Abstract:
A temperature control system for controlling the rate of flow of a flammable fluid at generally constant pressure is disclosed. The system may include a flow control apparatus that is free of a regulator mechanism, for affecting the flow of the fluid. The flow control apparatus may be operable between at least a first flow rate and a second flow rate, and may have at least one upstream opening and at least one downstream opening. The system may also include a first burner in fluid communication with the downstream opening of the flow control apparatus and a conduit in fluid communication at one end thereof with the upstream opening of the flow control apparatus, and configured at the other end thereof for connection to a fuel supply. A thermocouple may be located in the vicinity of the burner, for converting a sensed thermal state into an electrical signal. An electronic controller, in communication with the flow control apparatus, for activating the flow control apparatus to one of said first and second flow rates, and being in communication with the thermocouple for receiving the electrical signal from the thermocouple is also provided. An interface connected to the controller for manually inputting a desired temperature may be included, wherein the controller is operable to automatically cycle the flow control apparatus between the first and second flow rates until the temperature sensed by the thermocouple is similar to the desired temperature.

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 12/000,163 filed Dec. 10, 2007 now U.S. Pat. No. 7,793,649, which claims priority from PCT/CA2007/002085 filed Nov. 16, 2007, both of which are incorporated herein by reference in their entirety for all purposes. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a temperature control apparatus for a cooking apparatus, and is particularly concerned with a TEMPERATURE CONTROL APPARATUS AND METHOD FOR A BARBEQUE grill or similar apparatus. 
     BACKGROUND OF THE INVENTION 
     Traditionally, barbecues, grills and other typically outdoor cooking apparatus have not included means for automatically managing the temperature of an interior of the apparatus. Control of temperature is often managed manually by observation (or sensing) of a temperature state of the cooking apparatus, and manually adjusting the temperature to attempt to achieve a desired temperature. 
     SUMMARY OF THE INVENTION 
     In accordance with a broad aspect of the present invention there is provided a temperature control system for controlling the rate of flow of a flammable fluid at generally constant pressure. The system may include a flow control apparatus that is free of a regulator mechanism, for affecting the flow of the fluid. The flow control apparatus may be operable between at least a first flow rate and a second flow rate, and may have at least one upstream opening and at least one downstream opening. The system may also include a first burner in fluid communication with the downstream opening of the flow control apparatus and a conduit in fluid communication at one end thereof with the upstream opening of the flow control apparatus, and configured at the other end thereof for connection to a fuel supply. A thermocouple may be located in the vicinity of the burner, for converting a sensed thermal state into an electrical signal. An electronic controller, in communication with the flow control apparatus, for activating the flow control apparatus to one of said first and second flow rates, and being in communication with the thermocouple for receiving the electrical signal from the thermocouple is also provided. An interface connected to the controller for manually inputting a desired temperature may be included, wherein the controller is operable to automatically cycle the flow control apparatus between the first and second flow rates until the temperature sensed by the thermocouple is similar to the desired temperature. The system is free of a regulator between an upstream end of the conduit and the burner. 
     In an embodiment of the present invention the controller is pre-programmed with a first temperature set point and a second temperature set point relative to the desired temperature input by the user, and the controller is pre-programmed to automatically cycle the flow control apparatus between the first flow rate when the thermocouple communicates a temperature above said second set point, and the second flow rate when the thermocouple communicates a temperature below said first set point. 
     Conveniently, the controller may be pre-programmed with a first temperature set point and a second temperature set point relative to the desired temperature input by the user, and the controller is pre-programmed to automatically cycle the flow control apparatus between the first flow rate when the thermocouple communicates a temperature above said second set point, and the second flow rate when the thermocouple communicates a temperature below said first set point. 
     According to another broad aspect, the system may include at least one manually controllable valve located between the upstream end of the conduit and the burner, the at least one manually controllable valve having a total minimum flow rate generally equal to the first flow rate of the flow control apparatus. The system may also include at least one of a solenoid valve and a latch valve. 
     The system may be part of a barbecue grill assembly having and enclosure, the thermocouple and burner being mounted within the enclosure. 
     According to another aspect, a second flow control apparatus operable between at least a third flow rate and a fourth flow rate, and having at least one upstream opening and at least one downstream opening may be provided. The second flow control apparatus may be in fluid communication at the upstream opening thereof with the fuel supply. The system may also include a second burner in fluid communication with the downstream opening of the second flow control apparatus, and a second thermocouple, located in the vicinity of the second burner, for converting a sensed thermal state into an electrical signal. The controller may be in communication with the second flow control apparatus and is capable of activating said flow control apparatus to one of said third and fourth flow rates. The controller may also be in communication with the second thermocouple for receiving the electrical signal from the second thermocouple. The interface may be configured for manually inputting a second desired temperature, and the controller may be operable to automatically cycle the second flow control apparatus between the third and fourth flow rates until the temperature sensed by the second thermocouple is similar to the second desired temperature. 
     According to another broad aspect, the system may include a divider located adjacent the first and second burners for thermally inhibiting transference of a thermal output of the first and second burners through the divider. 
     In another aspect, the controller may include at least one additional pair of set points, each additional pair corresponding to a different possible temperature input by the user. 
     In accordance with another broad aspect, there may be provided a divider system for inhibiting heat transfer within an enclosed volume of a gas barbeque, wherein the enclosed volume defined by an openable lid and a base, and the base supports a grill having openings therein for permitting the passage of thermal energy. The divider may include a nonflammable rigid sheet having a low thermal conductivity and a perimeter which is defined to generally conform to a cross-section of the enclosed volume in a plane generally perpendicular to said grill. The sheet may include at least one rebate therein for receiving at least one of the grill and the base to permit placement of the divider into the barbeque and to permit closure of the lid to thermally sub-divide the enclosed volume. 
     In an embodiment, the divider may include a support feature mounted thereto for abutting at least one of an edge of the base and the grill to inhibit lateral movement of the divider when installed within the enclosure. 
     In a further embodiment, the divider may include the support feature extends generally perpendicular to the divider to lie flush with at least one of the base and the grill when installed within the enclosure. 
     In a yet further embodiment, the divider may include a support feature mounted to at least one of the base and the grill for abutting the rigid sheet to inhibit lateral movement of the divider when installed within the enclosure. The feature may be a slot defined in the base for receiving and edge of the rigid sheet. Alternatively, the divider is permanently mounted to at least one of the base and grill. The divider may also include a rebate defined therein for receiving a feature of the barbeque, and the feature may be a warming rack. 
     In a further aspect, the rebate may be defined by a tongue of the divider, wherein the tongue extends into a volume defined by the base. 
     According to another broad aspect, there is provided a support for a fuel container including a base defining a receptacle for receiving an end of the fuel container, wherein the receptacle is a shape generally complimentary to the end. There may also be provided a fuel level sensor retainer within the base for receiving and positioning a fuel level sensor in abutting relationship with the fuel container when the fuel container is placed within the receptacle. 
     According to a yet further broad aspect there is provided a method for controlling the rate of flow of a flammable fluid at generally constant pressure using a flow control apparatus, and the flow control apparatus is free of a regulator mechanism and settable at one of a first flow rate and a greater second flow rate. This may be used to achieve a desired temperature within a cooking apparatus having at least one volume defined therein. The method may include the steps of:
         assessing whether the flow control apparatus is to be automatically controlled;   when the flow control apparatus is to be automatically controlled:
           assessing the temperature within the cooking apparatus;   maintaining the flow state of the flow control apparatus when the temperature within the cooking apparatus is within the range of about:
               (i) an upper threshold value, which upper threshold value is greater than the desired temperature, and   (ii) a lower threshold value, which lower threshold value is less than the desired temperature;   
               assessing whether the temperature within the cooking apparatus is generally higher than the upper threshold value; and   
           setting the flow control apparatus to the first flow rate when the temperature within the cooking apparatus is generally higher than the upper threshold value.       

     In an embodiment, the method may further include the step of assessing whether the temperature within the cooking apparatus is generally lower than the lower threshold value; and setting the flow control apparatus to a second flow rate when the temperature within the cooking apparatus is generally lower than the lower threshold value. 
     In a further embodiment, the method may further include the step of assessing whether a safety condition occurs; and setting the flow control apparatus to a first flow rate when the safety condition occurs. 
     Conveniently, the method may further include the step of: assessing whether the flow control apparatus is to be manually controlled; and setting the flow control apparatus to a second flow rate when the flow control apparatus is to be manually controlled. 
     Conveniently, the method may further include the step of: activating an alarm when a safety condition occurs. 
     In another aspect the upper threshold value may be about two degrees Fahrenheit greater than the desired temperature. 
     One or more of the steps may be repeated. 
     Further, one or more of the assessing steps may be repeated every one to sixty seconds. Alternatively, one or more of the steps are repeated sequentially. 
     In a further aspect, the step of assessing the safety condition may include at least one of:
         assessing whether the temperature of the cooking vessel is about or higher than a predetermined safety threshold temperature;   assessing whether the rate of increase in temperature is about or greater than a predetermined safety temperature increase rate; and   assessing whether the rate of decrease in temperature is about or less than a predetermined safety temperature decrease rate.       

