Patent Publication Number: US-2010108053-A1

Title: Heating cooking appliance

Description:
TECHNICAL FIELD 
     The present disclosure relates to a heating cooking appliance. 
     BACKGROUND ART 
     A heating cooking appliance is a kitchen appliance that can cook food over a heat. Particularly, the present disclosure relates to a gas cooktop that can cook food over heat generated by gas combustion. The cooktop may also be called a hot plate or hob, which has been increasingly used in recent years. 
     The heating cooking appliance includes a burner system that combusts gas. A plate is heated by the combusted gas to cook the food lying on a top surface thereof. The heating cooking appliance using gas combustion requires improvements in combustion efficiency. 
     In the burner system, a control unit for, for example, the gas combustion and the like is provided on a side portion of the burner system. Here, the control unit may be easily damaged or malfunction due to the heat generated from the burner system. Therefore, there is a need to prevent damage to the control unit from high heat. 
     DISCLOSURE OF INVENTION 
     Technical Problem 
     Embodiments provide a heating cooking appliance that is designed to prevent damage of a control unit by a high heat. 
     Technical Solution 
     In one embodiment, a heating cooking appliance includes a case, a plate covering a top of the case, a burner system generating heat by combusting mixture gas in the case, a control unit controlling operation of the burner system, and a temperature increase preventing unit preventing a temperature of the control unit from increasing by the heat generated from the burner system. The temperature increase preventing unit is installed on the case. The temperature increase preventing unit includes a barrier and a fan. 
     Advantageous Effects 
     As the internal space of the case is divided by the barrier, the heat transmission to the control unit is blocked, thereby preventing the control unit from malfunctioning or being damaged. 
     Furthermore, since the control unit is cooled by the air flowing by means of the fan, the malfunctioning and damage of the control unit can be further prevented. 
     In addition, the barrier blocks the air flowing toward the burner system by the fan so as not to affect the flow of the air to the mixing pipe unit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a heating cooking appliance according a first embodiment of the present disclosure. 
         FIG. 2  is an exploded perspective view of the heating cooking appliance of  FIG. 1 . 
         FIGS. 3 and 4  are top plane views of the heating cooking appliance of  FIG. 1 . 
         FIG. 5  is a perspective view of a barrier according to the first embodiment. 
         FIG. 6  is an enlarged view of a portion A in  FIG. 4 . 
         FIG. 7  is a perspective view of a burner system according to the first embodiment. 
         FIG. 8  is an exploded perspective view of the burner system of  FIG. 7 . 
         FIG. 9  is a sectional view taken along line I-I of  FIG. 1 . 
         FIG. 10  is a perspective view of a sub-heating unit according to the first embodiment. 
         FIG. 11  is a graph comparing radiant energies in accordance with whether there is a sub-heating unit or not. 
         FIG. 12  is a top plane view of an inflowing path of air passing through a burner pot according to the first embodiment. 
         FIG. 13  is a view of a spark plug according to a second embodiment. 
         FIG. 14  is a perspective view of a sub-heating unit according to a third embodiment. 
     
    
    
