Abstract:
Embodiments of the present disclosure relate generally to a system that improves heat distribution throughout an internal cooking cavity of an oven. The embodiments described may find particular use in ovens used on-board passenger transport vehicles, but they may also be incorporated into other ovens, such as residential and other commercial ovens.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application Ser. No. 61/733,257, filed Dec. 4, 2012, titled “Temperature Control System,” the entire contents of which are hereby incorporated by reference. 
    
    
     FIELD OF THE DISCLOSURE 
     Embodiments of the present disclosure relate generally to a system that improves heat distribution throughout an internal cooking cavity of an oven. The embodiments described may find particular use in ovens used on-board passenger transport vehicles, but they may also be incorporated into other ovens, such as residential and other commercial ovens. 
     BACKGROUND 
     Currently, cooking cavity temperatures are monitored by a temperature sensor that is located at the back of the cavity. Typically, this sensor is located behind the baffle plate that separates the meals that are contained inside the cavity from the oven&#39;s hardware, such as the heating elements and the blower wheel. The temperature sensor is designed to turn the heating elements on and off, depending upon the temperature of the cooking cavity. This can be referred to as “cycling” of the oven. 
     The baffle plate is designed to control air distribution in the cooking cavity. It may have an opening in the middle that pulls in air from the cooking cavity. Heated air can then be allowed to travel around sides of the baffle plate, back to the cooking cavity in order to create an air loop. 
     In one aspect, the temperature sensor can be programmed to prompt the heaters to switch off at a pre-set temperature. Because the rear of the oven (which is where the sensor and the heating elements are located) will heat more quickly than the interior of the cooking cavity, this pre-set temperature is generally lower than the temperature of the rest of the cooking cavity. This means that shutting off the heating elements at the pre-set temperature results in uneven temperatures throughout the cooking cavity. The ambient temperature behind the baffle plate does not reflect the ambient temperature in the rest of the cooking cavity, as the temperature in this area may be considerably higher than the rest of the cooking cavity. In this scenario, the temperatures at the front of the cooking cavity are lower than the temperatures at the back of the cooking cavity. This can result in large variations of meal temperatures, longer cooking times, and variations in meal quality. 
     BRIEF SUMMARY 
     Embodiments described herein thus provide a system to measure the temperature at various locations in the cooking cavity and to adjust the temperature at which the heating elements turn on and off. Embodiments of this disclosure seek to improve the temperature variations in meals by creating a more uniform cooking cavity temperature for the duration of the cooking cycle. Multiple temperature sensors are provided in order to determine an average oven temperature from points measured at multiple areas of the cooking cavity. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a side schematic view of a cooking cavity with a rear temperature sensor. 
         FIG. 2  top perspective view of an improved cooking cavity having multiple temperature sensors. 
         FIG. 3  is a flowchart illustrating the signals communicated between various elements of the cooking cavity. 
         FIG. 4  shows how the temperature sensors communicate with a communication system and a controller. 
     
    
    