     Additionally, the method may further include the step of making the desired temperature equal to a lower keep warm temperature after a predetermined period of time has elapsed. 
     Conveniently, the cooking apparatus may include a second volume defined therein, and a second flow control apparatus for achieving a second desired temperature within the second volume, the method further include the steps of:
         assessing whether the second flow control apparatus is to be automatically controlled;   when the second flow control apparatus is to be automatically controlled:
           assessing the temperature within the second volume;   maintaining the flow state of the second flow control apparatus when the temperature within the second volume is within the range of about:
               (i) an second upper threshold value, which second upper threshold value is greater than the second desired temperature, and   (ii) a second lower threshold value, which second lower threshold value is less than the second desired temperature;   
               assessing whether the temperature within the second volume is generally higher than the second upper threshold value; and   setting the second flow control apparatus to the first flow rate when the temperature within the cooking apparatus is generally higher than the upper threshold value.   
               

     In a yet further broad aspect, there may be provided a temperature control device for controlling a flow control apparatus that controls the rate of flow of a flammable fluid at generally constant pressure to heat a cooking apparatus to a desired temperature, the device may include:
         a microprocessor for controlling operation of the flow control apparatus;   an interface connected to the microprocessor for manually inputting the desired temperature; and   a memory coupled to the microprocessor;
 
the temperature control device including a temperature control module resident in memory for execution by the microprocessor, the module being configured to:
   assess the temperature within the cooking apparatus;   maintain the flow state of the flow control apparatus when the temperature within the cooking apparatus is within the range of about:
           (i) an upper threshold value, which upper threshold value is greater than the desired temperature, and   (ii) a lower threshold value, which lower threshold value is less than the desired temperature;   
           assess whether the temperature within the cooking apparatus is generally higher than the upper threshold value; and
 
set the flow control apparatus to the first flow rate when the temperature within the cooking apparatus is generally higher than the upper threshold value.
       

     Additionally, the device may be additionally configured to: assess whether the temperature within the cooking apparatus is generally lower than the lower threshold value; and set the flow control apparatus to a second flow rate when the temperature within the cooking apparatus is generally lower than the lower threshold value. 
     In a further embodiment, the device may be additionally configured to: make the desired temperature equal to a lower keep warm temperature after a predetermined period of time has elapsed. The device may also include a storage device coupled to the microprocessor. 
     According to a yet further broad aspect, there may be provided a computer program product having a computer readable medium tangibly embodying code for activation of a temperature control device, the computer program product include:
         code for assessing the temperature within the cooking apparatus;   code for maintaining the flow state of the flow control apparatus when the temperature within the cooking apparatus is within the range of about:
           (i) an upper threshold value, which upper threshold value is greater than the desired temperature, and   (ii) a lower threshold value, which lower threshold value is less than the desired temperature;   
           code for assessing whether the temperature within the cooking apparatus is generally higher than the upper threshold value; and   code for setting the flow control apparatus to the first flow rate when the temperature within the cooking apparatus is generally higher than the upper threshold value.       

