Induction heating, temperature self-regulating
First Claim
1. Food temperature control apparatus comprising:
- a food-holding container including a ferromagnetic induction heating element having a Curie temperature;
a magnetic induction heater including a magnetic field generator for generating a magnetic field, said heater including a resonant circuit having an induction coil;
said heater operable to heat said element when the element is magnetically coupled with said magnetic field; and
a temperature controller for controlling the temperature of said element about a regulation temperature at or above said Curie temperature during the course of heating of the element above ambient, said controller including a sensor operable for measuring a circuit parameter related to the amplitude of the resonant current passing through the resonant circuit while magnetically coupled with said element and a microprocessor operable for calculating the change of said circuit parameter over a chosen time period, said controller operable to alter the field strength of said magnetic field when at least one of said circuit parameter and its rate of change is above or below a respective selected value and only after said rate of change has first exceeded a predetermined value which insures that the temperature of the element is nearing said regulation temperature, said selected value correlated with said regulation temperature, said heating element being adjacent an insulating member, said member located within said container.
6 Assignments
0 Petitions
Accused Products
Abstract
Temperature self-regulating food delivery systems are provided having a magnetic induction heater (32, 126) and an associated food container (76, 124) equipped with an essentially permanent ferromagnetic heating element (82, 100, 128). The heater (32, 126) and heating elements (82, 100, 128) are designed so as to heat the element (82, 100, 128) to a user-selected regulation temperature when the elements (82, 100, 128) are coupled with the heater'"'"'s magnetic field, and to maintain the temperature in the vicinity of the regulation temperature indefinitely temperature regulation is a heating achieved by periodically determining at least two parameters of the heaters resonant circuits related to the amplitude of the resonant current passing therethrough during heating and responsively altering the field strength of the magnetic field. Preferably, the value of the resonant circuit amplitude and the rate of change of the amplitude are determine.
118 Citations
32 Claims
-
1. Food temperature control apparatus comprising:
-
a food-holding container including a ferromagnetic induction heating element having a Curie temperature;
a magnetic induction heater including a magnetic field generator for generating a magnetic field, said heater including a resonant circuit having an induction coil;
said heater operable to heat said element when the element is magnetically coupled with said magnetic field; and
a temperature controller for controlling the temperature of said element about a regulation temperature at or above said Curie temperature during the course of heating of the element above ambient, said controller including a sensor operable for measuring a circuit parameter related to the amplitude of the resonant current passing through the resonant circuit while magnetically coupled with said element and a microprocessor operable for calculating the change of said circuit parameter over a chosen time period, said controller operable to alter the field strength of said magnetic field when at least one of said circuit parameter and its rate of change is above or below a respective selected value and only after said rate of change has first exceeded a predetermined value which insures that the temperature of the element is nearing said regulation temperature, said selected value correlated with said regulation temperature, said heating element being adjacent an insulating member, said member located within said container. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. Food temperature control apparatus comprising:
-
a food-holding container including a ferromagnetic induction heating element having a Curie temperature and an outer wall;
a magnetic induction heater including a magnetic field generator for generating a magnetic field, said heater including a resonant circuit having an induction coil;
said heater operable to heat said element when the element is magnetically coupled with said magnetic field; and
a temperature controller for controlling the temperature of said element about a regulation temperature at or above said Curie temperature during the course of heating of the element above ambient, said controller including a sensor operable for measuring a circuit parameter related to the amplitude of the resonant current passing through the resonant circuit while magnetically coupled with said element and a microprocessor operable for calculating the change of said circuit parameter over a chosen time period, said controller operable to alter the field strength of said magnetic field when at least one of said circuit parameter and its rate of change is above or below a respective selected value and only after said rate of change has first exceeded a predetermined value which insures that the temperature of the element is nearing said regulation temperature, said selected value correlated with said regulation temperature, there being a member between said heating element and the outer wall of the food-holding container whose position relative to the heating element is fixed, said member and element being located within said container. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
-
-
17. Food temperature control apparatus comprising:
-
a food-holding container including a ferromagnetic heating clement;
a magnetic induction heater including a magnetic field generator for generating a magnetic field, said heater including a resonant circuit having an induction coil;
said heater operable to heat said element when the element is magnetically coupled with said magnetic field; and
a temperature controller for controlling the temperature of said element about a regulation temperature of the element during the course of heating of the element above ambient, said controller including a sensor operable for measuring a circuit parameter related to the amplitude of the resonant current passing through the resonant circuit while magnetically coupled with said element and a microprocessor operable for calculating the change of said circuit parameter over a chosen time period, said controller operable to alter the magnetic field strength of said magnetic field when at least one of said circuit parameter and its rate of change is above or below a respective selected value, said value correlated with said regulation temperature said heating element adjacent an insulating member, said member located within said container. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
-
-
25. Food temperature control apparatus comprising:
-
a food-holding container including a ferromagnetic heating element and an outer wall;
a magnetic induction heater including a magnetic field generator for generating a magnetic field, said heater including a resonant circuit having an induction coil;
said heater operable to heat said element when the element is magnetically coupled with said magnetic field; and
a temperature controller for controlling the temperature of said element about a regulation temperature of the element during the course of heating of the element above ambient, said controller including a sensor operable for measuring a circuit parameter related to the amplitude of the resonant current passing through the resonant circuit while magnetically coupled with said element and a microprocessor operable for calculating the change of said circuit parameter over a chosen time period, said controller operable to alter the magnetic field strength of said magnetic field when at least one of said circuit parameter and its rate of change is above or below a respective selected value, said value correlated with said regulation temperature, there being a member between said heating element and that outer wall of the food-holding container whose position relative to the heating element is fixed, said member and element being located within said container. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32)
-
Specification