Temperature Sensor for a Food Holding Cabinet
AssigneePrince Castle LLC
InventorsTerry Tae-Il Chung, Jeff Schroeder, Kerry Berland, Douglas Reinking
Life of this patent
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Abstract
The temperature of shelves used in a food holding cabinet are measured using a transistor. The voltage across a PN junction being known to be temperature dependent, the shelf temperature can be inferred from a calculated temperature of a PN junction of a transistor thermally coupled to a heated or refrigerated shelf. No calibration of the measurement device is required since the PN junction voltage, current and temperature relationship is well known.
Claims35
A temperature sensor for a food holding cabinet, the temperature sensor comprised of:
- a semiconductor, comprised of a PN junction;
- circuit board having first and second sides, the semiconductor being mounted to the first side of the circuit board, the second side being at least partially coated with a thermally-conductive layer;
- and
- a thermally-conductive via extending through the circuit board, the via having a first end thermally coupled to the thermally-conductive layer and a second end substantially co-planar with the first side of the circuit board.
A food holding cabinet (cabinet) comprised of:
- a food holding compartment;
- a thermally-conductive surface (surface) within the compartment;
- a heat transfer device, exchanging heat energy with the surface;
- a semiconductor temperature sensor (temperature sensor), thermally coupled to the surface.
A temperature sensor for a food holding cabinet, the sensor comprised of:
- a first circuit board having a thickness, top and bottom surfaces and a hole that extends through the top and bottom surfaces;
- a second circuit board having top and bottom surfaces and having a transistor mounted to the top surface thereof, the second circuit board being mounted to the first circuit board such that, at least part of the transistor is within the hole, between the top and bottom surfaces of the first circuit board.
A temperature-controlled food holding cabinet (food holding cabinet) comprised of:
- a thermally-conductive shelf for supporting foods to be kept warm, the shelf having first and second sides;
- a heating element thermally coupled to the thermally-conductive shelf (shelf);
- a temperature sensor thermally coupled to at least the second surface of the conductive shelf, the temperature sensor measuring temperature and providing an output signal equivalent thereto.
A method of attaching a semiconductor temperature sensor to a thermally-conductive shelf (shelf) for a food holding cabinet, the shelf having first and second opposing sides, the method comprising the steps of:
- attaching a first circuit board to a first side of the shelf, the first circuit board having a hole that extends through said first circuit board;
- applying an adhesion layer over at least part of the first side of the shelf and over part of the first circuit board such that the hole through the first circuit board and a first area of the first circuit board surrounding the hole, remains uncoated by the adhesion layer after application of the adhesion layer;
- after the adhesion layer is applied, attaching a second circuit board to the first circuit board within the first area of the first circuit board, the second circuit board having a temperature-sensing transistor mounted thereon;
- whereby when the second circuit is attached to the first circuit board, the transistor is within the hole and proximate the first side of the shelf.
Dependencies are inferred from the claim text.