     Additionally, the computer program product may further include code for assessing whether the temperature within the cooking apparatus is generally lower than the lower threshold value; and code for setting the flow control apparatus to a second flow rate when the temperature within the cooking apparatus is generally lower than the lower threshold value. 
     Additionally, the computer program product may further include code for making the desired temperature equal to a lower keep warm temperature after a predetermined period of time has elapsed. 
     Other and further advantages and features of the invention will be apparent to those skilled in the art from the following detailed description of embodiments thereof, taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The present invention will be further understood from the following detailed description of embodiments of the invention, with reference to the drawings in which: 
         FIG. 1  is an isometric view of a barbecue including a temperature control apparatus; 
         FIG. 2  is an isometric view of the barbecue of  FIG. 1  with a lid of the barbecue removed to reveal a grill and divider; 
         FIG. 3  is a schematic diagram of components included in the temperature control apparatus, and components related thereto; 
         FIG. 4A  is a cross-sectional view of a solenoid valve in a closed position; 
         FIG. 4B  is a cross-sectional view of the solenoid valve of  FIG. 4A  in an open position; 
         FIGS. 5A to 5P  illustrate various features of an embodiment of a liquid crystal display of the temperature control apparatus; 
         FIG. 6  is an isolated isometric view of the barbecue of  FIG. 1  showing a console, burners, and temperature control apparatus; 
         FIG. 7  is a partial rear view of  FIG. 6 ; 
         FIG. 8  is an isometric view of the barbecue of  FIG. 1  showing a tank support; 
         FIG. 8A  is an enlarged view of a tank sensor of  FIG. 8 ; 
         FIGS. 9A to 9D  include various views of a tank sensor of  FIG. 8 ; 
         FIG. 10  illustrates an isometric view of the barbecue of  FIG. 1  illustrating a tank support in an extended position; 
         FIG. 10A  is an enlarged view of the tank support of  FIG. 10 ; 
         FIG. 11A  is an isolated isometric view of the tank support of  FIG. 10 ; 
         FIGS. 11B to 11D  present different isolated views of the tank support of  FIG. 10  and a shelf of the barbecue of  FIG. 10 ; 
         FIG. 12  is an enlarged cross-sectional view of the tank support of  FIG. 10  having a tank placed therewithin; 
         FIG. 13  is an isometric view of the barbecue of  FIG. 1  with a lid thereof removed to reveal a divider; 
         FIG. 13A  is an enlarged view of the divider of  FIG. 13 ; 
         FIGS. 13B to 13D  are various views of the barbecue of  FIG. 13  and the divider therein; 
         FIG. 14  is an isolated isometric view of the divider of  FIG. 13 ; 
         FIG. 15  is an isometric view of the barbecue of  FIG. 1  and a storage receptacle; 
         FIG. 15A  is an enlarged view of the receptacle of  FIG. 15 ; 
         FIGS. 16A to 16D  present various isolated views of the storage receptacle, insert and slide rails of  FIG. 15 ; 
         FIG. 17  is an isometric view of the barbecue of  FIG. 1  and a grease receptacle; 
         FIG. 17A  is an enlarged view of the receptacle of  FIG. 17 ; 
         FIGS. 18A to 18D  are isolated views of a shelf and receptacle of the barbecue of  FIG. 17 ; 
         FIG. 19  is an isolated isometric view of the barbecue of  FIG. 2  showing an infrared burner; 
         FIG. 19A  is an enlarged view of the infrared burner of  FIG. 19 ; 
         FIGS. 20A to 20D  are isolated views of the infrared burner of  FIG. 19 ; and 
         FIG. 21  is a schematic flow diagram of aspects of the function of the temperature control device. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Similar references are used in different figures to denote similar components. The disclosed temperature control apparatus may facilitate control of an internal temperature of a gas fuelled appliance, such as an outdoor gas barbeque. The description herein is made in the context of a gas fuelled barbeque, but the disclosed temperature control apparatus may be applied to any manner of appliance, including gas fuelled appliances. 
     In general, the temperature control apparatus permits a user to input a desired temperature set-point. The temperature control apparatus then automatically controls the flow rate of gas into the barbeque to achieve the desired temperature. This may permit greater precision in the cooking of food with a gas fuelled appliance. For example, more accurate and automatic temperature control may permit a barbeque to be used to bake, in addition to a more traditional grilling of meat. Even the grilling of meat may be improved given that an operator or user has the assistance of a somewhat automated control of the temperature within the barbeque. Such greater diversity of food that may be cooked with a barbeque may have certain advantages, such as encouraging a greater number of women to use a barbeque for cooking. 
       FIG. 1  illustrates a barbeque  20 , which may be a typical barbeque. Barbeque  20  may include an openable lid  22  mounted to a base  24 . 
       FIG. 2  illustrates the barbeque  20  having lid  22  removed for illustration purposes. Base  24  supports a grill  26 . Grill  26  may be used to support food for cooking, or vessels (not shown) containing food for cooking. The particular configuration of the grill base and lid may be modified significantly without materially affecting the operation of the temperature control apparatus. The grill  26  may even be eliminated if suitable means, such as a container (not shown), are employed to support food to be cooked. 
     Barbeque  20  may also include a console  28  which may be mounted about base  24 . Console  28  may be used to support one or more control knobs  30 , for manual control of associated valves, and part of a temperature control apparatus  32 . It is not necessary that temperature control apparatus  32  be integrally mounted to barbeque  20  via console  28 , or to any other feature of the barbeque. The temperature control apparatus  32  may simply be placed upon any suitable part of barbeque  20  and connected to barbeque  20  as described herein. Hence, temperature control apparatus  32  may be used to modify existing barbeques to provide temperature control as described herein. Alternatively, the temperature control apparatus may be integrated with a purpose built barbeque such as barbeque  20 . 
       FIG. 3  provides a schematic overview of the temperature control apparatus  32 . Many of the components described herein may be substituted by suitable components that are functionally similar. Temperature control apparatus  32  may include an input device  34 . Input device  34  may be a touch sensitive LCD screen (as illustrated), but may alternatively include some other suitable input device, such as a keypad or dial(s). 
     Temperature control apparatus  32  also includes a microprocessor  36 . Microprocessor  36  may be electrically connected to input device  34  for receiving input from a user. Microprocessor  36  is also operatively connected to at least one valve  38 . Valve  38  may be any type of electrically or mechanically controlled valve suitable for changing the flow of a gas. In the present embodiment, valve  38  is an electrically controlled valve. For example, valve  38  may be a latching or latch valve. A latch valve having at least two settings, being open and closed or high and low-flow, may be used either in place of or in addition to, another latch valve or a different type of valve such as a solenoid valve. It is preferable that a latch valve having a high and low-flow setting be used, as will be explained below. The latch valve advantageously requires power to change from one setting (e.g., high) to another (e.g., low), but does not require power to maintain any particular setting. This may advantageously reduce the amount of power required for the temperature control apparatus  32 . This characteristic may be particularly useful if the temperature control apparatus is powered by battery (not shown) or other portable or limited power supply. If power supply is lost or runs out, then a capacitor (not shown) may be included in temperature control apparatus  32  to enable the latch valve to be switched one (or more) times in or to put it in a desired flow state. For example, if power is lost when the latch valve is in a low flow state, the capacitor may be used to switch it to a high flow state so that barbeque  20  may be then used as a conventional barbeque. 
     Alternative valves such as solenoid valve  40 , as shown in  FIGS. 4A and 4B , may be used. Any suitable solenoid valve may also be used, and not just the valve illustrated in  FIGS. 4A and 4B .  FIG. 4A  shows solenoid valve in a closed position.  FIG. 4B  shows the solenoid valve in an open position. Valve  40  may have an opening  41  to encourage a low flow rate when the valve is “closed”. In an embodiment, solenoid valve  40  is switchable between at least a low-flow rate and a high-flow rate. A solenoid valve may be less suitable for uses where power is at a premium because a solenoid valve typically requires power to maintain the valve in at least one of its flow states. This may cause a draw on power, such as battery power. However, if the solenoid valve requires power to enter a low flow rate, then when power is lost, it will automatically revert to a high flow rate, enabling barbeque  20  to be used as a conventional barbeque, without the need for additional power or a capacitor. Valves such as  38  and  40  may alternatively include two valve mechanisms within a single unit, which may provide a more cost effective and/or compact arrangement when more than one valve is employed. 
     Referring again to  FIG. 3 , microprocessor  36  may be operatively connected to a thermocouple, such as thermocouple  42 . Additional thermocouples may be used, as needed. For example, if temperature control apparatus  32  is used to control the temperature of more than one barbeque, or more than one area or zone within a given barbeque, then multiple thermocouples may be used. Additionally, multiple thermocouples may be used to obtain a more accurate reading within a single barbeque enclosure. In one embodiment just one valve may be used to control temperature in a single barbeque enclosure or zone. 
     In the embodiment described herein, a second thermocouple  44  is employed so that temperature control apparatus  32  may be used to control the temperature within two different zones of barbeque  20  (this is described in further detail below). Optionally, an additional thermocouple, such as meat probe  46  may be connected to microprocessor  36  to permit the monitoring of the temperature of a food, such as meat being cooked within barbeque  20 . 
     Temperature control apparatus  32  may receive power from a power supply  48 . Power supply  48  preferably provides 12 volts AC. Temperature control apparatus  32  may also be configured to run on some other suitable voltage, including DC current, provided that suitable circuitry is included with temperature control apparatus  32  to accept such power. Using DC power may permit a battery or other portable form of power to be used. Typically, a 120 volt AC power supply is used and is then converted by a transformer to 12 volt AC power. 
     Microprocessor  36  may accept other inputs such as from a tank level sensor  50 . Tank level sensor  50  provides a signal to microprocessor  36  to indicate the level of a connected fuel supply, which may be used to calculate the time remaining before additional fuel is needed either at the current fuel usage rate, an average fuel usage rate, or some other appropriate measure. This may done by monitoring the rate of change over time and predicting (extrapolating) the time when the tank will be out of fuel. If another gas source is used, for example from a natural gas line, then the tank sensor functionality may be removed or eliminated. 
     The various connections between the components of the temperature control apparatus  32  may be wired or wireless, and may include standard connectors, such as 2.5 millimeter audio style connectors, or may be hard-wired or use some other connection, as desired. 
     Input device  34  may have any of a number of suitable configurations as noted. At its simplest, input device  34  may be a dial, switch or lever that may be moved to select a higher or lower desired temperature for the barbeque  20 . In the illustrated embodiment, input device  34  includes an LCD screen  52  that may be backlit (or may have a sensor or timer to limit or eliminate the amount of back light in order to conserve power, if needed). LCD screen  52  may be touch sensitive, or may be activated using some other input device such as a keypad, a keyboard, a light pen, a mouse, or some other device. The particular layout and style of the graphics for the interface of LCD screen  52  may be configured as needed. No particular layout is required. Aside from the functionality to input a set-point temperature, all other functionality is optional. However, some configurations, such as those described herein, may facilitate inputs to be made and readings to be displayed. 
     The temperature control apparatus  32  may be activated by pressing the on/off button  53  of the LCD screen  52  (when temperature control apparatus  32  is not activated, barbeque  20  may operate as a conventional barbeque). Once activated, a desired temperature may be set by pressing the temperature area  54  of the LCD screen  52 . A set-point temperature may then be entered using up and down arrows  56  and  58  to increase or decrease the desired target temperature. The barbeque  20  may be configured to achieve a wide range of temperatures. For example, the barbeque  20  may be configured to achieve temperatures between 40° C. and 200° C., or 35° C. to 300° C., or 50° C. to 350° C., or to any suitable combination of temperature ranges. The barbeque  20  may also be purpose built for a very narrow temperature range such as between 200 and 300° C. The temperature control apparatus  32  may be configured to achieve any range of temperatures depending on the barbeque  20  configuration. 
