Abstract:
A matchbox oven is disclosed. The matchbox oven includes a housing, a slider, a mover, a heat source and a blower. The housing includes a cavity having two openings. The mover moves the slider in and out of the cavity through the two openings. The heat source provides heat to the cavity for heating up any food item placed within the cavity. The slider includes multiple stoppers to serve as oven covers for preventing heat within the cavity from escaping through the two openings. The slider can also be utilized as a heat sink for lowering the cavity&#39;s temperature during oven operation. When a new cook temperature is substantially lower than the temperature of the cavity, the blower forces heated air within the cavity to exit through the two openings before the starting of and/or during the initial portion of a new cook cycle.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This patent application is a division of U.S. application Ser. No. 13/774,617 filed on Feb. 22, 2013, which was a continuation of U.S. application Ser. No. 13/236,695, filed on Sep. 20, 2011, the pertinent parts of which are incorporated by reference herein. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable 
       BACKGROUND OF THE INVENTION 
       [0003]    1. Field of the Invention 
         [0004]    The present invention relates to ovens in general, and in particular to a matchbox oven capable of providing continuous food cooking while minimizing heat loss. 
         [0005]    2. Description of the Related Art 
         [0006]    A conveyor oven typically has a first opening through which uncooked food enters and a second opening at the opposite end of the oven through which cooked food exits. A stainless steel conveyor belt is commonly used to carry food items through a heated cavity between the first and second openings. The conveyor belt extends past both openings sufficiently to allow safe insertion and retrieval of food items. This arrangement allows food items to be placed on the conveyor belt on a continuous basis to achieve sequential steady-state cooking. 
         [0007]    When food items offered by a commercial foodservice operation such as a restaurant are to be cooked at the same heat transfer profile for the same amount of time, a conveyor oven is particularly advantageous. A foodservice personnel needs only set the temperature, blower speed and conveyor belt speed as necessary to cook the selected foods. After the above-mentioned three parameters have been set, the conveyor oven can be operated continuously without any further adjustments. As such, even a person unskilled in the art of cooking is able to prepare high-quality cooked food products simply by placing them on the conveyor belt of a conveyor oven. The ease of operation and high throughput make conveyor ovens highly desirable in restaurants and other commercial foodservice settings. 
         [0008]    However, conveyor ovens also have their disadvantages. For example, most commercial foodservice operations offer a variety of food items, such as pizza, chicken, vegetables and pies. Even a single food order at a restaurant may include multiple types of food items. Conveyor ovens are very efficient when cooking similar food items, but not so for cooking a variety of food items that require vastly different cooking times and heat transfer profiles. In addition, conveyer ovens are not very energy efficient because the two openings allow tremendous heat loss during their operation, and the lost heat must be replaced in order to maintain a steady cooking temperature. Furthermore, the heat that escapes from conveyor ovens must be extracted, typically via an air conditioning system, so that the ambient temperature of the kitchen area in which the conveyor ovens reside does not increase beyond an uncomfortable level for foodservice personnel. All of the above adds to the cost of foodservice operations when using conveyor ovens. 
         [0009]    Consequently, it would be desirable to provide a flexible oven that is energy-efficient as well as operationally efficient. 
       SUMMARY OF THE INVENTION 
       [0010]    In accordance with one embodiment of the present invention, a matchbox oven includes a housing, a slider, a mover and a heat source. The housing includes a cavity having a first and second openings. The mover moves the slider in and out of the cavity through the first and second openings. The heat source provides heat to the cavity for heating up any food item placed on a portion of the slider located within the cavity. The slider, which is configured to receive food items, includes multiple stoppers to serve as oven covers for preventing heat within the cavity from escaping through the first and second openings. When necessary, a portion of the slider can also be utilized as a heat sink for lowering the temperature in the cavity during oven operation. In addition, the matchbox oven includes a blower for forcing heated air within the cavity to exit through the first and second openings before starting a new cook cycle and/or during the initial portion of a new cook cycle when a new cook temperature is substantially lower than the temperature in the cavity. 
