the flat material and within the width of the flat material, and two side legs which can be positioned in such a way that they project at least a predeterminable distance beyond the other edge of the flat material.

Abstract: An apparatus is disclosed for performing thermomechanical processing of gears in which precise control of the thermal, metallurgical and mechanical action during the forming process is maintained. The apparatus comprises an induction heating system which reaustenitizes the surface of the gear with minimum decarburization, a material transfer system which provides timely operations on the work piece, tooling and fixture adjustments which provide accurate initial conditions for forming, and a process control architecture that provides the precise sequence and timing necessary to achieve metallurgically sound and dimensionally accurate gears. Using this invention the induction heating cycle can be controlled from the peak, average or minimum gear surface temperature detected with a high response optical pyrometer. An inert environment is maintained around the workpiece during the induction heating and transfer to quenching above the M.sub.s temperature.

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 electromagnetic induction steam generator is compact or ultra-compact and highly efficient, and capable of continuous operation, intermittent operation and empty-heating operation. Magnetic flux passes through a closed magnetic circuit of two leg iron cores, a heater, and a yoke iron core after a low-frequency alternating current is supplied from a power supply to electric wire coils. Joule heat is generated inside the heater by the permeation of magnetic flux. When fluid such as water, is supplied from the fluid supply port, it is heated and becomes steam within the heating chamber. The steam then emerges from the steam output port.

Abstract: Induction heating apparatus, typically for metal melting, with multiple zone temperature control has an induction coil (10) divided into individual sections (10a, b, c) associated with respective zones and powered in parallel under regulation from controller (20) as shown in FIG. 1. To give precise and efficient automatic regulation of the zone temperatures the power supply is provided by a resonant invertor (14) as a medium frequency pulsed output and at an instantaneously selected level which is the sum of the power requirements of all the zones at any instant, and the average power applied in each zone is controlled by pulse width modulation with switching to high power for a proportion, determined by demand in that zone, of each of successive standard time periods.

Abstract: A high frequency cooker which detects a sound generated upon boiling of a material to be heated in response to the material being heated and switch as to a cooking mode in response to the detected signal of that sound. The cooker comprises a heating section for heating a material to be heated, a sensor for detecting a sound generated from the material to be heated upon boiling of the material to be heated, and a control section for controlling the heating section in response to the detected sound. The cooker can sense the sound of the material to be heated and can switch automatically from a cooking mode to a warm mode even by only making a single function selection. An optimum cooking state of the food can be maintained, and unnecessary power loss can also be prevented.

Abstract: In the fluid heater disclosed herein, a plurality of thin or ribbon-like conductors are embedded in and link a pair of similar flow paths. An inductor is magnetically coupled to the conductors and is energized with alternating current thereby to induce local currents in the conductors and generate heat which is imparted to fluid passing through the flow paths and over the surfaces of the conductors.