     MODE FOR THE INVENTION 
     First Embodiment 
       FIG. 1  is a perspective view of a heating cooking appliance according a first embodiment of the present disclosure and  FIG. 2  is an exploded perspective view of the heating cooking appliance of  FIG. 1 . 
     Referring to  FIGS. 1 and 2 , a heating cooking appliance of a first embodiment includes a case  2  defining a lower appearance of the heating cooking appliance and having an opened top, a ceramic plate  1  seating on a top of the case  2 , and a top plate  3  covering an edge of the ceramic plate  1 . 
     The heating cooking appliance an exhaust grill  31  that is formed on a rear portion of the heating cooking appliance to exhaust combusted gas and a switch  29  that is formed on a front portion of the ceramic plate  1  to control an on/off of the gas combustion. 
     The locations and structures of the exhaust grill  31  and the switch  29  may be varied. However, it will be understood that an exhaust portion for exhausting the combusted gas and a switch portion for controlling the on/off of the gas combustion must be provided. 
     A plurality of components for controlling operation of the heating cooking appliance, such as the gas combustion, the exhaust of the combusted gas, and the like, are disposed in an inner space defined by the case  2  and the ceramic plate  1 . The following will describe an internal structure of the heating cooking appliance. 
     First, three burner pots  4  in which gas and air are sufficiently mixed to realize uniform combustion are provided. A mixing pipe unit  6  is disposed on a side surface of each of the burner pots  4  to supply mixture gas through the side surface of the burner pot  4 . 
     A nozzle unit  5  is disposed at a predetermined distance from an inlet of the corresponding mixing pipe unit  6  to inject the gas toward the inlet of the mixing pipe unit  6 . 
     Burner frames  11  are disposed above the respective burner pots  4 . Each of the burner frames  11  secures the disposed position of the corresponding burner pot  4  and defines an exhaust passage of the gas combusted in a corresponding glow plate  12 . 
     Disposed in rear of the burner frames  11  are an exhaust unit  10  for exhausting the combusted gas to an external side and the exhaust grill  31  disposed above the exhaust unit  10 . 
     The glow plates  12  are disposed on the opened top of the burner pot  4 . The glow plates  12  are heated by a high heat generated by the combustion of the mixture gas. When the glow plate  12  is heated, a radiant energy having a frequency band corresponding to a physical property of the glow plate  12 . 
     In more detail, the radiant energy from the glow plate  12  includes a frequency of at least a visible light band that allows a user to identify that the heating cooking appliance is operating. Needless to say, it can be understood that the food is heated by the glow plate  12  as well as the conduction heat of the ceramic plate  1 . 
     Sub-heating units  15  are provided above the respective burner frames  11  to radiate radiant energy by being heated by the heat from the respective glow plates  12 , thereby increasing total radiant energy. The sub-heating units  15  will be described in more detail with reference to the accompanying drawings later. 
     The following will describe a gas supplying structure to each of the nozzle units  5 . 
     The gas is supplied into the heating cooking appliance through a main gas supply unit  8  and the gas supply to each of the burner systems is controlled by gas valves  7  controlled by the respective switches  29 . In addition, the gas is supplied to respective gas supply pipes  9 . 
     Here, the burner system is a portion where the mixture gas is supplied and combusted. The burner system includes the nozzle unit  5 , the mixing pipe unit  6 , the burner pot  4 , the glow plate  12 , and the sub-heating unit  15 . 
       FIGS. 3 and 4  are top plane views of the heating cooking appliance of  FIG. 1 . That is,  FIG. 3  shows a state where the ceramic plates are removed and  FIG. 4  shows a state where a barrier for dividing the inner space of the case into separated spaces in  FIG. 3 . 
     Referring to  FIGS. 3 and 4 , two relatively large burner pots  4  are disposed on both sides of the case  2  and one relatively small burner pot  4  is disposed between the relatively large burner pots  4 . Therefore, a utensil is disposed and heated on one of the burner pots  4 , which has a heat value proper for the utensil. 
     The mixture gas is supplied to the relatively small burner pot  4  in a front-to-rear direction of the heating cooking appliance so as to perfectly mix the air and gas with each other through a secondary mixing process. The mixture gas is exhausted toward the exhausting unit  10  on the glow plates  12  after being combusted. 
     On the other hand, the mixture gas is supplied to the relatively large burner pots  4  in a rear-to-front direction of the heating cooking appliance. The mixture gas is secondarily mixed in the burner pots  4  and combusted on the glow plates  12 , after which the combusted mixture gas is exhausted rearward of the burner pot  4 . 
     Such an arrangement of the burner pots  4  is for realizing an optimal arrangement of the heating burner systems. The arrangement of other components can be identified through  FIGS. 3 and 4 . 