         [0011]    All features and advantages of the present invention will become apparent in the following detailed written description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The invention itself, as well as a mode of use, further objects, and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: 
           [0013]      FIG. 1  is a front view of a matchbox oven, in accordance with an embodiment of the present invention; 
           [0014]      FIG. 2  is a cross-sectional view of a cavity within the matchbox oven from  FIG. 1 ; 
           [0015]      FIG. 3  is a diagram of a heating and airflow system within the matchbox oven from  FIG. 1 ; 
           [0016]      FIGS. 4   a - 4   c  are a top view and side views of the slider within the matchbox oven from  FIG. 1 ; 
           [0017]      FIGS. 5   a - 5   c  illustrate a method of cooking when only one of food loading sections of the matchbox oven from  FIG. 1  is being used; 
           [0018]      FIGS. 6   a - 6   f  illustrate a method of cooking when both food loading sections of the matchbox oven from  FIG. 1  are being used; and 
           [0019]      FIGS. 7   a - 7   c  illustrate a method of rapidly reducing the temperature in the cavity from  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    Referring now to the drawings and in particular to  FIG. 1 , there is depicted a front view of a matchbox oven, in accordance with an exemplary embodiment of the present invention. As shown, a matchbox oven  10  is defined by a housing  11  having a cavity  12 . Housing  11 , as well as cavity  12 , has a first opening  18  and a second opening  19 . Matchbox oven  10  includes a heating and airflow system (not shown) to supply heat to cavity  12  for heating up any food items that have been carried into cavity  12  through either first opening  18  or second opening  19  via a slider  20 . 
         [0021]    Matchbox oven  10  also includes a first control panel  15  and a second control panel  16 . An operator can enter operating parameters, such as cooking temperature, cooking time, blower speed, etc., via first and second control panels  15 ,  16  to effectuate cooking controls on any food items placed within cavity  12 . First and second control panels  15 ,  16  are preferably implemented with touchscreens but they can also be implemented with keypads and liquid crystal displays (LCDs). 
         [0022]    With reference now to  FIG. 2 , there is depicted a cross-sectional view of housing  11  that accommodates slider  20  having a first food loading section  21  and a second food loading section  22 . The surfaces of first and second food loading sections  21 ,  22  are substantially planar. First and second food loading sections  21 ,  22  are configured to receive cooking plates  27 ,  28 , respectively. Any food item intended to be cooked by matchbox oven  10  is initially placed on either one of cooking plates  27 ,  28 . Cooking plates  27 ,  28  can be identical or different from each other, depending on the types of food items to be prepared. Thus, cooking plate  27  may be made of a different material and/or a different design from cooking plate  28 . 
         [0023]    Preferably, operating parameters for matchbox oven  10  to cook any food items placed on the first food loading section  21  to be carried into cavity  12  through first opening  18  can be entered at first control panel  15  (from  FIG. 1 ). Similarly, operating parameters for matchbox oven  10  to cook any food items placed on food loading section  22  to be carried into cavity  12  through second opening  19  can be entered at second control panel  16  (from  FIG. 1 ). 
         [0024]    When the first food loading section  21  is located inside cavity  12  where food is being cooked, the second food loading section  22  is located outside housing  11  where it is being cooled by the ambient air of a kitchen in which matchbox oven  10  resides. Similarly, when the second food loading section  22  is located inside cavity  12  where food is being cooked, the first food loading section  21  is located outside housing  11  where it is being cooled by the ambient air of the kitchen in which matchbox over  10  resides. Due to the large temperature differential between the cooled first food loading section  21  (or second food loading section  22 ) and cavity  12 , the first food loading section (or second food loading section  22 ) can be sent into cavity  12  to rapidly bring down the temperature of cavity  12 , when necessary, after first food loading section  21  (or second food loading section  22 ) has been sufficiently cooled down by the ambient air. In essence, the air-cooled first food loading section  21  (or second food loading section  22 ) serves as a heat sink for absorbing the heat within cavity  12 . From a time saving standpoint, this maneuver is particularly advantageous in getting matchbox oven  10  ready for cooking a food item that requires a lower cooking temperature than the current temperature of cavity  12 . This is because it takes less time to raise the temperature of cavity  12  up to the desired temperature by the heating and airflow system (after the cavity&#39;s current temperature has been lowered by one of food loading sections  21 - 22 ) than to lower the cavity&#39;s temperature down to the desired temperature by allowing heat to escape from cavity  12 . 
