Induction cooking appliance including temperature sensing of food in inductively heated vessel with immersion-type temperature sensing means

Claim 2

An induction cooking appliance, for heating a vessel having at least one portion in which heating current may be induced to heat said one portion whereby said one portion may heat food contained by said vessel, comprising: vessel supporting means in which no substantial heating current is induced when said vessel supporting means is subjected to a changing magnetic field; an induction coil energizable for generating a changing magnetic field in said one portion of said vessel to heat said vessel when said vessel is Supported by said vessel supporting means; means for energizing said induction coil with electric power of at least ultrasonic frequency; temperature sensing means adapted to make contact with food in the vessel, said temperature sensing means providing a change in electrical impedance corresponding to a change in the temperature of the food in the vessel; conductor means connected with said temperature sensing means and extending therefrom to a location outside the vessel; magnetic coupling means connected to said conductor means and adapted for being supported by said vessel supporting means at a location outside said vessel; magnetic receptor means supported by said vessel supporting means and magnetically coupled with said magnetic coupling means supported by said vessel supporting means whereby changes in the impedance of said temperature sensing means are reflected to said magnetic receptor means through said magnetic coupling means; and, temperature signal processing circuitry coupled with said magnetic receptor means for providing a signal representative of the temperature of the food in the vessel corresponding to the temperature-correlated impedance of said temperature sensing means.

Claim 3

The induction cooking appliance according to claim 1 wherein said temperature sensing means is comprised of a thermistor unit.

Claim 4

The induction cooking appliance according to claim 1 wherein said conductor means is comprised of a flexible cable.

Claim 5

The induction cooking appliance according to claim 1 wherein said vessel supporting means includes an uninterrupted surface on which said vessel is supportable.

Claim 6

The induction cooking appliance according to claim 1 wherein said vessel supporting means includes an uninterrupted surface on which said vessel and said magnetic coupling means are supportable.

Claim 7

An induction cooking appliance according to claim 5 wherein said magnetic coupling means is portable and manually positionable on said surface so as to be coupled magnetically with said magnetic receptor means.

Claim 8

The induction cooking appliance according to claim 6 wherein said magnetic coupling means and said magnetic receptor means each include separate permanent magnet means and wherein said vessel supporting means includes another surface opposite said uninterrupted surface and separated therefrom by said supporting means, said magnetic receptor means being supported on said other surface, said permanent magnet means of the respective coupling and receptor means enabling said positionable coupling means and receptor means to be latched by magnetic force in a magnetically coupled relationship on the opposite surfaces of said vessel supporting means.

Claim 9

The induction cooking appliance according to claim 7 wherein said magnetic coupling means and said magnetic receptor means each include a magnetic core and a coil magnetically coupled with said core, said separate permanent magnet means providing, in addition, a magnetic shield for the cores and coils of the respective coupling and receptor means, said coil of said coupling means being connected with said conductor means and said coil of said receptor means being connected with said temperature signal processing circuitry.

Claim 10

The induction cooking appliance according to claim 8 wherein said temperature signal processing circuitry drives the coil of said receptor means with electrical energy having a frequency different from the frequency of the electrical energy which drives said induction coil.

Claim 11

An induction cooking range, for heating a vessel in which heating current may be induced to heat the vessel and food contained therein, comprising: a counter in which no substantial heating current is induced when the counter is in a changing magnetic field, said counter including first and second surfaces on opposite sides thereof; an induction coil energizable for generating a changing magnetic field in said vessel to heat said vessel and the food therein when said vessel is rested on said first surface of sAid counter; means for energizing said induction coil with electric power of at least ultrasonic frequency; a thermistor probe unit adapted for contacting the food in said vessel, said thermistor probe unit having electrical resistance which varies as a function of the temperature of the food in said vessel; flexible conductor means connected to said thermistor probe unit and extending from the probe unit to a location outside the vessel; portable magnetic coupling means manually positionable on said first surface of said counter and including a magnetic core and a coil magnetically coupled with said core, said flexible conductor means being connected to said coil of said magnetic coupling means; magnetic receptor means supported on said second surface of said counter and including a magnetic core and a coil magnetically coupled with said core, said magnetic coupling means being manually positionable with respect to said magnetic receptor means such that the magnetic cores of said coupling and receptor means are magnetically coupled although separated by the intervening counter; and, temperature signal processing circuitry including conductor means connected to the coil of said receptor means, said temperature signal processing circuitry providing a signal representative of the temperature of the food in the vessel corresponding to the temperature-correlated electrical resistance of said probe unit as said electrical resistance is reflected to said temperature signal processing circuitry through the magnetically coupled coils of said coupling means and said receptor means.