     In more detail, the case  2  is provided with a temperature increase preventing unit for preventing the increase in temperatures of the components disposed in the case  2 . 
     The temperature increase preventing unit includes a barrier  20  for dividing the inner space of the case  2  into a first space  2   a  where the burner systems are disposed and thus a high heat is generated and a second space  2   b  where non-heating components are disposed and thus a low heat is generated. 
     The barrier  20  functions to prevent the heat generated in the first space  2   a  from being transferred to the components disposed in the second space  2   b . Therefore, the barrier  20  may be called a heat blocking unit. 
     Disposed in the second space  2   b  defined by the barrier  20  are the main gas supply pipe  8 , a plurality of connecting pipes  8   a  connected to the main as supply pipe  8 , and a plurality of individual gas supply pipe  9  connected to the respective connecting pipes  8   a . The gas valves  7  are connected to the respective connecting pipes  8 . An ignition transformer  17  applying a current for igniting the mixture gas is disposed in the second space  2   b.    
     The temperature increase preventing unit includes a fan  19  for cooling the components disposed in the second space  2   b . The fan  19  is disposed at a side of the ignition transformer  17 . An air current generated by the fan  19  is introduced through a hole (not shown) formed through the case  2  corresponding to a portion where the fan  19  is located. 
     Since the components disposed in the second space  2   b  are comprised of the gas valves  7 , the ignition transformers  17 , and the like, these may be generally referred to as control unit. Since the components disposed in the first space  2   a  are the burner systems generating the high heat, these may be called heating unit. 
     Further, a lamp unit  18  is provided at a side of the control unit to let a user know, when the burner system generate a heat higher than a predetermined temperature, the fact. That is, the lamp unit  18  lets the user know the fact that the ceramic plate  1  is heated by the operation of the burner system, thereby preventing the user from being injured by the heat transmitted to the ceramic plate  1 . 
     Meanwhile, a spark plug  16  for igniting the mixture gas protrudes into the internal space of each of the burner frame  11 . The spark plugs  16  generate sparks by a current supplied from the ignition transformer  17 . 
     That is, the mixture gas is ignited by the ignition spark generated by the spark plug  16  and combusted on the glow plate  12 . Then, the glow plate  12  is heated to emit radiant energy. 
     As described above, as the internal space of the case  2  is divided by the barrier  20 , the heat transmission to the control unit is blocked, thereby preventing the control unit from malfunctioning or being damaged. 
     Furthermore, since the control unit is cooled by the air flowing by means of the fan  19 , the malfunctioning and damage of the control unit can be further prevented. 
     In addition, the barrier  20  blocks the air flowing toward the burner system by the fan  19  so as not to affect the flow of the air to the mixing pipe unit  6 . 
       FIG. 5  is a perspective view of a barrier according to the first embodiment. 
     Referring to  FIG. 5 , as described above, the barrier  20  functions to block the high temperature heat generated from the burned system transferred to the control unit controlling the operation of the burner system. 
     In more detail, the bather  20  includes a first barrier rib  201  for preventing the high temperature heat in the first space  2   a  from being transferred to the second space  2   b,  a second barrier rib  202  for preventing the high temperature heat in the first space  2   a  from moving upward, and a third barrier rib  203  for preventing the high temperature heat in the first space  2   a  from being transferred sideward. 
     The first barrier rib  201  is provided with through holes  205  and  206  through which the connection pipe  8   a  and the individual gas supply pipes  9  pass. A seating rib  204  is formed on a lower end of the first barrier rib  201  so that the barrier  20  can be securely disposed on the case  2 . 
     The second barrier rib  202  is provided with a switch hole  207  through which a portion of the switch  29  pass and a lamp hole  208  through which the lamp unit  18  pass. Contacting portions  209  are formed on both side surfaces of the second barrier ribs  202  so that the barrier  20  can closely contact the case  2  when the barrier  20  is disposed on the case  2 . 
     Meanwhile, the third barrier rib  203  extends from the first barrier rib  201  toward the second space  2   b.  At this point, the third barrier rib  203  extends to a location spaced apart from the front end  202   a  of the second barrier rib  202  by a predetermined distance so as not to interfere with the main gas supply pipe  8 . 
     Here, the through holes  205 ,  206 , and  207  function to allow the components disposed in the second space  2   b  to pass therethrough and to allow the air generated by the fan  19  to cool exposed portions to the first space  2   a.    
       FIG. 6  is an enlarged view of a portion A in  FIG. 4 . 