         [0025]    Slider  20  also includes a first stopper  23 , a second stopper  24  and a third stopper  25 . Third stopper  25  serves as a divider between first and second food loading sections  21 ,  22  as well as an oven cover to prevent heat within cavity  12  from escaping through openings  18 ,  19 . Along with third stopper  25 , first and second stoppers  23 ,  24  serve as oven covers to prevent heat within cavity  12  from escaping through openings  18 ,  19 , depending on the placement of slider  20  in relation to cavity  12 . For example, first and third stoppers  23 ,  25  can serve as oven covers for first and second openings  18 ,  19 , respectively. Similarly, third and second stoppers  25 ,  24  can serve as oven covers for first and second openings  18 ,  19 , respectively. 
         [0026]    Slider  20  is connected to a stepper motor (not shown) that powers the linear movement of slider  20  in and out of cavity  12 . Although slider  20  is moved by a stepper motor, it is understood by those skilled in the art that slider  20  can also be moved manually via a lever system or by a variety of other motorized movement designs. 
         [0027]    In addition, housing  11  also contains a top plenum  35  and a bottom plenum  38 . Top plenum  35  is connected to a top nozzle plate  34 . Bottom plenum  38  is connected to a bottom nozzle plate  37 . Top nozzle plate  34 , top plenum  35 , bottom nozzle plate  37  and bottom plenum  38  are part of the heating and airflow system for matchbox oven  10  such that heated air in top plenum  35  and bottom plenum  38  are in gaseous communication with cavity  12  through top nozzle plate  34  and bottom nozzle plate  37 , respectively. Top nozzle plate  34  and bottom nozzle plate  37  include multiple conical shape nozzles for directing hot pressured airstream towards any food items placed on the portion of slider  20  located within cavity  12 . Although air passes through top nozzle plate  34  and bottom nozzle plate  37  into cavity  12 , it is understood by those skilled in the art that top plenum  35  and/or bottom plenum  38  could be in gaseous communication with cavity  12  via a variety of air opening configurations such as tubes, rectangular openings and the like, and that air could enter cavity  12  through only one of the top plenum  35  or bottom plenum  38 . 
         [0028]    For additional heating, an optional infrared radiation heating element  36  can be placed within cavity  12  somewhere between slider  20  and bottom nozzle plate  37  or between slider  20  and top nozzle plate  34  for supplying heat towards any food located on first food loading section  21  or second loading section  22  of slider  20 . It is understood by those skilled in the art that other heating elements, such as microwave, steam or a combination thereof, can be used instead of infrared radiation heating element  36 . 
         [0029]    Referring now to  FIG. 3 , there is depicted a diagram of the heating and airflow system within matchbox oven  10 . Air within cavity  12  is initially pumped in to a heater plenum  31  via an intake opening  30 . Heater plenum  31  includes a heater  39 . After it has been sufficiently heated by heater  39 , the hot air is then directed to top plenum  35  via a top blower  32  and to bottom plenum  38  via a bottom blower  33 . The pressurized hot air formed within top plenum  35  is subsequently directed to cavity  12  via multiple nozzles located on top nozzle plate  34  (from  FIG. 2 ). Similarly, pressurized hot air formed within bottom plenum  38  is subsequently directed to cavity  12  via multiple nozzles located on bottom nozzle plate  37  (from  FIG. 2 ). Although heated air is shown to be sent to top air plenum  35  and bottom air plenum  38  via separate blowers, it is understood by those skilled in the art that heated air can be sent to both top plenum  35  and bottom plenum  38  via a single blower. 
