FIELD OF THE INVENTION  
       [0001]    The present invention provides a combustion device and method for effectively removing odor-producing materials, more specifically, an oven containing a device for thermal decomposition of odor-producing materials that occur when foods are heated in cooking cavity. 
       DESCRIPTION OF RELATED ARTS  
       [0002]    Conventional cooking utensils have no function to remove volatile compounds and smells generated during cooking. The present invention relates to a device and method for effectively removing odor-producing materials in an oven cavity. Smoke or fumes generated during cooking make people feel unpleasant and may contain various harmful materials that cause damage to human health. In order to solve the above problems, a range hood for discharging fumes outside is installed in the kitchen. However, because the range hood is located relatively far from the place where cooking is carried out, the cooking, fumes are diffused to the kitchen and other rooms while the user prepares foods on the range. 
         [0003]    The oven is a cooking utensil that heats food in a cooking cavity in which heating elements are installed. The oven simultaneously heats the surface and the inside of food so as to effectively cook bulky food, and hence, the use of the oven is on the rise. However, the conventional ovens have no functions to purify contaminants such as smoke or fumes generated during cooking. Some of the ovens have self-cleaning functions to cause pyrolysis at temperatures of about 400-500° C. in order to remove food contaminants stained and accumulated on the walls of the cooking cavity. However, the above case adopts a method of re-heating the cooking cavity after taking out the food and cannot solve the problem of diffusing fumes during cooking. Therefore, a device for effectively removing fumes generated during cooking is desired. 
         [0004]    The following patents are known in the art and are incorporated by reference herein: Korean Pat. Nos. 10-0518444; 10-0555420; and U.S. Pat. Nos. 6,316,749; 6,318,245; 7,878,185; 8,101,894. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention relates to a combustion device and method for effectively removing odor-producing materials in an oven cavity. An object of the present invention is to provide a multi-purpose combustion device that includes a heating means adapted to heat up food in the cooking cavity, and also to provide a cleaning effect. In detail, another object of the present invention is to solve problems of inconvenience due to contamination of cooking fumes by providing an oven having pyrolysis function. 
         [0006]    Conventional ovens comprise a cooking cavity, heaters for heating the cooking cavity, a temperature sensor for sensing the operating temperature of the cooking cavity, a convection chamber for circulating air, a control panel for controlling the heaters and the convection chamber, and an oven body. 
         [0007]    According to an aspect of the present invention, the oven further comprises a heating means, a combustion tube, a combustion space, a connection tube, and a flow supply unit, as well as the components of a conventional oven as described above. 
         [0008]    The cooking cavity adapted to receive food is surrounded by cavity walls and an oven door. The heating means is located within the cooking cavity, and is enclosed by a combustion tube. A combustion space is formed between the heating means and the combustion tube. The flow supply unit connects to the combustion tube via a connection tube, moves air in the cooking cavity to the combustion space, and expels the cleaned air outside. The flow supply unit includes a fan that can generate a stream of air. The connection tube is configured to transfer an air pressure differential to the combustion tube to maintain the pressure within the cooking cavity lower than the atmospheric pressure. 
         [0009]    The fan is adapted to introduce the steam inclusive of the odor-producing materials in the cooking cavity into the combustion space. The connection tube is configured to transfer an air pressure differential to the combustion tube and to move the air in the cooking cavity. 
         [0010]    The odor-producing materials are prevented from spreading out of the cooking cavity and are pyrolyzed by passing through the combustion space heated to over 700° C., over a period of at least 0.5 seconds. 
         [0011]    It is preferable that a venturi tube is connected between the fan and the connection tube. The venturi tube is connected between the outlet of the fan and the connection tube in such a way as to communicate air. The venturi tube includes a nozzle which has a narrow air path and is connected to the outlet of a fan. The flow of air from the fan becomes faster at the nozzle, which creates low pressure at the side of the nozzle where an inlet hole is thrilled. Because the connection tube is connected between the inlet hole and the combustion tube, the pressure differential created by the fan causes air in the cooking cavity to enter into the combustion space and move toward the inlet hole. 
         [0012]    The oven of the present invention further includes a convection chamber located on the rear side cavity walls that forcibly circulates air in the cooking cavity. 
