Patent Application
20090044547
This application relates generally to food and beverage refrigeration and more particularly, to food and beverage refrigeration systems that alter airflow to maintain uniform temperatures.
Maintaining a relatively uniform temperature is important in any refrigeration system, but it is particularly important in the context of food and beverage refrigeration. Without proper temperature distribution, some food in a refrigerator will be too cold, resulting in unwanted freezing and some will be too warm, which raises the risk of spoilage. In most contexts, a uniform temperature is not only desirable, but is mandated by regulations. For example, depending upon the aircraft operating authority certain types of food served on passenger airlines is required to be maintained at a maximum temperature of no more than 7° C. and in some countries 4° C.
Typically, pre-prepared airline food is stored in galley carts prior to serving to passengers. However, current galley cooling systems have to force air just above freezing either into the galley carts or into insulated compartments containing several galley carts just to ensure that the temperature does not exceed the required temperature in any portion of the carts. This is due to the temperature increase as the air passes through or over the galley carts to remove the heat entering the galley cart or compartment. The lower maximum temperature requirement of 4° C means that the current cold air source is less efficient resulting in the need to use more powerful and heavier systems that use more electrical power. Thus, it can be seen that there is a need for a new method and apparatus for maintaining a uniform temperature in a refrigeration system.
In accordance with the foregoing, a method and apparatus for maintaining a uniform temperature in a refrigeration system is provided. According to an embodiment of the invention, the method involves directing chilled air through a galley cart or compartment in a first direction, switching the flow of the chilled air to a second direction (substantially opposite the first direction), and periodically repeating these steps. In another embodiment, the apparatus includes an air chiller, a storage enclosure defining a compartment, a duct system, and a valve system. The air chiller blows chilled air into the duct system. The compartment has a first and a second opening, each of which is coupled to the duct system. The valve system has valves that can be moved to route the chilled air so that it enters into the first opening and exits the second opening, or vice versa. In one embodiment, the first opening is at the top of the compartment and the second opening is at the bottom of the compartment, and the valve system is controlled by a control circuit that periodically switches the valves (via an actuator) to change the direction of the chilled air. This effectively maintains a relatively uniform temperature throughout the compartment.
Referring to
Protruding from the first and second side walls 30 and 32, are rails 38, which are configured to hold food trays. The enclosure 12 also has a divider 40 attached to the first and second side walls 30 and 32. The divider 40 is disposed at or about the vertical midway point of the side walls 30 and 32. The divider 40 has a pair of generally V-shaped cutouts 42, one proximate to the door 20 and one proximate to the back wall 28. The back wall 28 has a pair of generally square openings, a first opening 43 and a second opening 45, in which a first grill 44 and a second grill 46 are disposed. The first and second openings 43 and 45 link the storage compartment 24 with the outside of the enclosure 12, allowing air to move in or out through the grills 44 and 46.
The first grill 44 is located proximate to the ceiling 34 while the second grill 46 is located proximate to the floor 36. The first and second grills 44 and 46 permit air to flow through the back wall 28.
Referring to
The duct system 106 has a main duct 112 that extends around the inner periphery of the cart corral 102. The main duct 112 starts at the inlet 108 of the duct system 106 and terminates at the outlet 110 of the duct system 106.
The cart corral 102 has an open side 114 that enables a cart to be parked within the corral 102.
In addition to the main duct 112, the duct system 106 includes a first branch 116 and a second branch 118. The first branch 116 has openings 120 that are next to or coupled with the first openings 43 of the carts 10. Similarly, the second branch 118 has openings 122 that are next to or coupled with the second openings 45 of the carts 10.
Disposed within the duct system 106 is a valve system, which includes a first valve 124 and a second valve 126. The refrigeration system 100 also includes a control unit 128. The control unit 128 includes a control circuit 130, which controls the movement of the first and second valves 124 and 126 by sending signals to an actuator that is mechanically coupled to the first and second valves 124 and 126. The first valve 124 has at least two positions—a first position, shown in
The refrigeration system 100 has at least two modes of operation—a normal airflow mode and a reversed airflow mode. The normal airflow mode will now be described with respect to
The reverse airflow mode will now be described with reference to
According to an embodiment of the invention, the refrigeration system periodically switches from the normal airflow mode to the reverse airflow mode. The time interval for switching the airflow can depend on many factors, such as the desired temperature of the system, and may also depend upon a sensed temperature of the system. This could include, for example, temperature sensors that determine whether there is a difference between the temperature at the top of a cart as compared to the temperature at the bottom of a cart. If such a difference exceeds a particular threshold, the airflow may be switched to provide more uniform cooling. In one implementation, the switching may occur periodically from 2 to 30 minutes. The switching between the normal mode and the reverse mode is controlled by the control circuit 130 of the control unit 128. Periodically reversing the flow of air helps to equalize the temperature throughout the compartment 24.
As should be appreciate by one of skill in the art, the foregoing describes an embodiment where 3 different carts are accommodated within the cooling system of the present invention. The same invention may be readily implemented with respect to more or less carts. For example, the invention may be implemented with respect to just one cart, where 2 valve are operated to direct airflow through the cart initially in one direction, then to direct airflow through the cart in the other direction.
It can be seen from the foregoing that a new and useful method and system for identifying and managing currency exposure has been described. The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