     Once a desired temperature is set, microprocessor  36  compares a signal received from thermocouple  32 . The signal indicates the temperature in the vicinity of thermocouple  42 . If the temperature conveyed by thermocouple  42  is within a given range of the set-point temperature, then nothing is done by microprocessor  36 . The range within which the temperature conveyed by thermocouple  42  may differ from the desired set-point may be as low as a fraction (for example, 0.1 of a degree) or as large as one or more degrees, including plus or minus 5° or 10° (Celsius or Fahrenheit). Improved accuracy may be obtained by reducing the range by which the temperature conveyed by thermocouple  42  may differ from the desired temperature set via input device  34 . 
     The range of variation relative to the desired temperature may have a first or lower threshold value, and a second or upper threshold value. While the difference between the lower and upper threshold values may be small, in order to more closely achieve the desired temperature, a small difference in these values may cause the valves, and possibly other components to operate more frequently. This frequent operation may reduce the effective lifetime of such components. Such frequent use may also increase the power consumption, which may be undesirable if there is a limited or restricted power supply. While a greater difference between upper and lower threshold values may produce greater variation in the actual temperature of the barbeque  20 , less energy may be used and a longer life may be obtained from at least some of the components of barbeque  20 . 
     For example, a lower/upper difference of 10° F. (i.e., plus or minus 5° F. about the desired temperature) may provide suitable results. Alternatively, ranges as small as 1° F. or as large as 50° F., or larger depending on the cooking needs. The upper and lower limits for the range may be static relative to the temperature set-point. For example, they may be set to always be within 5° F. of the desired temperature. Alternatively, the upper and lower set-points may vary depending of the temperature set-point. For example, the upper and lower limits may be within 10° F. of the desired temperature at a lower temperature such as 40° F., whereas they may define a smaller range, for example, plus or minus 3° F., relative to a higher set-point temperature, such as 200° F. 
     This dynamic variation of upper and lower set-points may be used advantageously to take advantage of the thermal dynamic characteristics of the barbeque assembly  20 . 
     When microprocessor  36  receives a signal from thermocouple  42  indicating a temperature greater than (or optionally, equal to) an upper limit value, microprocessor  36  sends a signal to valve  38  to cause it to enter a low or no-flow state. 
     In the present embodiment, valve  38  enters a low-flow state. Microprocessor  36  compares temperature information from thermocouple  42  and compares it with the upper and lower limits as frequently as once per second, or fraction of a second, or as infrequently as every several minutes. The typical range for this comparison may be between 0 to 30 seconds. This provides sufficient time for a change in the temperature of the barbeque  20  to stabilize after a change in the state of valve  38 . 
     When microprocessor  36  determines that the temperature conveyed by thermocouple  42  has fallen below a lower threshold (or alternatively, is equal to a lower threshold), then it may signal valve  38  to turn on or to switch to a high-flow state. This may cause the temperature within barbeque  20  to increase above the lower threshold. Microprocessor  36  may continue to receive signals from thermocouple  42 , and to cycle valve  38  between high and low (or, in some embodiments, off) states in order to achieve a desired temperature within barbeque  20 . For example, when microprocessor  36  compares the temperature of thermocouple  42  against the lower and upper temperature thresholds every 5 seconds, and the upper and lower threshold values are separated by a range of 10° F., the temperature within barbeque  20 , having a closed lid  22 , has been found to be maintainable within as little as one or two degrees Fahrenheit of the desired temperature. 
     A safety feature may be included in the temperature control apparatus  32 . Microprocessor  36  may include memory (not shown), if needed, for example, for storing historical temperature data. In an embodiment, at least the previous reading from thermocouple  42  may be stored for comparison with a subsequent reading. If a difference between the previous and subsequent readings relative to the time between readings is sufficiently great or sufficiently small, then an alarm may sound. Furthermore, if the differences in the previous and subsequent temperatures is great enough, microprocessor  36  may signal valve  38  to change into an off or low-flow state. This may occur, for example, if there is a flare-up or fire within the barbeque  20 , causing a rapid increase in the temperature therein. Alternatively, if there is a rapid decrease in temperature, then the flame may have gone out and the flow of fuel may need to be shut off or reduced. In either case, an alarm may sound to alert the user to an error condition. 
     As noted, more than one thermocouple may be employed within a single barbeque assembly  20 . In such case, microprocessor  36  may take an average or weighted reading of the various thermocouples to determine the temperature of the barbeque  20 . Alternatively, barbeque  20  may be divided into two or more zones (or additional barbeques may be connected to temperature control apparatus  32 ), with at least one thermocouple being placed in each zone or barbeque. 
     When temperature control apparatus  32  is connected to thermocouples in two or more thermally separated zones of barbeque  22 , different temperature states may be achieved within barbeque  20 . For example, a desired temperature may be set for thermocouple  44  in a manner similar to that set for thermocouple  42 . Thermocouple  44  may be set at a temperature the same as, higher than, or lower than the zone in which thermocouple  42  is placed (for example, zones  1  and  2  are illustrated in  FIG. 3 ). Zones  1  and  2  may be thermally separated by a physical divider (as described in further detail below) or they may simply represent different areas within barbeque  20 . If zones  1  and  2  are not physically divided, then achieving significantly different temperatures between thermocouple  42  and thermocouple  44  may be more difficult. Nevertheless, barbeque  20  may include a generally warmer area and a generally less warm area. When more than one zone or barbeque is to be controlled using the temperature control apparatus  32 , then at least one additional (or integrated) valve assembly  60  may be used for each zone controlled by temperature control apparatus  32 . Microprocessor  36  may then be configured to independently control each respective valve, such as  38  and  60 , in response to temperatures encoded by thermocouples  32  and  44 . 
     Temperature control apparatus  32  may also operate in conjunction with a thermocouple  46 . Input device  34  may be used to enter a type of meat (such as, pork, beef, chicken, or lamb) and a desired doneness (e.g., well done, medium, medium-rare, or rare). Microprocessor  36  may then control the temperature of barbeque  20  employing one or both thermocouples  42 ,  44 , to achieve a pre-determined temperature in order to cook the meat to a desirable extent. 
     Temperature control apparatus  32  may additionally be connected to a tank level sensor  50  for determining the amount of fuel left in a connected fuel reservoir, such as a liquid propane tank  66 . An icon, such as icon  67  may graphically or numerically illustrate the amount of fuel remaining. Microprocessor  36  may be connected to a tank level sensor (described below), and may be configured to shut off valves such as valve  38  when the tank is low or empty. 
     Tank  66  may be provided with a regulator  68  for ensuring that the pressure of the fuel provided to barbeque  20  is at a constant pressure, regardless of the flow setting of the valves (such as valve  38 ). Hence, even though valve  38  may be in a low-flow state, the pressure of the fuel transmitted therethrough to barbeque  20  may be at generally the same pressure as the fuel transmitted when valve  38  is in a high-flow state. The valves, such as valve  38  and valve  60 , do not include a regulator or have a regulator associated therewith. This may be advantageous because it may reduce the chance that a “flame-out” occurs within barbeque  20  due to insufficient fuel pressure. It may also reduce the cost of valves  38  and  60 . Since fuel flow is not regulated by pressure, the valves need not include a regulator. A fuel pressure of about 11 inches water column (WC) may be employed for propane and about 7 inches WC for natural gas. This may vary depending on requirements and government or other regulations which may vary by jurisdiction. 
       FIGS. 5A to 5P  illustrate an example of a configuration for a LCD screen  52  of the temperature control apparatus  32 . As noted, the particular layout, font, figures, and functionality included may be varied, added to, or removed. For example, functionality relating to a meat probe or tank level sensor may be eliminated or removed to reduce cost or for some other reason. At a minimum, means for inputting a desired temperature set-point may be included, unless the system is designed to always maintain the same temperature, such as for a commercial application. Features highlighted for LCD display  52  are shown darkened in the figures for ease of illustration. The various features may be darkened or not in an embodiment. Different colours and lighting, including back-lighting, may be employed to improve readability and usability. 
       FIG. 5A  shows an on/off button graphic  53 . Pressing screen  52  about this graphic, causes the temperature control apparatus  32  to switch off and on, as desired. As noted, when temperature control apparatus is in an “off” state, barbeque  20  may operate as a conventional barbeque. Alternatively, barbeque  20  may be configured without one or more, or all of knobs  30 . In this configuration, temperature control apparatus  32  may control all fuel flow to barbeque  20 . Valves  38  may be configured to include an “off” setting, or fuel flow may be switched off, for example manually, at tank  66 , or at some other fuel source that is connected to barbeque  20 . In this alternative configuration, barbeque  20  may be difficult to achieve a desired temperature without turning temperature control apparatus  32  on. 
       FIG. 5B  illustrates a countdown timer that may be included. The countdown timer may be set in a manner similar to that described for the temperature setting. The countdown timer may be used to turn off or change fuel flow after a certain period of time. Alternatively, it may be used as a simple timer. This feature may be activated by pressing the hour glass icon  70  and adjusting the desired time by pressing the arrow keys  56  and  58 . 
       FIG. 5C  illustrates icons of display  52  that may be used to set a temperature, as described above. If temperature control apparatus  32  is configured to control two zones (it may be used for just one zone or barbeque), then zone control button  54  may be pressed, followed by increase/decrease arrows  56  and  58  in order to enter a desired temperature set-point. A similar operation may be followed for a second zone by pressing second zone button  72 . If both zones are to have the same temperature set-point, then button  74  may be pressed and both zones desired temperatures will be set at the same time by pressing increase/decrease arrows  56  and  58 . 
       FIG. 5D  includes a food-type entry input  76 . This may be used to toggle or scroll through different meat types, and to enter a desired doneness for the food as illustrated at  62 . Microprocessor  36  may be encoded with any variety of food types and characteristics to be entered via display  52 . 
       FIG. 5E  illustrates setting of a clock feature  78 . Microprocessor  36  may be configured to maintain display of clock  78  even when display  52  has been switched off. Clock  78  may be set by pressing in the area of clock  78  and the up or down arrow at the same time in order to increment or decrement the clock setting. It should be noted that all functions are preferably configured to require simple single button sequential pressing to avoid the need for a separate clock icon. Both the clock and arrow areas of display  52  are pressed at the same time for setting. However, an alternative configuration could be employed so that a clock icon is pressed and the arrow keys subsequently pressed in order to set the clock. 
       FIG. 5F  illustrates employing the increase icon  56 , and  FIG. 5G  illustrates using the decrease icon  58 . These icons are used to increase and decrease values associated with the various functions of the temperature control apparatus  32 . 
       FIG. 5H  illustrates a preheat function that may be encoded into microprocessor  36 . A preheat button  80  of display  56  may be pressed. This causes microprocessor  36  to activate valve  38  to a high setting so that zone  1  (and any other zone activated, in which case additional valves are activated). Valve  38  is activated to a high flow rate so that the associated zone in barbeque  20  quickly achieves a predetermined preheat temperature. In the present example, a preheat temperature of 400° F. is pre-programmed in microprocessor  36  as the preheat temperature. Any other temperature may be pre-programmed as a preheat temperature. Alternatively, temperature control apparatus  32  may be configured, including screen  52 , to have a manually settable preheat temperature. Once the preheat temperature is reached, the temperature control apparatus may beep one or more times, at intervals if desired. For example, the temperature control apparatus  32  may beep for a period of 5 seconds every minute for 5 minutes. 
       FIG. 5M  illustrates a food-specific function that may be coded into microprocessor  36  and implemented into display  52 . A food icon  76  may be used in conjunction with a probe such as a thermocouple meat probe  46  (see  FIG. 3 ). When the meat probe reaches a desired temperature, the temperature control apparatus  32  may issue a beep. When the probe reaches a temperature over the set-point (for example, 5° over the set-point, a continuous or repeated beep may issue). A sample table of goal temperatures for various food items follows. These values may be pre-programmed into microprocessor  36 . Any other of a wide range of values may be pre-coded for use with different types of foods or cooking scenarios. Optionally, temperature control apparatus  32  may be configured to enable coding of values by a user. In such case, a random access memory, such as a stable flash memory may be employed in the temperature control apparatus. 
     
