Abstract: An induction heating device comprises a frequency converter that generates a high-frequency drive voltage from an intermediate circuit voltage generated at least temporarily as a function of an AC mains voltage, a resonant circuit having an induction heating coil, with the drive voltage applied to the resonant circuit, and a temperature detection device that determines a temperature of a cooking vessel base which is heated by means of the induction heating coil. An auxiliary voltage source generated the intermediate circuit voltage over predefined time periods at a constant level. The frequency converter generates the drive voltage over time periods such that the resonant circuit oscillates at a natural resonant frequency in a substantially de-attenuated manner, and the temperature detection device further measuring at least one oscillation parameter over the time periods, and to evaluate the at least one measured oscillation parameter in order to determine the temperature.

Abstract: A method for heating a cooking vessel utilizing an induction heating device is provided. According to various aspects, the induction heating device includes a resonant circuit with an induction heating coil. A specified amount of energy may be supplied to the cooking vessel with the induction heating device depending on a heating power level selected by a user and/or on a cooking vessel type selected by the user. A parameter value of the resonant circuit which is dependent on a temperature of the cooking vessel, in particular of the bottom of the cooking vessel, may be determined and stored. The parameter value may be regulated to a setpoint which is dependent on the stored parameter value.

Abstract: A method and apparatus for preparing foodstuffs cooked in a liquid in a cooking vessel is provided. According to various aspects, an induction heating device includes a resonant circuit with an induction heating coil. A parameter value of the resonant circuit may be determined, depending on a temperature of a bottom of the vessel. During a heating-up phase, a high-frequency rectangular voltage may be applied to the resonant circuit to supply heating power to the bottom of the vessel. A heating power setpoint may be periodically varied and may be set to a first value during a first interval of a period, and set to a second, smaller value during a remaining interval. A determination of a change in the parameter value within the period may be made, and an evaluation of the change in order to determine the boiling point of the liquid and end the heating-up phase.

Abstract: A method for heating a liquid in a cooking vessel is provided. According to various aspects, an induction heating device includes a resonant circuit having an induction heating coil. A parameter value of the resonant circuit may be determined, depending on a temperature of the cooking vessel. A radio-frequency square-wave voltage may be applied at a predefined heating power setpoint value to the resonant circuit to supply heating power to the cooking vessel. The time profile of the parameter value may be evaluated for determining the boiling point of the liquid. After the boiling point has been determined, the heating power setpoint value may be reduced by a predefined amount over a predefined time period after which a current parameter value may be determined and stored. The parameter value may be adjusted to a setpoint value which is dependent on the stored parameter value.

Abstract: An induction heating device comprises a frequency converter that generates a high-frequency drive voltage from an intermediate circuit voltage generated at least temporarily as a function of an AC mains voltage, a resonant circuit having an induction heating coil, with the drive voltage applied to the resonant circuit, and a temperature detection device that determines a temperature of a cooking vessel base which is heated by means of the induction heating coil. An auxiliary voltage source generated the intermediate circuit voltage over predefined time periods at a constant level. The frequency converter generates the drive voltage over time periods such that the resonant circuit oscillates at a natural resonant frequency in a substantially de-attenuated manner, and the temperature detection device further measuring at least one oscillation parameter over the time periods, and to evaluate the at least one measured oscillation parameter in order to determine the temperature.

Abstract: A laboratory centrifuge for producing suspensions, sediments and the like, and for carrying out washing and similar processes, in which a motor-driven vertical shaft is arranged in a housing, said shaft carrying a shaft head on which magazines or such are pivotably mounted for receiving sample containers. The shaft head can be driven in either of two opposing directions and has two brackets arranged symmetrically to the axis of rotation the outwards extending arms of said brackets carrying an axle on which the magazines are pivotably mounted with axial play. The width of the magazines is slighter than the distance between the two bracket arms, and a locking device is present between the bracket arms and the magazines, becoming effective when the magazine abuts the respective bracket arm.