     DETAILED DESCRIPTION 
     Ovens for use on board aircraft are generally used to re-heat meals. According to aircraft regulations, the meals should be heated to a minimum temperature, generally above about 70° C. In order to comply with this requirement, aircraft ovens may need to run longer than necessary in order to have all meals heated to this temperature. One problem this creates is that some meals will be heated to temperatures that are higher than desired, which can result in meal degradation. Similar situations can occur with other residential and commercial ovens. 
     As shown in  FIG. 1 , the temperature of a cooking cavity  10  is measured by a temperature sensor  12  that is positioned in the cooking cavity  10  behind a baffle plate  14 . This sensor may be referred to herein as a rear temperature sensor  12 . The rear temperature sensor  12  is provided to measure the temperature of an area around the oven hardware, such as the one or more heating elements  16  and the motor  18 . If this area is allowed to rise above a specified temperature, damage to the hardware can occur. Accordingly, the rear temperature sensor  12  is generally set to shut off at a pre-set value. In the examples that follow, the pre-set valve will be described as 200° F., but this value is used for exemplary purposes only. The pre-set value may be set dependent upon the heat resistance of the hardware and any applicable regulations. 
     If the pre-set value is 200° F., and the rear temperature sensor  12  senses a 200° F. temperature in the sensing area, it will trigger a control system to turn off the heating element(s)  16 . However, when the temperature in the sensing area behind the baffle plate  14  is 200° F., it is likely that the area of the cooking cavity  10  in front of the baffle plate  14  is not that high. Variations of up to several degrees can occur. 
     Accordingly, the present disclosure provides one or more front temperature sensors  20 ,  22  at areas in the cooking cavity  10  in front of the baffle plate  14 . One example is shown in  FIG. 2 . In one embodiment, a single temperature sensor  20  may be provided. In other embodiments, two temperature sensors  20 ,  22  may be provided. In other embodiments, further temperature sensors may be provided at other areas of the cavity  10 . The purpose of the one or more front temperature sensors is to measure the temperature at the surrounding areas in front of the baffle plate  14 . This sensor (or these sensors) will sense the true temperature in the cooking cavity  10 . As shown in  FIG. 2 , a first temperature sensor  20  may be located at a front side of the cavity  10 . A second temperature sensor  22  may be located at a side wall of the cavity  10 . They may be positioned diagonally from one another, both at the front, both at the sides, at an upper portion of the cavity, at a lower portion of the cavity, or at any other appropriate location for optimal temperature sensing. 
     The value recorded by the rear temperature sensor  12  can be combined with the value recorded by the one or more front temperature sensors  20 ,  22  in order to determine an optimal shut off point for the heating element(s)  16 . This combination may be run by an algorithm or formula that will account for various variables, including optimal cooking temperature and an optimal working temperature for the hardware. Thus, rather than shutting off at a pre-set value, the heating elements  16  can be allowed to continue to heat until a more optimal temperature in the cooking cavity  10  has been reached, based on information obtained from various data points in the cooking cavity  10 . 
     In one method  300  as illustrated in the flowchart of  FIG. 3 , the rear temperature sensor  12  senses the temperature behind the baffle plate  14 , as depicted in  310 . The one or more front temperature sensors  20 ,  22  sense temperature in front of the baffle plate  14 , as depicted in  320 . The rear temperature sensor  12  sends input about the sensed temperature value to a communication system, as depicted in  330 . The one or more front temperature sensors also send input about the sensed temperature value to a communication system, as depicted in  340 . As depicted in  350 , the communication system receives input from both the rear temperature sensor  12  and the one or more front temperature sensors  20 ,  22 . The communication system then compares the inputs and determines an optimal shut-off value, as depicted in  360 . The communication system sends instructions to a controller for controlling the activation of the one or more heating elements upon receipt of instructions from the communication system, as depicted in  370 . 
     In short, temperature data and/or measured variable(s) from the one or more front temperature sensors  20 ,  22  will be combined with temperature data and/or measured variable(s) from the rear temperature sensor  12  in order to determine an optimal temperature value, rather than simply using an automatic pre-set value. The communication system can run an algorithm designed to optimize the temperature and the point at which the heating elements should be cycled (i.e., turned on and/or off). The controller then implements the instructions from the communication system. The controller and the communication system may be designed to be integral with the oven, such that they are components installed with or near the oven. In other embodiments, the controller and the communication system may be designed to be remote from the oven, such that they compute and control at a distance away from the oven and relay instructions back to the oven. They may be connected with a wired connection or a wireless connection, either to one another and/or to the oven cooking cavity. 
     As shown in the schematic information flow of  FIG. 4 , the system  400  may have a rear temperature sensor  410  that sends a sensed value to a communication system  430 . One or more front temperature sensors  420  may send a sensed value to the communication system  430 . The communication system  430  may then run an algorithm or formula or program that is delivered to the controller  440 . The controller  440  then controls cycling of the heating elements (i.e., controls turning the heating elements remain on and/or off in order to achieve the desired optimal temperature value). 
     It is possible to create the algorithm so that the rear temperature sensor  410  is the master and the one or more front temperature sensors  420  are slaves. This results in the rear temperature sensor being the controlling factor in the equation, but being adjustable based on the values sensed by the slave sensors  420 . 
     Changes and modifications, additions and deletions may be made to the structures and methods recited above and shown in the drawings without departing from the scope or spirit of the invention and the following claims.