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
                   
               
               
                   
                 Well-Done 
                 Medium 
                 Medium-Rare 
                 Rare 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Beef 
                 170° F. 
                 160° F. 
                 145° F. 
                 135° F. 
               
               
                 Lamb 
                 170° F. 
                 160° F. 
                 145° F. 
                 135° F. 
               
               
                 Veal 
                 170° F. 
                 160° F. 
                 145° F. 
                 135° F. 
               
               
                 Chicken 
                 180° F. 
               
               
                 Turkey 
                 180° F. 
               
               
                 Pork 
                 170° F. 
               
               
                 Fish 
                 160° F. 
               
               
                 Hamburger 
                 160° F. 
               
               
                   
               
             
          
         
       
     
       FIG. 5K  illustrates entering a food type by repeatedly pressing the food icon  76 .  FIG. 5K  at the right side thereof illustrates the various food types that will be displayed as food-type icon  76  is pressed. 
       FIG. 5L  illustrates display  52  after it has been set to cook beef medium-rare.  FIG. 5L  illustrates that the probe temperature is below the set temperature of 145° F. 
       FIG. 5I  further illustrates temperature control setting. In the present example, temperature may be set in five degree increments. However, the temperature control apparatus  32  may be configured to enable other increments including fractions of a degree. The temperature control apparatus  32  may be configured to sound an alarm or to flash a light once a target temperature has been reached. 
       FIG. 5J  illustrates a condition when the target temperature cannot be reached after a certain period of time. The period of time may be predetermined by encoding microprocessor  36  accordingly. For example, if a set-point temperature such as 145 degrees (the set point display shown as reference  64  in  FIG. 3 ) is not achieved within 10 minutes, then an alarm, whether visual, auditory or other sensory indicator, may be activated to indicate to a user that the target temperature cannot be achieved, either because the temperature is too high or too low. The goal temperature may then be reset accordingly or the barbeque  20  may be examined to determine whether there is a fault. 
       FIG. 5N  illustrates that up button  56  may be used in conjunction with automatic temperature control button  82  to toggle between different temperature units, such as Celsius and Fahrenheit. 
       FIG. 5O  illustrates the fuel tank level icon  67  described above. Icon  67  may be configured to illustrate a progressively empty fuel vessel as illustrated in  FIG. 5P . Processor  36  may be programmed to query the tank level sensor  50  at a predetermined interval such as 30 seconds. Tank level icon  67  may then include one or more bars corresponding to a predetermined level. Depending on the tank level value returned by tank level sensor  50 , a given number of bars may be activated in icon  67  to illustrate graphically the amount of fuel remaining. Alternatively, a number corresponding to the level of the fuel tank may be illustrated. An alarm may be activated when the fuel tank  66  reaches a predetermined level, such as 10%. 
       FIG. 6  is an isolated view of barbecue base  24  and console  28 .  FIG. 6  illustrates that the barbecue  20  may include an auxiliary burner (not shown) connected by conduit  84 . The present embodiment may include three burners  86 ,  88  and  90 . Barbecue  20  may be configured to have any number of burners, including just one burner, or multiple burners. If just one burner, such as burner  86 , or  88 , is employed, then temperature control apparatus  32  will typically include just one valve assembly, such as valve assembly  38 . Each burner  86 ,  88  and  90  may define separate heating zones within barbecue  20 . In such case, barbecue  20  may be thermally separated into three different zones. In the embodiment shown in  FIG. 6 , barbecue  20  includes just two heating zones. Burners  86  and  88  may be associated with heating zone  1  and burner  90  may be associated with heating zone  2 . Heating zones  1  and  2  may be separated by a divider (discussed below) that is resistant to thermal transmission. This may ensure that zones  1  and  2  may be controlled independently to have different temperatures, or they may be controlled relatively independently to have the same temperature. Burners  86 ,  88  and  90  may have different configurations, or the same configuration, and they may include the burner types illustrated, or any other burner known in the art, including those conventionally used for gas fuelled appliances, such as barbecues. 
       FIG. 7  illustrates an isolated rear view of console  28  and associated components of barbecue  20 , including components of the temperature control apparatus  32 .  FIG. 7  should be viewed in conjunction with  FIG. 6 . When temperature control apparatus  32  is off or not activated, control knobs  30 ,  92  and  94 , each associated with a respective burner  86 ,  88  and  90 , may be used to control in a conventional manner the flow of a combustible fuel in a conventional manner. Each control knob includes an associated valve. Any suitable control knob and valve combination may be used, including those well known in the art. Additional control knobs may be included, such as control knobs  96  (e.g., for a rotisserie),  98  and  100 . Control knob  98  may be used to control the flow of fuel to an additional burner or other appliance via conduit  102  which connects to conduit  84  (shown in  FIG. 6 ). 
     Each valve, such as valve  38 , associated with a zone may have a minimum flow rate that is similar to or equal to the sum of the flow rates of the associated controls, such as controls  30  and  92 . For example, if controls  30  and  92  each have a minimum flow rate of 5,000 BTUs, then valve  38  preferably has a minimum flow rate of 10,000 BTUs (i.e., 5,000+5,000). This configuration permits valve  38  to supply a minimum amount of fuel to controls  30  and  92 . If the minimum flow rate of valve  38  is made lower than the sum of the minimum flow rates of the associated control or controls, then it is possible for any associated burner, such as burner  86  or  88  to “flame out” due to an insufficient fuel supply. The minimum flow rate for valve  38  may be in the range of 10,000 BTUs, and the maximum flow rate may be in the range of 25,000 BTUs. Higher and lower values may also be suitable depending on the configuration such as the volume of the barbeque to be heated. 
     Control  30  may be configured to include an off position in which the flow of fuel to burner  86  is inhibited. The off position may be a discreet position. For example, control  30  may click or snap into an off position. Control  30  may also have discreet or continuous high and low positions, permitting high and low rates of fuel flow to burner  86 . In an embodiment, control  30  must be pushed when it is in an off position before it may be turned to a high or low position. Once in a high, low, or intermediate position, it may be released. Control  30  may then be rotated between high and low positions, without pushing it, in order to set a fuel flow rate that is high, low or at some intermediate position. To return to an off position, control  30  may be pressed and turned to the off position. The other valves  92 ,  94 ,  96 ,  98  and  100  may be similarly configured. 
     In the illustrated embodiment, the controls, such as controls  30 ,  92  and  94 , that are associated with the temperature control apparatus  32 , may also be used at the time that the temperature control apparatus  32  is activated. For example, when control  30  is put to an intermediate flow position, temperature control apparatus  32  may operate valve  38  to cycle gas flow between the low flow rate of valve  38  and the intermediate flow rate as set by control  30 . If control  30  is placed to a high flow rate setting, then the temperature control apparatus  32  may operate to achieve and maintain temperatures within a broader range. When temperature control apparatus  32  is used, all associated valves ( 30 ,  92  and  94 ) will typically be placed by a user to a high flow position to provide the temperature control apparatus  32  with the largest possible range of operation. 
     Temperature control apparatus  32  may also operate if all control knobs, such as control  30  are eliminated. In such case, flow of the fuel may be turned off as a shut-off valve  106  of regulator  68 . All control knobs may be conveniently connected via a manifold  108 . When the temperature of more than 1 zone is to be controlled, then the controls and associated burners for a given zone may be connected via separate manifolds. In the present example, a second manifold  110  may be included for zone  2 . This can be seen in  FIG. 7 . Manifold  108  may connect burners  86  and  88 , and associated controls  30  and  92 . Manifold  108  may also be connected with valve  38 . In this way, the temperature control apparatus  32  may separately control the burners in zone  1  via valve  38 , and the burners in zone  2  via valve  60   
     Temperature sensors such as thermocouples  42  and  44  may be located within each of zones  1  and  2 . The thermocouples may be mounted to a side of base  24 , or any other location. Thermocouples  42  and  44  are preferably placed to avoid contact with any drippings or splatter from food cooked within barbecue  20 . 
     Barbecue assembly  20  may additionally include an ignitor for igniting fuel communicated to the burners, such as burner  86 . Alternatively, a match or other suitable means may be used to ignite the burners. 
       FIG. 8  shows barbecue  20  without closure members  112  (as shown in  FIG. 1 ).  FIG. 8  illustrates a possible placement of tank sensor  50 . Tank sensor  50  is illustrated in greater detail in  FIGS. 9A to 9D . Tank sensor  50  may be used to determine the fuel level in a tank  66  associated therewith. Tank sensor  50  may be connected to temperature control apparatus  32  via a connector  114 . A sensor such as that manufactured by Sensotech Inc. of 1250 Rene-Levesque Boulevard, Montrol, Quebec may be suitable, or as disclosed in Patent Corporation Treaty application no. PCT/CA2005/001935 and U.S. patent application Ser. No. 11/029,415 and other applications claiming sensor devices and which are owned Sensotech Inc., the disclosures of which are incorporated herein by reference. 
       FIGS. 10 and 10A  illustrate a support for a fuel reservoir such as fuel reservoir  66  (see also  FIG. 12 ). As further illustrated in  FIGS. 11A to 11D , support  116  includes at least 1 protrusion  118  that corresponds to a lower portion  120  (see  FIG. 12 ) of tank  66 . Support  116  may additionally include portions defining a void  122  for receiving a stand  124  of tank  66 . Void  122  may be configured as a continuous slot (not shown) for receiving an edge of stand  124 . 
     Tank support  116  may additionally include a rebate  126  for receiving sensor  50 . Rebate  126  may be configured to conform to a perimeter of sensor  50  so that sensor  50  engages edges defining rebate  50  in a snap fit. Alternatively, rebate  126  may be configured for a friction fit, or may simply retain sensor  50  by gravity fit. 
