Three dimensional induction rethermalizing stations and control systems
AssigneeThe Vollrath Company, L.L.C.
InventorsPeter Roever, Yang Wang, John Wojcik
Life of this patent
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Abstract
A rethermalizing station includes a well defined by a side wall, a food pan configured to be inserted into the well and to hold a food item, a first induction coil surrounding the side wall of the well, the first induction coil configured to warm the food item via inductive heating of the food pan, a first temperature sensor configured to detect a temperature of the food pan, and a control unit coupled to the first induction coil and the first temperature sensor, the control unit configured to control the first induction coil in response to the temperature of the food pan detected by the first temperature sensor such that temperature of the food pan is maintained at a targeted temperature.
Claims19
A method of operation of a rethermalizing station comprising a well, a plurality of food pans configured to be positioned in the well, an induction coil extending around a perimeter of the well, and a plurality of moveable bottom induction coils configured to be repositioned in the well for alignment with the plurality of food pans, the method comprising:
- detecting a first temperature of a food pan of the plurality of food pans;
- sensing a current through the induction coil;
- calculating an index number based on the current;
- determining whether the index number exceeds a threshold index number, wherein the threshold index number distinguishes first pans acceptable for use with the induction coil from second pans unacceptable for use with the induction coil;
- responsive to a determination that the index number does exceed the threshold index number, turning off the induction coil;
- responsive to a determination that the index number does not exceed the threshold index number, controlling the induction coil without using an on/off duty cycle by:
- comparing the first temperature of the food pan to an upper temperature limit defined as a function of a targeted temperature;
- and
- if the first temperature of the food pan is greater than the upper temperature limit, controlling a power output of the induction coil to a non-zero value configured to allow the first temperature to decrease toward the targeted temperature.
A rethermalizing station comprising:
- a well;
- a plurality of food pans configured to be positioned in the well;
- an induction coil, wherein the induction coil is a side induction coil extending around a perimeter of the well;
- a plurality of moveable bottom induction coils configured to be repositioned in the well for alignment with the plurality of food pans;
- and
- processing circuitry configured to perform operations comprising controlling the induction coil without using an on/off duty cycle by:
- responsive to a determination that a food pan acceptable for use with the induction coil is positioned at the rethermalizing station, comparing a measured temperature of the food pan to an upper temperature limit defined as a function of a selected temperature;
- and
- if the measured temperature of the food pan is greater than the upper temperature limit, controlling a power output of the induction coil to a non-zero value configured to allow the measured temperature to decrease toward the selected temperature.
A method of operating a rethermalizing station comprising a well, a plurality of food pans configured to be positioned in the well, an induction coil extending around a perimeter of the well, and a plurality of moveable bottom induction coils configured to be repositioned in the well for alignment with the plurality of food pans, the method comprising controlling the induction coil without using an on/off duty cycle by:
- receiving a selected targeted temperature;
- defining an upper temperature limit as a function of the selected targeted temperature;
- automatically comparing a measured temperature of a food pan of the plurality of food pans to the upper temperature limit;
- and
- if the measured temperature of the food pan is greater than the upper temperature limit, controlling a power output of the induction coil to a non-zero value configured to allow the measured temperature to decrease toward the selected targeted temperature.
Dependencies are inferred from the claim text.