     Referring to  FIG. 6 , the spark plug  16  composed of a pair of ignition rods protrudes into the burner frame  11  to ignite the mixture gas. The protruding spark plug  16  is disposed above the glow plate  12 . 
     Accordingly, the mixture gas passing through the glow plate  12  is ignited by sparks generated by the spark plug  16 . 
     The spark plug  16  is designed such that the sparks are generated between the pair of the ignition rods by the current applied to one of the ignition rods. 
     Thermal detecting rods  22  are disposed between the spark plugs  16  to detect the heat generated from the glow plates  12 . The thermal detecting rod  22  is inserted from an outer side of the burner frames  11  into the burner frames  11  and disposed between the pair of the ignition rods. Here, the thermal detecting rods  22  are formed of metal having high thermal conductivity. 
     The thermal detecting rod  22  extends to the outer side of the burner frame  11  in a state where it is inserted in the burner frame  11 . A support  23  for coupling a thermostat  24  is installed on an extending end portion of the thermal detecting rod  22 . 
     Therefore, the heat generated from the glow plate  12  is transferred to the support  23  along the thermal detecting rod  22  and is subsequently transferred to the thermostat  24 . 
     The thermostat  24  has a first end connected to the power supply source and a second end connected to the lamp unit  18  and the fan  19 . When the heat detected by the thermostat  24  reaches a predetermined temperature, electric power is supplied to the lamp unit  18  and the fan  19 . 
     That is, when the heat is generated from the glow plate  12  by the operation of the burner system, the heat is transferred to the thermal detecting rod  22 . The thermostat  24  detects the heat transferred from the thermal detecting rod  22  to the support  23 . When the heat detected by the thermostat  24  is greater than or equal to the predetermined temperature, the electric power is supplied to the lamp unit  18  and the fan  19 . That is, when the heat above the predetermined temperature is transferred to the thermostat  24 , the lamp unit  18  and the fan  19  operated. 
     The thermal detecting rod  22  is grounded to the case  2 . That is, a ground wire  32  is connected to the thermal detecting rod  22  and is coupled to a grounding member  33  coupled to the case  2 . At this point, a screw may be used as the grounding member  33 . 
     Here, the current flows to one ignition rod to the other ignition rod. Since the thermal detecting rod  22  is disposed between the ignition rods, the current may partly flow to the thermal detecting rod  22 , for which the thermal detecting rod  22  is grounded to the case  2 . 
     In this embodiment, three thermal detecting rods  22  are provided and all of the thermal detecting rods  22  are commonly grounded to the grounding member  33 . Needless to say, the thermal detecting rods  22  may be individually grounded to different grounding members. 
     According to the position relationship between the thermal detecting rods  22  and the thermostat  24 , the following advantages may be obtained. 
     First, as the thermal detecting rod  22  inserted to the burner frame  11  so as to directly receive the heat generated from the glow plate  12 , the thermostat  24  can more sensitively and quickly detect the temperature variation of the glow plate  12 . 
     In addition, the thermostat  24  is designed to detect the temperature of the support  23  coupled to the thermal detecting rod  22  extending to the outer side of the burner frame  11 . The support  23  is cooled by the air around the burner system and thus the temperature of the support  23  is reduced to be lower than that of the thermal detecting rod  22 . Therefore, the temperature of the support  23  becomes lower than an internal temperature (about 300° C.)of the thermostat  24 , thereby preventing the thermostat  24  from being damaged. 
     Here, since the thermostat  24  is associated with the burner frame  11 , therefore, three thermostats  24  are provided in this embodiment. Therefore, the lamp unit  18  and the fan  19  may operate when at least one of the thermostats  24  detects the predetermined temperature. 
     Although the lamp unit  18  and the fan  19  operate in accordance with the temperature detected by the thermostats  24  in this embodiment, the lamp unit  18  and the fan  19  may be designed in response to the operation of the switches  29 . 
     That is, a micro-switch is provided under the switch  29 . When the switch  29  is turned on, the switch  29  presses a terminal of the micro-switch to operate the lamp unit  18  and the fan  19 . 
       FIG. 7  is a perspective view of the burner system according to the first embodiment. 
     Referring to  FIG. 7 , as described above, the mixing pipe unit  6  is coupled to a side of the burner pot  4 . A plurality of mixing pipes  61  is provided in the mixing pipe unit  6 . The burner pot  4  is provided with a plurality of openings  42  (see  FIG. 9 ) aligned with the respective mixing pipes  61 . A nozzle unit  5  is disposed to be spaced apart from the inlet of the mixing pipe unit  6 . 
     The nozzle unit  5  is formed in a straight shape since the inlet of the mixing pipe unit  6  is disposed inline. Therefore, the burner system can be designed to be more compact. 