     Tank support  116  may be formed integrally with a shelf  128  of barbecue assembly  20 . This may make it difficult to install, remove, and replace tank  66 . Accordingly, tank support  116  may be configured as a separate member movable relative to shelf  128 . Tank support  116  may be mounted to two shelf  128  on rails, sliders or some other suitable arrangement. As illustrated in  FIG. 10A , tank support  116  may be configured to slidably engage shelf  128 . A stabilizer, such as rail  130 , may be included to provide additional support and guidance to tank support  116  when it is moved relative to shelf  128 . 
     Tank support  116  may also include a guide in the form of a rib for engaging a complimentary feature of shelf  128 . Rib  132  may be located upon either side of tank support  116  to permit generally linear movement of tank support  116  relative to shelf  128 . Rib  130  and rib  132  serve to discourage displacement or tipping of tank support  116  relative to shelf  128  when shelf  128  is moved for removal or replacement of tank  66 . 
     Tank support  116  may additionally include a retainer or a lock such as latch  134 . Latch  134  may be movable within tank support  116  so that it engages shelf  128  or a complimentary feature in shelf  128 . As shown in  FIG. 12 , latch  134  extends generally perpendicular to a plane of movement of tank support  116  so that it may engage a corresponding feature (not shown) of shelf  128 . Latch  134  discourages movement of tank support  116  relative to shelf  128  when tank support  116  is in engagement with shelf  128 , and tank  66  is positioned for use. This arrangement may further discourage movement of tank  66  when barbecue  20  is operated. 
       FIG. 12  is a cross sectional view providing further illustration of both tank support  116  and the positioning of tank level sensor  50 . Tank level sensor  50  preferably contacts tank  66  sufficiently that it may communicate and receive signals therewith in order to determine the amount of fuel within tank  66 . 
       FIG. 13  illustrates barbecue  20  configured to have multiple zones, described above. By differentially controlling two or more of burners  86 ,  88  and  90  (see for example,  FIG. 7 ), barbecue  20  may be provided with thermally differentiated zones therein. As shown in  FIGS. 13A to 13D , and in an isolated view shown in  FIG. 14 , a divider such as divider  136  may be included with barbecue  20  to encourage or facilitate thermal differentiation between the various zones. In the example shown in  FIG. 13 , thermally differentiated zones  1  and  2  are illustrated. Even without divider  136 , thermally differentiated zones may exist, for example, if a high flow rate fuel is provided to one burner, such as  86 , and a low flow rate of fuel is provided, for example, to burner  90 , then zone  1  may be generally warmer than zone  2 . However, when lid  22  is closed, heat from the warmer zone will tend to transfer to the less warm zone, thus inhibiting differentiated cooking between zone  1  and zone  2 . 
     Employing a divider, such as divider  136 , in order to thermally separate two or more zones within barbecue  20  may permit thermally differentiated cooking. For example, a steak or other meat requiring a higher cooking temperature may be included in zone  1 , whereas vegetables requiring a lower temperature may be included in zone  2 . This may permit the cooking of both meat and vegetables at the same time, on the same barbecue, but at different temperatures. If a sufficient air seal is achieved between zones  1  and  2  when lid  22  is closed and divider  136  is in place, then the effect of flavours and other aromas produced by the cooking of food in one zone may be reduced in the other zone, thus preserving flavours of items cooked. However, an air seal is not required for divider  136  to operate. 
     Divider  136  may be made of a material that resists the transfer of thermal energy, such as a ceramic. However, thermally conductive materials, including metals, may be used because such materials will also serve to inhibit thermal transfer between zones  1  and  2 . A combination of materials such as insulation sandwiched between sheets of metal, may also be employed. 
     Divider  136  may conform to an inside perimeter of lid  22  and base  24  when lid  22  is closed. In such configuration, divider  36  may divide or bifurcate the volume enclosed by base  24  and closed lid  22 . Divider  136  may divide such volume into two equal volumes, or unequal volumes depending on cooking needs, such as the grill  26  area required, and the placement of burners, such as burners  86 ,  88  and  90 . 
       FIG. 13  illustrates divider  136  in a plane generally perpendicular to grill  26  and generally perpendicular to a plane of the front of grill  20 . Divider  136  may alternatively be placed in any other orientation that serves to thermally separate the internal volume of grill  20 . Furthermore, multiple dividers  136  may be employed, for example, to thermally separate each of burners  86 ,  88  and  90 . In the present embodiment, divider  136  may limit the effect of different temperatures in zones  1  and  2  on each other. For example, divider  136  may limit the effect of a temperature in zone  1  on zone  2  by not more than plus or minus 10 degrees Fahrenheit. In a further example, if the temperature of zone  1  is 300 degrees Fahrenheit, and a desired temperature of zone  2  is 200 degrees Fahrenheit, then zone  1  will generally, at most, raise the temperature of zone  2  to 210 degrees Fahrenheit with divider  136  in place. As noted below, the extent of this effect may depend on the material used for divider  136  and the extent to which divider  136  seals zone  1  from zone  2 . 
     While divider  136  preferably conforms to an internal perimeter of combined lid  22  and base  24 , it needs not completely conform to such internal perimeter. With reduced conforming to such internal perimeter, divider  136  may be less thermally inhibiting. Nevertheless, even a limited amount of thermal resistance by divider  136  to the transfer of heat between zones  1  and  2  may provide a suitable differentiation in cooking temperature in each of zones  1  and  2 . 
     Divider  136  may be cut, stamped, moulded or otherwise formed as a single sheet, or as multiple sheets or pieces connected together. As noted, divider  136  may be made of a metal, a plastic, or some other substance that resists burning. 
     In an embodiment, divider  136  may be a single, generally continuous, generally planar sheet. Grill  26  may be formed of two separated grill parts (not shown). Divider  136  may then be placed between each grill part. The grill parts may serve to support divider  136 . 
     Divider  136  may alternatively be provided with one or more rebates for avoiding features of grill  20  that may inhibit placement of divider  136 . For example, divider  136  may be provided with one or more grill rebates  138 . Rebates  138  may be dimensioned and located to receive a portion of grill  26  that may inhibit placement of divider  136  as shown in  FIG. 13A . Rebates  138  may each receive one or more of the steel members that form grill  26 . The positioning, number, and orientation of rebates, such as rebates  136 , may be determined by the particular configuration of a given barbecue. For example, a barbecue may additionally include a warming rack  140 . Accordingly, divider  136  may include a warming rack rebate  142  to accommodate warming rack  140 , as seen in  FIG. 13A . Warming rack rebate  142  may be configured to closely correspond to a portion of a perimeter of warming rack  140 . As mentioned, rebates such as rebate  142  may generally correspond to a feature such as warming rack  140 , and may permit a limited amount of thermal transfer, including air, to pass. The rebates, such as rebate  142 , may be made large enough for easy passage of obstructions, such as warming rack  140 , therein. If a given barbecue configuration does not include obstructions inhibiting the placement of divider  136 , then divider  136  need not be provided with any rebates. 
     Rebates  138  in turn define tongues  144  (additional tongues may be defined such as tongues  146  and  148 ). The tongues together serve to inhibit movement of energy, air, fumes and other matter between the zones. 
     Divider  136  may include a stabilizer, attachment, or other feature to maintain its intended placement, and to permit divider  136  to resist movement when barbecue  20  is used. For example, a stabilizer  150  may be included at one or both ends of divider  136 . Stabilizer  150  may be configured to abut a corresponding feature of grill  26 . Stabilizer  150  may alternatively be located at an intermediate portion of divider  136 . For example, stabilizer  150  may be placed adjacent to any part of rebate  142  to provide stabilization of divider  136  against warming rack  142 . In the illustrated embodiment, 2 stabilizers  150  are provided to lie upon grill  26  in a direction transverse to a plane of divider  136 . In this configuration, stabilizer  150  may inhibit lateral movement of divider  136 . Stabilizer  150  is illustrated as being stick-like. Alternatively, stabilizer  150  may be provided at an angle less than 90 degrees relative to divider  146 , in order to still impart stability to divider  136 . Other protrusions from divider  136 , may also be included so long as they provide a measure of support to divider  136  in order inhibit its movement when installed in barbecue  20 . Alternatively, or additionally, divider  136  may be made to have a thickness approximating the spacing of grill  26 . In this way, a friction fit may be formed between divider  136  and grill  26  when it is inserted therein. 
     Divider  136  may alternatively be permanently or temporarily attached to one or both of grill  26  and base  24 . For example, divider  136  may be welded, caulked, screwed, bolted, or otherwise mounted to grill  26  or base  24 , or both. Divider  136  may alternatively be attached to an inside surface of lid  22  so that it is moved in and out of place by opening and closing lid  22 . In such configuration, the shapes of one or more of rebates  138  and  142  may need to be changed to accommodate this movement. 
     Support for divider  136  may alternatively, or additionally, be provided by a feature of base  24  (not shown). For example base  24  may include a receptacle or groove for receiving an edge of divider  136  in order to maintain its position. Such groove preferably has a width corresponding to, or marginally less than, a width of divider  136  to provide a friction fit when divider  136  is placed therein. 
     Divider  136  may alternatively constructed of two or more separate pieces. For example, a divider portion (not shown) may be installed below grill  26 . A second complimentary portion may then be installed above grill  26 . Such configuration could serve to reduce the need for any rebates, such as rebates  138 . This in turn could reduce the extent to which thermal energy, air, and other matter can pass between zone  1  and zone  2 . In a further alternative, divider  136  may be installed through a slot provided in base  24  (not shown). In this configuration, divider  136  may be installed in a generally opposite direction to the manner illustrated in  FIG. 13 . A retainer or other feature may be provided to prevent divider  136  from falling out of the slot and base  24 . A similar feature could also be provided using a slot in lid  22 . 
       FIG. 15  illustrates barbecue  22  and an internal storage system. The internal storage system may include a container  152  slidably mounted to shelf  128 , for example via conventional telescoping rails  154 , and a nestable container  156 . Container  152  may be made of any suitable material, such as a plastic, and may be dimensioned to occupy a suitable portion of a volume defined by barbecue shelf  128 , barbecue walls  158 , doors  112  (see  FIG. 1 ) and back (not shown). Storage  152  may have generally rectilinear dimensions, but may also be rounded or some other shape, as required. Container  152  may be slideably mounted to shelf  128  by providing a complimentary indent (not shown) in shelf  128  for receiving the bottom of container  152 . Alternatively, container  152  may be mounted to a movable shelf (not shown). Container  152  may be used to store grill  26 , or parts of grill  26 , or other components of barbecue  20  or tools or appliances used in conjunction with barbecue. Container  152  may include a grip or handle  159  attached or integrally formed in some convenient location of container  152 , such as a top edge thereof. 