         [0030]    With reference now to  FIG. 4   a , there is depicted a top view of the slider  20 , which includes first and second food loading sections  21 - 22  and stoppers  23 - 25 , is supported by a first pair of rails  42 ,  43  and a second pair of rails  44 ,  45 . The linear movement of slider  20  on top of rails  42 - 45  is preferably powered by a stepper motor  41 . The widths of stoppers  23 - 25 , which are preferably the same, are wider than the thickness of openings  18 ,  19 . Thus, two of stoppers  23 - 25  can serve as oven covers to prevent heat within cavity  12  from escaping through openings  18 ,  19 , depending on the placement of slider  20  in relation to cavity  12 . Although three stoppers  23 - 25  on the exemplary slider, it is possible to employ less than three stoppers on slider  20  at the expense of a higher heat loss from cavity  12 . 
         [0031]      FIGS. 4   b - 4   c  depict two side views of the slider  20 . In  FIG. 4   b , first food loading section  21  is shown to be located within cavity  12 , with first and third stoppers  23 ,  25  positioned centrally within first and second openings  18 ,  19 , respectively. In this position, first and third stoppers  23 ,  25  serve as oven covers for first and second openings  18 ,  19 , respectively. In  FIG. 4   c , second food loading section  22  is shown to be located within cavity  12 , with third and second stoppers  25 ,  24  positioned centrally within first and second openings  18 ,  19 , respectively. In this position, third and second stoppers  25 ,  24  serve as oven covers for first and second openings  18 ,  19 , respectively. 
         [0032]    In  FIGS. 4   b - 4   c,  stoppers  23 - 25  are shown to be positioned centrally within openings  18 - 19 . However, during a cooking cycle, slider  20  can be moved to-and-fro slightly and repeatedly to allow the edges of two of stoppers  23 - 25  to be flush with openings  18 - 19  of housing  11 . Such movements are designed to avoid overheating of a food item at any spot located directly underneath a nozzle. The distance within which slider  20  can be moved to-and-fro is preferably dictated by the widths of stoppers  23 - 25  in order to avoid heat loss from cavity  12  during such movements. 
         [0033]    Referring now to  FIGS. 5   a - 5   c,  there are illustrated a method of cooking when only one of food loading sections  21 ,  22  of slider  20  is used, in accordance with a preferred embodiment of the present invention. An uncooked raw food item (RF) is initially placed on food loading section  22  (or  21 ), as shown in  FIG. 5   a . An operator then enters an appropriate cook settings for cooking the food item via control panel  16  (or  15 ), and food loading section  22  (or  21 ) is subsequently moved within cavity  12 , as depicted in  FIG. 5   b . After a period of time has lapsed, food loading section  22  (or  21 ) exits cavity  12 , and the fully cooked food item (CF) is ready to be removed from food loading section  22  (or  21 ) by an operator, as shown in  FIG. 5   c.    
         [0034]    With reference now to  FIGS. 6   a - 6   f,  there are illustrated a method of cooking when both food loading sections  21 ,  22  of slider  20  are being used, in accordance with a preferred embodiment of the present invention. A first uncooked raw food item (RF- 1 ) is initially placed on food loading section  22 , and an operator then enters an appropriate cook setting for cooking the first food item via control panel  16 , as shown in  FIG. 6   a . Food loading section  22  is subsequently moved inside cavity  12 , as depicted in  FIG. 6   b . While the first food item is being cooked (F- 1 -C), a second uncooked raw food item (RF- 2 ) can be placed on food loading section  21 , and the operator enters an appropriate cook settings for cooking the second food item via control panel  15 , as depicted in  FIG. 6   c . After a period of time has lapsed, food loading section  22  on which the first food item is fully cooked (CF- 1 ) exits cavity  12  while food loading section  21  is moved inside cavity  12 , as shown in  FIG. 6   d . While the second food item is being cooked (F- 2 -C), the fully cooked first food item (CF- 1 ) is ready to be removed by the operator from food loading section  22 , as shown in  FIG. 6   e.    
         [0035]    While the second food item is being cooked (F- 2 -C), a third uncooked raw food item (RF- 3 ) can be placed on food loading section  22 , and the operator enters an appropriate cook settings for cooking the third food item via control panel  16 , as depicted in  FIG. 6   f.    