     The mixing pipes  61  are horizontally arranged in parallel with each other in the mixing pipe unit  6 , an amount of air that is introduced together with the gas injected from the nozzle unit  5  and the air introduced can be increased. 
     That is, a large amount of the air is introduced together with the gas through the mixing pipes  61 . That is, the amount of the air is greater than a case where the gas is introduced through a single mixing pipe. 
     For example, when the gas is supplied through the single mixing pipe, a low pressure environment is formed around on the single mixing pipe. However, when the plurality of the mixing pipes is provided, the space through which the air can be introduced is increased and thus the total amount of the air introduced can be increased. 
     The mixing pipes  61  are arranged at an identical horizontal plane. Needless to say, although centers of the mixing pipes  61  may be slightly misaligned by a predetermined distance in a vertical direction, they are substantially arranged in parallel with each other. As the mixing pipes are arranged in parallel with each other, the mixture gas introduced into the burner pot  4  collides to generate turbulent current and thus the mixing rate between the gas and air is increased. Therefore, the combustion efficiency can be improved. Since levels where the mixing pipes  61  can be located are limited within a range where the openings  42  can be formed, the level variation of the mixing pipes  61  is limited within a predetermined range. 
     Meanwhile, the mixing pipes  61  may extend in an identical direction. That is, extending lines of the respective mixing pipes  61  may not meet each other so as to increase the turbulent current generation between the gases discharged from the mixing pipes  61  and simplify the manufacturing process of the mixing pipe unit  6 . In addition, the manufacturing process of the nozzle unit  5  aligned with the mixing pipe unit  6  becomes also simplified. 
     Further, the number of the mixing pipes  61  of the mixing pipe unit  6  is  5 . In this case, the mixing pipes  61  are equally spaced apart from each other within a diameter of the burner pot  4 . At this point, the mixing pipe  61  that is disposed on one outermost side is disposed corresponding to an end of the diameter of the burner pot  4 . In this case, since the turbulent current generation in the burner pot  4  is enhanced, the mixing efficiency of the mixture gas introduced into the burner pot  4  can be improved. 
       FIG. 8  is an exploded perspective view of the burner system of  FIG. 7 . 
     Referring to  FIG. 8 , the burner system includes the burner pot  4  provided with a circular depressed portion in which the air and gas introduced through the mixing pipe unit  6  can be sufficiently mixed with each other and the mixing pipe unit  6  coupled to a side of the burner pot  4 . The mixing pipe unit  6  includes the five mixing pipes  61 . 
     Therefore, when the mixing pipe unit  6  is coupled to the burner pot  4 , the five mixing pipes  61  are automatically aligned with the openings  42 . The distance between the inlets of the mixing pipes  61  and the nozzle unit  5  is not varied and thus the inflow amount of the air and gas is uniformed for each mixing pipe  61 . That is, since the mixing pipes  61  are integrally formed as the mixing pipe unit  6 , a lot of advantages can be obtained as compared with the case where the mixing pipes are individually mounted. 
     The advantages of the mixing pipe unit  6  can be more clearly identified when considering that the space where the low pressure can be formed by the injected gas is significantly reduced when centers of the outlet of the nozzle unit  5  is slightly misaligned with the inlet of the mixing pipe  61 . 
     As the mixing pipe unit  6  is coupled to the burner pot  4  with the above-described structure, the manufacturing and assembling process can be effectively realized. Furthermore, the mixing pipe unit  6  closely contacts the burner pot  4  and the manufacturing cost can be reduced. 
     The mixing pipes  61  may be coupled to the mixing pipe unit  6  in a state where they are supported by a jig. Alternatively, the mixing pipes  61  may be integrally formed with the mixing pipe unit  6 . 
     Since the inlets of the mixing pipes  61  can be aligned inline by the jig during the coupling of the mixing pipes  61  to the mixing pipe unit  6 , distances from the nozzle unit  5  to the inlets of the mixing pipes  61  can be uniformly maintained. 
       FIG. 9  is a sectional view taken along line I-I of  FIG. 1 , and  FIG. 10  is a perspective view of a sub-heating unit according to the first embodiment. 
     Referring to  FIGS. 9 and 10 , the burner frame  11  seats on the top of the burner pot  4 . The sub-heating unit  15  seats on the burner frame  11 . 
     In more detail, the sub-heating unit  15  is heated by the heat generated from the glow plate  12  to radiate the radiant energy. Therefore, the overall radiant energy of the heating cooling appliance increases. 
     Furthermore, the sub-heating unit  15  secondly combusts the mixture gas that is not combusted while passing through the glow plate  12 . 
     That is, the sub-heating unit  15  is provided in a path along which the mixture gas flows so that it can contact the mixture gas, thereby combusting the mixture gas. 
     That is, the sub-heating unit  15  generates a turbulent current in the combustion gas flowing rearward, thereby secondly combusting the non-combusted gas contained in the combustion gas. 