     The storage system may also be provided with an insert, such as insert container  156 . Insert container  156  preferably includes a lip  160  for supporting insert  156  upon edges  162  of container  152 . Container  156  may additionally include a grip or handle such as an opening  164 . Any other suitable handle may alternatively or additionally be applied. 
       FIG. 16A  to  FIG. 16D  illustrate various views of the storage system. 
       FIG. 17, 17A  and  FIGS. 18A to 18A  illustrate a receptacle  166  for receiving grease, fat or other matter that may drip, fall or otherwise reside within base  24 . An opening (not shown) within base  24  may permit the passage of such material into receptacle  166 . Receptacle  166  may be any convenient size and shape to define a volume suitable for receiving an predetermined amount of material, such as fat or grease, that may be caught therein. For example, receptacle  166  may have the following approximate dimensions: about 1 inch deep by about 8 inches wide by about 5 inches long. In the preferred embodiment, receptacle  166  has dimensions of 1.1 inches deep by 7.785 inches wide by 5.315 inches long. 
     Receptacle  166  may be supported by a shelf  16 A. Shelf  16 A may define an opening  170  for receiving receptacle  166 . Opening  170  may be a similar size and shape as receptacle  166 . Receptacle  166  may additionally have one or more protrusions, which may be in the nature of a continuous lip  172  for inhibiting passage of receptacle  166  through opening  170 . Lip  172  may traverse all or a part of a perimeter of receptacle  166 . 
     Shelf  168  may be movable within a slot  174  of barbecue  20 . Other slidable means or other feature permitting movement of receptacle  166  between a position for receiving matter to a position in which receptacle  166  may be removed, may also be employed. Shelf  168  may also be conveniently provided with a grip or catch such as in the nature of a handle  176 . 
       FIGS. 19, 19A and 20A to 20D  illustrate an infrared burner  178  that may be included in addition to burners  86 ,  88  and  90 . Alternatively, infrared burner  178  may be employed alone or in conjunction with any other number of burners or even with additional infrared burners. Control knob  100  may be used to adjust the flow of fuel to infrared burner  178  (or another type of burner such as burner  179 , shown in  FIG. 6 ). Temperature control system  32  may be used to additionally control infrared burner  178 . As seen in  FIG. 7 , control valve  100  is connected to valve  60  of temperature control system  32  (infrared burner  178  is not shown in  FIG. 7  for ease of illustration). Accordingly, temperature control apparatus  32  may be used to control fuel flow to infrared burner  178  to achieve a desired temperature in zone  2  of barbecue  20 . Infrared burner  178  may be placed in any convenient location, including above burners  86 ,  88  and  90  to enable infrared burner  178  to cook food, for example, placed on a rotisserie above grill  26  (not shown). 
     The following focuses on the operation of the programming of temperature control apparatus  32 , identifying aspects of the operation of the programmed software as shown in part in  FIG. 21 . 
     Software of temperature control apparatus  32  may be programmed to include the following functions described below. One or more of the evaluations made by the software may be done in a different order as set out below, or as shown in  FIG. 21 , as appropriate. 
     As illustrated in  FIG. 21 , the operation of the following disclosed aspects of the software may begin at step  200 , for example, by a user turning on temperature control apparatus  32 . At step  202 , the software evaluates whether a condition exists in which an alarm should be activated due to barbeque  20  being too hot, or if the temperature measured within barbeque  20  increases or decreases in temperature at higher than a predetermined rate. 
     Step  202  may also evaluate whether any other safety or alarm condition exists. If such a condition exists, then the software instructs temperature control apparatus  32  to lower the flow rate of a connected fuel flow control device, such as valve  38 . For example, valve  38  maybe set to a low flow rate following an alarm or error condition. This is done to reduce the amount of fuel provided in the event that something is wrong with the burning of fuel. If control valve  38  is configured to have an off state, then the software may cause valve  38  to turn off in step  204 . 
     In step  206 , the software evaluates whether barbeque  20  is set for manual operation. For example, temperature control apparatus  32  may include an input for a user to select between manual or automatic operation. Alternatively, if no desired temperature set point is entered, then temperature control apparatus  32  may default to manual operation. In such case, in step  210  valve  38  (or other flow control device) may be set to permit fuel flow, and is preferably set to permit a high flow rate. In this manner, a user may manually restrict fuel flow using one or more of control knobs, such as control knobs  30 . 
     In step  220 , the software assesses whether the measured temperature of barbeque  20  is within a predetermined range of a desired set point. For example, the software may determine whether the measured temperature is with 2° F. (for example, either 2° above or below a desired temperature set point). If the measured temperature is within this range then the software does not change the present flow rate of fuel, whether such flow rate is at a high rate, a low rate, or otherwise. 
     In step  222  the software assesses whether the measured temperature is higher than the temperature range described above. For example, it may evaluate whether the measured temperature is higher than the desired set point temperature plus a set amount, such as 2° F. If the measured temperature is above such total, the software may send an instruction to lower or otherwise restrict the flow rate of fuel (in some embodiments it may instruct fuel flow to be turned off). If the measured temperature is not higher than the predetermined range, fuel flow is maintained in step  226 . 
     Additionally (not shown), a further step of evaluating whether the measured temperature is below the predetermined temperature range may be carried out. If the measured temperature is below such range then the flow of fuel may be increased, for example, by setting valve  38  to a high flow rate. 
     As can be seen from  FIG. 21 , the ultimate result of any step is a return to just after start step  200 . This permits the continuous evaluation of the various states of barbeque  20 . Evaluation may be performed by the software at any interval, for example, evaluation may be done many times per second, or evaluation may be done intermittently, such as every few seconds, every minute, or after a series of minutes. Of course, evaluation may be done at varying intervals, depending on the stage of cooking. For example, at start up, evaluation of the temperature state of barbeque  20  may be done every minute, however, once a temperature set point is approached, then evaluation of various states of barbeque  20  may be done more frequently. For safety, evaluation is preferably done frequently. 
     It is also possible to change the ordering of one or more steps. For example, the assessment of the alarm condition in step  202  may occur after any other step described. It is also possible to evaluate one step more often than other steps. For example, the measured temperature comparison in step  220  may be conducted two or more times for every one time that the manual operation evaluation is conducted in step  206 . Alternatively, the alarm status evaluation of step  202  may be conducted after each and every other step in the flow chart. 
     The foregoing example has been described in the context of controlling temperature within a single area or volume of barbeque  20 . As described, barbeque  20  may have one or more zones that may require different temperature control. In such case, additional zones may be controlled using similar steps as described herein. 
     Further description and examples of the functionality illustrated in  FIG. 21  follow. 
     In an embodiment, if a set point temperature is below a preset minimum value (for example, a predetermined temperature in the range of 110° C. or 225° F.), the barbeque  20  may enter a manual mode where the flow rate may be manually set by the user and the temperature control apparatus  32  will not operate to control the valve  38 . Otherwise, if a mode of the temperature control apparatus  32  is set by a user to “preheat”, a predetermined preheat set point may be used as the target temperature instead of a user inputted desired temperature. Preheat may be pre-determined or coded in temperature control apparatus  32  at 200° C. or 400° F., or some other value for getting barbeque  20  in a state ready for cooking. 
     A user may also set the temperature control apparatus  32  to a keep warm setting. If keep warm is set and the keep warm set point temperature is below the user set point temperature, the keep warm set point will be used as the target temperature by the temperature control apparatus  32 . The keep warm set point may be any suitable temperature that slows or stops the rate of cooking of food placed within barbeque  20 . The temperature may be pre-programmed. The keep warm temperature may also be activated when a timer (such as illustrated in  FIG. 5B ) reaches zero. In response to the timer completing, the set point is reduced to the keep warm set point temperature. 
     In an embodiment, if none of the above conditions is true, the user inputted desired temperature set point may be used as the target temperature. 
     If the measured temperature of barbeque  20  is generally above about a desired target temperature plus a predetermined amount or hysteresis, the temperature control apparatus  32  changes the fuel flow rate to low flow rate. If the measured temperature is below the target temperature minus a predetermined amount or hysteresis, then the fuel flow rate may be changed to the higher flow rate. 
     The hysteresis may be a pre-programmed (for example during manufacture or coding) at 1° C. or 2° F., or some other higher or lower value suitable for cooking. As noted, higher numbers may lead to less accurate cooking, but may reduce the wear on any movable parts such as valve  38 . 
     The software of temperature control device  32  may be pre-programmed to include the following features:
         Off/Manual Mode—This mode permits a user to control the fuel rate manually.   Preheat Mode—The temperature control apparatus  32  controls the system to a predefined preheat set point and may sound or otherwise indicate an alert when the barbeque  20  is at a preheat temperature.   Grill Temp Mode—The temperature control apparatus  32  controls the barbeque  20  temperature to a user defined set point for each zone, when more than one zone is employed.   Timer Mode—This mode is similar to Grill Temp Mode, except that once the settable timer expires, the set points may be automatically reduced to the keep warm set points.   Probe Cook Mode—This mode is similar to Grill Temp Mode, except that once the probe temperature has reached the set point, the fuel rates of both zones may be reduced to minimum.       