         [0036]    The above-mentioned sequence can be performed repeatedly for different food items. Since different cooking times can be entered by a foodservice personnel, any of the above-mentioned food items can be completely different from each other. When the cooking temperature of a to-be-cooked food item is relatively close to the temperature of cavity  12 , no adjustment is typically required. When the cooking temperature of a to-be-cooked food item is higher than the temperature of cavity  12 , heater  39  (from  FIG. 3 ) will be turned on, and heated air will be directed to cavity  12  via top blower  32  and bottom blower  33  in order to increase the temperature of cavity  12 . The time for heating up cavity  12  should be relatively short (i.e., no wait time) due to the placement of stopper  23 - 25  within openings  18 - 19 . 
         [0037]    When the cooking temperature of a to-be-cooked food item is lower than the temperature of cavity  12 , it is important to lower the temperature of cavity  12  before starting the cooking process again, or else there may be a risk of overcooking the food item. The time for cooling down cavity  12  to the desired temperature may take several minutes, which is usually not acceptable in a fast pace commercial kitchen. Thus, the temperature of cavity  12  needs to be rapidly lowered by the following methods. If the newly entered cook temperature is approximately 40° F. (or approximately 10% in degrees Fahrenheit) less than the temperature of cavity  12 , cavity&#39;s temperature can be rapidly lowered by sending either one of food loading sections  21 ,  22  inside cavity  12 . This is because one of food loading sections  21 ,  22 , which has been cooled by the ambient air of a kitchen, can serve as a heat sink to absorb the heat within cavity  12 . 
         [0038]    However, if the newly entered cook temperature is substantially lower than the temperature of cavity  12  (such as more than 40° F. or 10% in degrees Fahrenheit), the temperature of cavity  12  needs to be further lowered by using a different method, in conjunction with the usage of one of food loading sections  21 ,  22  as a heat sink, in order to avoid any overcooking. The temperature of cavity  12  can be further lowered rapidly as follows. Referring now to  FIGS. 7   a - 7   c,  after a raw food item RF has been placed on loading section  22  (or  21 ), as depicted in  FIG. 7   a , a foodservice personnel can enter a desired cook temperature for cooking the food item RF via control panel  16  (or  15 ). If the desired cook temperature is substantially lower than the temperature of cavity  12 , top and bottom blowers  32 ,  33  (from  FIG. 3 ) will be activated as soon as food loading section  22  (or  21 ) begins moving into cavity  12 . At this point, the forced air from top blower  32  and bottom blower  33  push the heated air within cavity  12  out via openings  18 ,  19 , thereby lowering the temperature of cavity  12 . Food loading section  22  (or  21 ) may then be moved partially but not completely within cavity  12  such that openings  18 ,  19  are not covered by stoppers  24 ,  25  (or  23 ,  25 ), as depicted in  FIG. 7   b . In this position, heated air within cavity  12  is allowed to escape until the temperature of cavity  12  is reduced to the desired temperature, and at which point, food loading section  22  (or  21 ) is moved completely within cavity  12  with openings  18  and  19  completely covered by stoppers  25  and  24  (or  23  and  25 ), respectively, as shown in  FIG. 7   c.    
         [0039]    Alternatively, instead of waiting for the temperature of cavity  12  to drop to the desired temperature before the cooking cycle begins, the cooking cycle can start and slider  20  can be “over moved” to-and-fro repeatedly to permit the edges of two of stoppers  23 - 25  to travel beyond openings  18 - 19  of housing  11  such that hot air is allowed to escape from cavity  12 , as can be illustrated by moving loading section  22  between the positions shown in  FIGS. 7   b  and  7   c  repeatedly. After the temperature of cavity  12  has been reduced to the desired temperature, the normal to-and-fro movements (from  FIGS. 4   b - 4   c ) by slider  20  will resume. 
         [0040]    For much of the duration of the cook cycle, the preset temperature of matchbox oven  10  at which the temperature feedback loop operates is temporarily lowered to the new temperature entered by the foodservice personnel. Once the cook cycle is near completion, the preset temperature of matchbox oven  10  reverts back to the original preset temperature so that the next cooking cycle will not start from an unacceptably low starting temperature. 
         [0041]    While the invention has been particularly shown and described with an exemplary embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.