     The sub-heating unit  15  includes a heating element  156  that is heated by the heat generated from the glow plate  12  and a supporting member  152  that supports the heating element  156  such that the heating element  156  is spaced apart from the glow plate  12 . 
     In more detail, a seating portion  112  on which the supporting member  152  is disposed is formed around the opening of the burner frame  11 . The supporting member  152  is coupled to the burner frame  11  by a coupling member in a state where it is disposed on the seating portion  112 . To realize this, the supporting member  152  is provided with a through hole  155  through which the coupling member passes. Likewise, the burner frame  11  is also provided with a through hole through which the coupling member passes. 
     In order to prevent the supporting member from interfering with the spark plug  16  when the supporting member  152  is disposed on the burner frame  11 , the supporting member  152  has a cut-away portion corresponding to the spark plug  16 . 
     That is, the supporting member  152  is formed in a C-shape where a portion corresponding to the spark plug  16  is cut away. 
     The supporting member  152  is provided with a plurality of catching portions  153  extending upward from the supporting member  152  and coupled to the heating element  156 . 
     Here, the height of the catching portion  153  is set to disallow the heating element  156  to contact the glow plate  12  in a state where the sub-heating unit  15  is disposed on the burner frame  11 . 
     Further, the height of the catching portion  153  is set to disallow the heating element  156  to contact the glow plate  12  even when the heating element  156  expands by being heated. 
     However, the height of the catching portion  153  is set within a range where the heating element  156  can be heated by the heat generated from the glow plate  12 . 
     Here, one of the catching portions  153 , which is close to the exhaust portion  10 , is formed in a direction in which the combustion gas flows. 
     That is, in  FIG. 10 , the catching portion  13   a  close to the exhaust portion  10  may be formed in a width direction of the supporting member  152 . This is to prevent the generation of the flow resistance by the catching portion  153  during the exhaust process of the combustion gas. 
     Coupling grooves  154  are formed on both sides of each of the catching portions  153  to wound the heating element  156  around the catching portion  153 . That is, the heating element  156  is wound around the catching portion  153  in a state where it is inserted in the coupling grooves  154 . 
     Meanwhile, the heating elements  156  may be wires. When the heating element  156  is wound around at least a pair of the catching portions  153 , the heating element  156  maintains predetermined tension. 
     When viewed from a top, the sub-heating unit  15  has a mesh-shaped top. Therefore, it can be understood that a plurality of apertures through which the combustion gas can pass are formed in the sub-heating unit  15 . 
     Here, the arrangement of the heating elements  156  is not specifically limited. That is, the arrangement of the heating elements  156  can be varied in accordance with the catching portions  153  by which they are supported. For example, the heating elements  156  may be arranged in a star-shape or in a zigzag pattern. 
     Since the sub-heating unit  15  functions to secondly combust the mixture gas passing through the glow plate  12 , the glow plate  12  may be referred to as a first combustion unit and the sub-heating unit  15  may be referred to as a second combustion unit. 
     As described above, by winding the heating elements around the catching portions  153 , the sub-heating unit is completed. However, the present disclosure is not limited to this process. For example, after winding the heating elements  156  in a mesh pattern, the assembly of the heating elements  156  may be coupled to the supporting member  152 . 
       FIG. 11  is a graph comparing radiant energies in accordance with whether there is the sub-heating unit or not. 
     Referring to  FIG. 11 , a curve A shows a total radiant energy when only the glow plate is provided and a curve B shows a total radiant energy when the glow plate and the sub-heating unit are provided. 
     In the graph, a horizontal axis indicates a wavelength and a vertical axis indicates an intensity of the radiant energy. 
     As shown in the graph, it can be noted that, when the sub-heating unit is additional provided, the total radiant energy increases. For example, when the wavelength is about 2500 nm, the total radiant energy in a case where the sub-heating unit  15  is additional provided increases by 1.5 times as compared with a case where only the glow plate  12  is provided. 
     Further, the increase of the total radiant energy means the increase of the radiant energy radiated to an external side of the ceramic plate. Therefore, the user can easily identify the fact that the heating cooking appliance is operating by the radiant energy. 
     The following table 1 shows an amount of carbon monoxide and combustion efficiency in accordance with where the sub-heating unit is provided or not. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                   
                 Combustion 
               