     The software of temperature control device  32  may be pre-programmed to include one or more of the following safety features (the alarms may be auditory or visual or both, and may include a explanation of the nature of the alarm to be displayed on LCD  52 ): 
     1. Normal Alarm—this may be activated by temperature control device  32  when the measured temperature is not approaching the desired set point over time. In this situation, the software continues to control normally, but alerts the user with the display and an alarm, such as an audible beep, to the possibility of an undesirable condition such cover left open, or an out of fuel condition. 
     2. Overtemp Alarm—this may be activated by temperature control device  32  when the temperature, for example as measured by a thermocouple, exceeds a fixed programmable parameter. When this event occurs, an overtemp alarm may be triggered and the fuel flow rate reduced. 
     3. OverAcceleration Alarm—this may be activated by temperature control device  32  temperature, for example as measured by a thermocouple, increases or decreases (for example by ramping up or down) too quickly. In such case, an undesirable condition such as a grease fire may exist. The software of temperature control device  32  may then reduce the fuel flow rate, and may activate an alarm. 
     In an embodiment, temperature control device  32  may be programmed to include a probe cook mode. In the probe cook mode, a user may set the probe temperature set point based on the type of meat and the desired wellness. From the software, this is a series of pre-programmed set points used for each wellness state that may be selected (left to right in degrees Fahrenheit, the table illustrates the set point probe temperature for rare, medium rare, medium and well, respectively): 
     
       
         
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 {135,145,160,170}, // BEEF 
               
               
                   
                 {135,145,160,170}, // LAMB 
               
               
                   
                 {135,145,160,170}, // VEAL 
               
               
                   
                 {180,180,180,180}, // CHICKEN 
               
               
                   
                 {180,180,180,180}, // TURKEY 
               
               
                   
                 {170,170,170,170}, // PORK 
               
               
                   
                 {160,160,160,160}, // FISH 
               
               
                   
                 {160,160,160,160}  // HAMBURGER 
               
               
                   
                   
               
             
          
         
       
     
     In a yet further embodiment, the temperature control device  32  may be programmed to collect data from a tank level sensor that may provide an indication of the level of fuel in the tank and the time remaining at the current cook rate. This is done by monitoring the rate of change over time and predicting (extrapolating) the time when the tank will be out of fuel. 
     While the foregoing embodiments have been described in some detail for purposes of clarity and understanding, it will be appreciated by one skilled in the art, that numerous modifications, variations, and adaptations may be made to the particular embodiments described above without departing from the scope of the invention(s), which is defined in the following claims. In particular, many of the embodiments disclosed may be applied to other gas fueled devices and appliances with appropriate modification.