Control system for an aircraft galley cooler
First Claim
1. A method for regulating the air temperature in a food cart within an aircraft galley system, the galley system including a galley air cooling unit having the food cart and a galley plenum therein, the plenum including a heat exchanger, a fan which blows air across the heat exchanger, into the food cart via an air supply duct coupling the plenum to the food cart and back into the plenum via an air return duct coupling the food cart to the plenum, an air supply temperature sensor for measuring the temperature of the air entering the food cart from the plenum, and an air return temperature sensor for measuring the temperature of the air entering the plenum from the food cart, the method utilizing a control system for performing the steps including:
- regulating the return air temperature to a selected set point by controlling the amount of a liquid refrigerant flowing through the heat exchanger via a valve;
regulating the supply air temperature if the return air temperature sensor fails, regulating the supply air temperature including, regulating the supply air temperature between a preset bottom threshold and a preset top threshold, closing the valve completely if the supply air temperature falls below the preset bottom threshold, opening the valve when the supply air temperature rises to the preset top threshold, and resuming regulation of the supply air temperature between the preset bottom threshold and the preset top threshold; and
temporarily discontinuing regulation of the return air temperature if the supply air temperature drops below the preset bottom threshold, including, closing the valve completely until the supply air temperature increases to the preset top threshold, and resuming regulation of the return air temperature.
8 Assignments
0 Petitions
Accused Products
Abstract
An aircraft galley air cooling system utilizes a controller having software for regulating the temperature within food carts within a galley air cooling unit. The cooling unit includes supply air and return air temperature sensors which measure the temperature of the air entering and exiting the food cart. The return air temperature is regulated by controlling the amount of a liquid refrigerant that flows through a heat exchanger within the cooling unit. If the return air temperature sensor fails, then the controller regulates the supply air temperature. The controller also regulates defrosting of the cooling unit.
117 Citations
17 Claims
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1. A method for regulating the air temperature in a food cart within an aircraft galley system, the galley system including a galley air cooling unit having the food cart and a galley plenum therein, the plenum including a heat exchanger, a fan which blows air across the heat exchanger, into the food cart via an air supply duct coupling the plenum to the food cart and back into the plenum via an air return duct coupling the food cart to the plenum, an air supply temperature sensor for measuring the temperature of the air entering the food cart from the plenum, and an air return temperature sensor for measuring the temperature of the air entering the plenum from the food cart, the method utilizing a control system for performing the steps including:
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regulating the return air temperature to a selected set point by controlling the amount of a liquid refrigerant flowing through the heat exchanger via a valve;
regulating the supply air temperature if the return air temperature sensor fails, regulating the supply air temperature including, regulating the supply air temperature between a preset bottom threshold and a preset top threshold, closing the valve completely if the supply air temperature falls below the preset bottom threshold, opening the valve when the supply air temperature rises to the preset top threshold, and resuming regulation of the supply air temperature between the preset bottom threshold and the preset top threshold; and
temporarily discontinuing regulation of the return air temperature if the supply air temperature drops below the preset bottom threshold, including, closing the valve completely until the supply air temperature increases to the preset top threshold, and resuming regulation of the return air temperature. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for regulating the air temperature in a food cart within an aircraft galley system, the galley system including a galley air cooling unit having the food cart and a galley plenum therein, the plenum including a heat exchanger, a valve to control the flow of a liquid refrigerant through the heat exchanger, a fan which blows air across the heat exchanger, into the food cart via an air supply duct coupling the plenum to the food cart and back into the plenum via an air return duct coupling the food cart to the plenum, an air supply temperature sensor for measuring the temperature of the air entering the food cart from the plenum, and an air return temperature sensor for measuring the temperature of the air entering the plenum from the food cart, the galley air cooling unit having a galley air cooling switch for turning the galley air cooling unit on, a proximity switch which indicates the presence of a food cart within the galley air cooling unit, and a liquid refrigerant indicator which indicates whether the liquid refrigerant is sufficiently cool to regulate the air temperature in the galley air cooling unit, the method utilizing a control system for performing the steps including:
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turning the fan on when the galley air cooling unit switch is transitioned to ON;
running the fan for a preset duration of time after the galley air cooling unit switch is transitioned to ON;
turning the fan off if the galley air cooling unit switch is transitioned to OFF prior to the expiration of the preset duration of time;
opening the valve partially at the expiration of the preset duration of time if the galley air cooling unit switch remains in the ON position, regulating the valve if, the galley air cooling unit switch is ON, the proximity switch indicates that a food cart is within the galley air cooling unit, and either the liquid refrigerant indicator indicates that the liquid refrigerant is sufficiently cool to regulate the air temperature in the galley air cooling unit or the liquid refrigerant is at least 2°
C. (4°
F.) below the selected set point;
closing the valve and turning the fan off if any of the following conditions are met, the galley air cooling unit switch is turned OFF, the proximity switch indicates that there is not a food cart within the galley air cooling unit, or both the liquid refrigerant indicator indicates that the liquid refrigerant is not sufficiently cool to regulate the air temperature in the galley air cooling unit and the liquid refrigerant is at least 6°
C. (10°
F.) above the selected set point;
regulating the return air temperature to a selected set point by controlling the amount of the liquid refrigerant flowing through the heat exchanger via the valve;
regulating the supply air temperature if the return air temperature sensor fails, regulating the supply air temperature including, regulating the supply air temperature between a preset bottom threshold and a preset top threshold, closing the valve completely if the supply air temperature falls below the preset bottom threshold, opening the valve when the supply air temperature rises to the preset top threshold, and resuming regulation of the supply air temperature between the preset bottom threshold and the preset top threshold; and
temporarily discontinuing regulation of the return air temperature if the supply air temperature drops below the preset bottom threshold, including, closing the valve completely until the supply air temperature increases to the preset top threshold, and resuming regulation of the return air temperature.
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Specification