               
                   
                 Carbon Monoxide (ppm) 
                 Efficiency (%) 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 No Sub-Heating Unit Is 
                 20 
                 38.60 
               
               
                 Provided 
               
               
                 Sub-Heating Unit Is 
                 15 
                 41.50 
               
               
                 Provided 
               
               
                   
               
            
           
         
       
     
     The results shown in the table 1 are obtained using an identical structure under an identical test condition. 
     Referring to Table 1, it can be noted that, when the sub-heating unit  15  is provided, an amount of the carbon monoxide is reduced. Here, the carbon monoxide is generated when the mixture gas is not perfectly combusted. 
     That is, by providing the sub-heating unit  15 , the mixture gas is secondly combusted and thus an amount of the carbon monoxide is reduced. 
     In addition, it can be also noted that, when the sub-heating unit  15  is provided, the combustion efficiency is improved as the mixture gas is secondly combusted. 
     Here, the amount of the carbon monoxide may be varied in accordance with a measuring location and a size of the burner system. However, when an identical burner system is used and measurement of the carbon monoxide is done at an identical location, the results shown in the table 1 can be obtained. 
       FIG. 12  is a top plane view of an inflowing path of air passing through the burner pot according to the first embodiment 
     Referring to  FIG. 12 , the mixture air is introduced to the burner systems disposed both sides of the heating cooling appliance in a rear-to-front direction and sufficiently mixed in the burner pots  4 . Next, the mixture air passages through the glow plate  12  and flows upward to be combusted. The mixture air is further combusted while passing through the sub-heating unit  15  and exhausted rearward. 
     As described above, since the turbulent current is sufficiently generated by the collision between the mixture gases in the burner pots  4 . Therefore, the flow rate component of the mixture gas frontward is eliminated and thus the air and gas is uniformed mixed in the burner pots  4 . Further, the mixture gas flows upward through the glow plate  13  and is combusted. The flow of the combustion gas is effectively realized. 
     Therefore, although the flow directions of the gas at the inlet side and the outlet side with reference to the burner systems are completely different from each other, the burner systems disposed at both sides of the heating cooking appliance allow the fluids to effectively flow without the flow resistance. 
     Second Embodiment 
     A second embodiment is identical to the first embodiment except for a structure of the spark plug. Therefore, like parts will not be described in detail in the second embodiment. 
       FIG. 13  is a view of a spark plug according to a second embodiment. 
     Referring to  FIG. 13 , according to a feature of this second embodiment, a heat detecting rod  28  functions as an ignition rod of the spark plug  26 . 
     In more detail, an ignition rod  27  protrudes toward the burner frame and a thermal detecting rod  27  for detecting a temperature of the glow plate  12  protrudes to a location spaced apart from the ignition rod  26 . 
     When the current is applied to the ignition rod  27 , the spark plug  26  ignites the mixture gas by generating sparks between the thermal detecting rod  28  and the ignition rod  27 . 
     The thermal ignition rod  28  is inserted in the burner frame  11  and extends to an external side of the burner frame  11 . A support  23  supporting a thermostat  24  is installed on an extending end of the thermal detecting rod  28 . 
     Here, since the thermal detecting rod  28  functions as one of the ignition rods, the thermal detecting rod  28  is grounded to the case  2 . Since the ground method of the thermal detecting rod  28  is identical to the first embodiment, detailed description will be omitted herein. 
     Third Embodiment 
     A third embodiment is identical to the first embodiment except for a structure of the heating elements. Therefore, like parts will not be described in detail in the third embodiment. 
       FIG. 14  is a perspective view of a sub-heating unit according to a third embodiment. 
     Referring to  FIG. 14 , a heating element  356  is formed in a coil shape and coupled to the supporting member  352 . The, coil-shaped heating element  356  is coupled to the supporting member  352  while having predetermined elastic force. 
     Therefore, after the heating elements  356  are heated, the heating elements  356  is not drooped but horizontally tensioned, thereby not contacting the glow plate  12 . 
     The heating element is formed in a coil shape to have the elastic force in this embodiment. However, the catching portions of the supporting member, to which the heating elements are coupled, may be designed having elastic force. 
     Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.