Claim 12

An induction cooking range, for heating a vessel in which heating current may be induced to heat the vessel and food contained therein, comprising: a counter in which no substantial heating current is induced when the counter is in a changing magnetic field, said counter including first and second surfaces on opposite sides thereof; an induction coil energizable for generating a changing magnetic field in said vessel to heat said vessel and the food therein when said vessel is rested on said first surface of sAid counter; means for energizing said induction coil with electric power of at least ultrasonic frequency; a thermistor probe unit adapted for contacting the food in said vessel, said thermistor probe unit having electrical resistance which varies as a function of the temperature of the food in said vessel; flexible conductor means connected to said thermistor probe unit and extending from the probe unit to a location outside the vessel; portable magnetic coupling means manually positionable on said first surface of said counter and including a magnetic core and a coil magnetically coupled with said core, said flexible conductor means being connected to said coil of said magnetic coupling means; magnetic receptor means supported on said second surface of said counter and including a magnetic core and a coil magnetically coupled with said core, said magnetic coupling means being manually positionable with respect to said magnetic receptor means such that the magnetic cores of said coupling and receptor means are magnetically coupled although separated by the intervening counter; and, temperature signal processing circuitry including conductor means connected to the coil of said receptor means, said temperature signal processing circuitry providing a signal representative of the temperature of the food in the vessel corresponding to the temperature-correlated electrical resistance of said probe unit as said electrical resistance is reflected to said temperature signal processing circuitry through the magnetically coupled coils of said coupling means and said receptor means.

Claim 13

The induction cooking range according to claim 10 wherein said coupling means and said receptor means are further comprised of separate means for magnetically shielding the respective cores and coils of said coupling means and said receptor means.

Claim 14

A cooking appliance, for heating a food-containing vessel, comprising: non-metallic vessel supporting means; means for heating food in the vessel; temperature sensing means adapted to make contact with food in the vessel, said temperature sensing means providing a change in electrical impedance corresponding to a change in the temperature of the food in the vessel; electrical conductor means coupled with said temperature sensing means and extendable therefrom to a location outside the vessel; magnetic coupling means coupled with said conductor means and positionable at a location outside said vessel on said supporting means; magnetic receptor means adapted to be magnetically coupled with said magnetic coupling means at a location outside said vessel on said vessel supporting means whereby changes in the impedance of said temperature sensing means are electromagnetically translated to said receptor means; and, temperature signal processing circuitry coupled with said receptor means for supplying electrical energy to said receptor means and for providing a signal representative of temperature-correlated impedance of said temperature sensing means.

Claim 15

A cooking appliance, for heating a food-containing vessel, comprising: non-metallic vessel supporting means; means for heating food in the vessel; temperature sensing means adapted to make contact with food in the vessel, said temperature sensing means providing a change in electrical impedance corresponding to a change in the temperature of the food in the vessel; electrical conductor means coupled with said temperature sensing means and extendable therefrom to a location outside the vessel; magnetic coupling means coupled with said conductor means and positionable at a location outside said vessel on said supporting means; magnetic receptor means adapted to be magnetically coupled with said magnetic coupling means at a location outside said vessel on said vessel supporting means whereby changes in the impedance of said temperature sensing means are electromagnetically translated to said receptor means; and, temperature signal processing circuitry coupled with said receptor means for supplying electrical energy to said receptor means and for providing a signal representative of temperature-correlated impedance of said temperature sensing means.