         [0013]    The combustion process for removing contaminants m the oven according to the present invention includes the steps of: 1) supplying electric power to the heating means to increase temperature of the combustion space to 700° C. or to the preset temperature; 2) operating the flow supply unit to start thermal decomposition of the contaminants when the temperature of the combustion space reaches 700° C. or the preset temperature; 3) operating the heating means and the flow supply unit during the preset cooking time to decompose contaminants generated during cooking; and 4) terminating the power supply to the heating means and the flow supply unit. 
         [0014]    A control panel is installed on the oven body to control the combustion process. The control panel includes at least one controlling means for setting the timer and operating modes which control the heating means and the fan. 
         [0015]    The oven has high energy efficiency since the heating means both carries out thermal decomposition of the odor-producing materials and heats food by supplying radiant heat to the cooking cavity 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a front view showing an oven  10  having combustion function according to a first preferred embodiment of the present invention. 
           [0017]      FIG. 2  is a side sectional view taken along the line  2 - 2  of  FIG. 1 . 
           [0018]      FIG. 3  is a sectional view taken along the line  3 - 3  of  FIG. 2 . 
           [0019]      FIG. 4  is a configurative view of some components showing a flow of air in the oven  10 . 
           [0020]      FIG. 5  is a sectional view showing an oven  10 ′ having combustion function according to a second preferred embodiment of the present invention. 
           [0021]      FIG. 6  is a perspective view of a heating means  30  and a combustion tube  35 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    The objects and features of the present invention will be now made in detail to the preferred embodiments of the present invention with reference to the attached drawings. 
       First Embodiment 
       [0023]      FIG. 1  is a front view showing an oven  10  having a combustion device according to a first preferred embodiment of the present invention. An oven door  20  having a door knob  21  is rotatably attached to an oven body  26  forming the outward appearance of the oven  10 . The oven door  20  seals the front side of a cooking cavity  29  to prevent volatile compounds or fumes from escaping from the cooking cavity, to make racks easily go in and out of the cooking cavity, and to allow a user to check the level of cooked foods in the cooking cavity. A control panel  22  is disposed at one side of the front face of the oven body  26 . The control panel  22  includes at least one controlling means for setting temperature and time so that the inside of the cooking cavity  29  can keep a preset temperature for an appropriate period of time. 
         [0024]      FIG. 2  is a side sectional view taken along the line  2 - 2  of  FIG. 1  showing the inside configuration of the cooking cavity  29  and the oven body  26 , and  FIG. 3  is a sectional view taken along the line  3 - 3  of  FIG. 2 . Referring to the drawings, the present invention will be described in detail as follows. The cooking cavity  29  is surrounded by a cavity wall  23 , has an open front face, and has a space for cooking foods inside. The cooking cavity  29  has a heater  25  mounted inside the cavity for heating foods at the proper temperature. Moreover, the cooking cavity  29  further includes a heating means  30  mounted at the upper part of the cavity and a combustion tube  35  having a hollow portion formed to enclose the heating means  30 . A combustion space  33  is formed between the heating means  30  and the combustion tube  35 . 
         [0025]    The heating means  30  can generate heat and raise the temperature of the combustion space  33  at least 700° C. or preset temperature. It is preferable that the heating means  30  is selected from a group consisting of a sheath heater, a cartridge heater, or a heat wire wound in a coil form connected to a power supply. 
         [0026]    The combustion tube  35  is selected from a group consisting of ceramics, a quartz tube, or heat-resisting metals and is formed in a hollow tube shape with both ends open. It is preferable that the combustion tube is enclosed by a heat resisting metallic cover (not shown) in order to protect it from external impacts. 
         [0027]    The cooking cavity  29  further includes a convection chamber  32  for forcibly circulating the air within the cooking cavity  29 . The convection chamber  32  is located at the rear side of the cooking cavity  29  and receives power generated from a motor, such that a fan inside the chamber works to inhale the air of the cooking cavity and to discharge air back to the cooking cavity  29 . Because there is a temperature difference over 600° C. between the center of the cooking cavity and the top portion near the combustion tube  35 , the air is forcibly convected by the convection chamber  32  and it rapidly increases the temperature of the cooking cavity  29 . 
         [0028]    The cooking cavity  29  includes a temperature sensor  24  for sensing temperature of the cooking cavity  29 . The temperature sensor  24  mounted on the cavity wall  23  detects the inside temperature of the cooking cavity  29  and interrupts or connects electricity to the heater  25  and the convection chamber  32 . 
         [0029]    A flow supply unit  40 , connected to the combustion tube  35 , maintains the pressure within the cooking cavity  29  lower-than-the-atmospheric pressure and expels the steam inclusive of odor-producing materials in the cooking cavity  29  outside. The flow supply unit  40  includes a venturi tube  42  and a fan  43 . The fan  43  is a centrifugal fan that has an inlet and an outlet and serves to create a flow of air. Namely, the fan  43  forms a vacuum state at the inlet (not shown) of the fan  43  and generates an air flow at the outlet (not shown) of the fan  43  by forming a pressure differential when its blades rotate. Therefore, an air pressure lower-than-the-atmospheric pressure can be generated in the combustion space  33  by the flow supply unit  40 , which causes smoke and odor-producing materials in the cavity to get sucked into the combustion space  33  to be thermally decomposed. Additionally, the flow supply unit  40  prevents contaminants generated during cooking from spreading out, inhales air from the combustion tube  35 , and discharges air out of the oven  10 . The connection tube  41  is connected to the middle section of the combustion tube  35  and transfers the steam and air including carbon dioxide from the combustion tube  35  to the venturi tube  42 . 
         [0030]    The venturi tube  42  is connected between the outlet (not shown) of the fan  43  and the connection tube  41  to communicate air. The venturi tube  42  includes a nozzle  45  disposed at the middle portion thereof which makes a narrower air path, and hence, the venturi tube  42  has a structure that its air path becomes narrowed near the nozzle  45  and becomes widened again. An inlet hole  46  is formed on the side of the nozzle in the venturi tube  42 . The inlet of the venturi tube  42  is connected to the outlet of fan  43 , and hence, the flow of air from the fan  43  becomes faster at the nozzle  45 , which creates a low pressure (vacuum state) at the inlet hole  46 . Because one side of the connection tube  41  is connected to the inlet hole  46 , and the opposite side of the connection tube  41  is connected to the middle section of the combustion tube  35 , a pressure difference (vacuum) is generated in the venturi tube  42  that causes the air of the cooking cavity  29  to get sucked into the combustion space  33  and to move towards the inlet hole  46 . Furthermore, as described above, because the venturi tube  42  is connected to the outlet of the fan  43 , vapor and air of high temperature from the combustion space  33  are eventually discharged out of the venturi tube  42  without being in direct contact with the fan  43 . 
         [0031]      FIG. 4  is a configurative view of some main parts showing a flow of air in the oven  10 . Referring to the drawing, the combustion process of contaminants in the cooking cavity  29  will be described in detail. First, when electric power to the oven  10  is supplied, the heating means  30  is heated so that temperature of the combustion space  33  increases. When the combustion space  33  reaches a temperature over 700° C. or a preset temperature, the fan  43  starts to operate. The air current by the fan  43  forms pressure difference (vacuum) in the connection tube  41  through the inlet hole  46  of the venturi tube  42 . The vacuum is transferred to the combustion space  33  inside the combustion tube  35  and inhales the contaminants from the cooking cavity  29  through both open ends of the combustion tube  35 . During the preset cooking time, the heating means  30  and the fan  43  are turned on so as to thermally decompose the contaminants generated during cooking. The combustion cycle comes to an end when the supply of electricity to the heating means  30  and the fan  43  is terminated. 
       Second Embodiment  
       [0032]      FIG. 5  is a sectional view showing an oven  10 ′ having combustion function according to a second preferred embodiment of the present invention. The oven  10 ′ according to the second preferred embodiment has the same components as the oven  10  according to the first preferred embodiment except for the flow supply unit  40 . As illustrated in the drawing, the inlet (not shown) of the fan  43  is connected with the connection tube  41 , and vacuum generated by the fan  43  is transferred to the combustion tube  35  through the connection tube  41 , so that the air of high temperature inside the combustion space  33  enters into the fan  43  and is discharged through the outlet (not shown) of the fan  43 . Accordingly, it is preferable that the flow supply unit  40 ′ uses the fan  43  being made of a heat-resistant material, which can be operated at high temperature enough to endure hot air from the combustion space  33 , or lower the temperature of hot air from the combustion space  33  before it is inhaled into the fan  43 . 
         [0033]    As described above through the embodiments, in order to completely decompose contaminants generated during cooking, it is preferable that the combustion space  33  maintains its temperature over 700° C. and the contaminants pass through the combustion space  33  over a period at least 0.5 seconds. The time (t) that the contaminants pass through the combustion space  33  can be controlled, and it is indicated by the Mathematical Formula 1 and a drawing illustrated in  FIG. 6 . 
         [0000]    
       
         
           
             
               
                 
                   t 
                   = 
                   
                     
                       L 
                       V 
                     
                     = 
                     
                       
                         
                           
                             ( 
                             
                               A 
                               - 
                               a 
                             
                             ) 
                           
                           · 
                           L 
                         
                         Q 
                       
                       ≥ 
                       
                         0.5 
                          
                         
                           ( 
                           second 
                           ) 
                         
                       
                     
                   
                 
               
               
                 
                   [ 
                   
                     Mathematical 
                      
                     
                         
                     
                      
                     Formula 
                      
                     
                         
                     
                      
                     1 
                   
                   ] 
                 
               
             
           
         
       
     
         [0000]    wherein t is the period of time that air containing contaminants passes through the combustion space, L is the length (m) of the combustion tube. A is a cross-sectional area of the combustion tube (m 2 ), a is a cross-sectional area of the heating means (m 2 ), (A-a) is a cross-sectional area of the combustion space (m 2 ), Q is a flow rate (m 3 /second), and V is a speed (m/second) of the air flowing through the combustion space. 
         [0034]    The time that the air containing contaminants passes through the combustion space  33  may he kept over 0.5 seconds by controlling the length of the combustion tube  35 , the cross-sectional area of the combustion space  33 , the flow rate of the air inhaled into the combustion space  33 , and the speed of the air flowing through the combustion space  33 . Particularly, it is natural that the flow rate and speed of the air flowing through the combustion space  33  can be sufficiently controlled through control of the operation conditions of the fan  43 . 
         [0035]    The combustion process for removing contaminants according to the present invention includes the steps of: 1) supplying electric power to the heating means  30  to increase temperature of the combustion space  33  to 700° C. or to the preset temperature; 2) operating the fan  43  to start thermal decomposition of the contaminants when the temperature of the combustion space  33  reaches 700° C. or the preset temperature; 3) operating the heating means  30  and the fan  43  during the preset cooking time to decompose contaminants generated during cooking; and 4) terminating the power supply to the heating means  30  and the fan  43 . 
         [0036]    A control panel  22  is disposed at one side of the front face of the oven body  26 . The control panel  22  includes at least one controlling means for setting the timer (not shown) and operating modes which control the heating means  30  and the fan  43 . 
         [0037]    While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. 
         [0000]    
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 LIST OF NUMERALS 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 10, 10’: oven 
                 20: oven door 
               
               
                   
                 21: door knob 
                 22: control panel 
               
               
                   
                 23: cavity wall 
                 24: temperature sensor 
               
               
                   
                 25: heater 
                 26: oven body 
               
               
                   
                 29: cooking cavity 
                 30: heating means 
               
               
                   
                 32: convection chamber 
                 33: combustion space 
               
               
                   
                 35: combustion tube 
                 40, 40’: flow supply unit 
               
               
                   
                 41: connection tube 
                 42: venturi tube 
               
               
                   
                 43: fan 
                 45: nozzle 
               
               
                   
                 46: inlet hole
The oven having combustion function includes a cooking cavity; a heating means for emitting heat; a combustion tube for surrounding the heating means, and the combustion tube also being in fluid communication with the cooking cavity and a flow supply unit; a combustion space wherein odor-producing materials are removed by the heat from the heating means, the combustion space formed between the heating means and the combustion tube; a flow supply unit connected to the combustion tube for developing a flow of air through the combustion space; and a connection tube for connecting the flow supply unit to the combustion tube. The odor-producing materials are pyrolyzed by staying at least 0.5 seconds in the combustion space heated over 700deg C. The oven has high energy efficiency since the heating means carries out thermal decomposition of the odor-producing materials and heats food by supplying radiant heat to the cooking cavity