Patent Publication Number: US-8991385-B2

Title: Cooking appliance

Description:
TECHNICAL FIELD 
     Present embodiments relate to a cooking appliance. 
     BACKGROUND ART 
     A cooking appliance is a household appliance that uses gas, electricity, etc. to heat food. 
     In general, a cooking appliance that uses gas is provided with a plurality of burners on its top surface, and directly heats food by heating a vessel in which the food is stored with flames generated from combustion of gas at the burners. The flames generated from the cooking appliance are exposed to the outside. 
     DISCLOSURE OF INVENTION 
     Technical Problem 
     Embodiments provide a cooking appliance configured so that it can be used safely. 
     Embodiments also provide a cooking appliance with enhanced operational reliability. 
     Embodiments further provide a cooking appliance with a simplified structure. 
     Technical Solution 
     In one embodiment, a cooking appliance includes: a cabinet; a burner assembly provided within the cabinet, for combusting a gas mixture of air and gas; a nozzle assembly for supplying gas to the burner assembly; an exhaust passage in which combusted gas generated during combusting of the gas mixture flows; an intake passage in which air for mixing with the gas flows; and a top plate provided above the burner assembly, wherein combusted gas in the exhaust passage is exhausted to an outside through natural convection, and air outside the cabinet is drawn into the intake passage through natural convection. 
     In another embodiment, a cooking appliance using gas as fuel to generate heat, including: an intake through which outside air is drawn in; a combusting unit for combusting a gas mixture of the gas and the drawn in air; a gas supply unit for supplying gas to the combusting unit; an exhaust guide for guiding exhausting of combusted gas generated during combusting of the gas mixture in the combusting unit; and an exhaust provided proximate to the intake, for exhausting the combusted gas to the outside. 
     In a further embodiment, a cooking appliance built-in a cupboard, including: an intake for drawing in an outside fluid, the intake being located on an outwardly-exposed side of the cooking appliance in a state where the cooking appliance is installed on the cupboard; an intake passage in which fluid drawn in through the intake flows; a combustion portion for combusting a gas mixture of the drawn in fluid and gas; an exhaust for exhausting the combusted gas in the exhaust passage, the exhaust being located on an outwardly-exposed side of the cooking appliance in a state where the cooking appliance is installed on the cupboard. 
     Advantageous Effects 
     According to embodiments, through mixing, combusting, igniting, and exhausting gas mixture in a single burner assembly, a product with a simplified structure can be realized. 
     Also, because the length of a mixing tube, in which gas and air are mixed to form a gas mixture, is extended by a guide tube, efficiency of mixing the gas mixture can be retained while the size of a burner assembly can be reduced. 
     Further, because a barrier is provided to block the transfer of heat from combusted gas in an exhaust passage to an intake passage, gas can be stably supplied from a nozzle assembly to a burner assembly. 
     Additionally, because an intake and an exhaust are integrally formed, the aesthetics of the cooking appliance are improved, and its structure is simplified. 
     Moreover, because an intake passage and an exhaust passage extend in alignment, the lengths of the respective passages can be shortened, and space utilization within the cabinet can be improved. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of a cooking appliance in use according to present embodiments. 
         FIG. 2  is an exploded perspective view of a cooking appliance according to present embodiments. 
         FIG. 3  is an exploded perspective view of a burner assembly according to present embodiments. 
         FIG. 4  is a top perspective view of a burner assembly according to present embodiments. 
         FIG. 5  is a bottom perspective view of a burner assembly according to present embodiments. 
         FIG. 6  is a perspective view of a combustion obstructing member that configures a burner assembly according to present embodiments. 
         FIG. 7  is an exploded perspective view of a plug assembly that configures a burner assembly according to present embodiments. 
         FIG. 8  is an exploded perspective view of a thermocouple and protective member that configure a burner assembly according to present embodiments. 
         FIG. 9  is an exploded perspective view of a nozzle assembly according to present embodiments. 
         FIG. 10  is a perspective view of a valve assembly according to present embodiments. 
         FIG. 11  is a partial, vertical side sectional view of a cooking appliance according to present embodiments. 
         FIGS. 12 and 13  are views showing ON/OFF states of a valve assembly according to present embodiments. 
         FIG. 14  is a vertical sectional view showing airflow within a cooking appliance according to present embodiments. 
     
    
    
     MODE FOR THE INVENTION 
     Embodiments will be described in detail below, with reference to the drawings. 
       FIG. 1  is a perspective view of a cooking appliance in use according to present embodiments, and  FIG. 2  is an exploded perspective view of a cooking appliance according to present embodiments. 
     Referring to  FIGS. 1 and 2 , a cooking appliance according to present embodiments will be exemplarily described as a built-in appliance. 
     A cooking appliance  10  according to present embodiments is installed in a cupboard  1 . The cupboard  1  has an installation space  3  defined within, and the front and top of the cupboard  1  are open. The cooking appliance  10  is installed in the top opening of the cupboard  1 . 
     The cupboard  1  includes a pair of doors  5  and  7  that open and close the front opening of the cupboard  1 . 
     The cooking appliance  10  includes a cabinet  100  and a top cover  500  that define its exterior. The cabinet  100  is formed hexahedral in shape with the top open. The top cover  500  seals the open top of the cooking appliance  10 . 
     A plurality of cooling holes  110  is defined in the floor of the cabinet  100 . Air for cooling components provided within the cabinet  100  can flow through the cooling holes  110  into the cabinet  100  or be discharged to the outside. Also, a cooling passage P 3  (in  FIG. 14 ), through which air that passes through the cooling holes  110  flows, is provided within the cabinet  100 . 
     Below, a detailed description on the inner structure of the cooking appliance will be provided. 
     Referring to  FIG. 2 , the inside of the cabinet  100  is provided with a plurality of burner assemblies  200 ,  201 , and  202  for mixing gas and air and combusting the gas mixture, and a controller  400  for controlling the operation of a plurality of nozzle assemblies  300  for discharging gas and the plurality of burner assemblies  200 ,  201 , and  202 . 
     The plurality of burner assemblies  200 ,  201 , and  202  simultaneously combusts a gas mixture and guides the flow of combusted gas generated from the combusting of air and mixing gas that form the gas mixture. 
     The plurality of nozzle assemblies  300  supplies gas to the burner assemblies  200 ,  201 , and  202 . That is, each nozzle assembly  300  functions as a gas supply portion  300 . The controller  400  controls the operation of the burner assemblies  200 ,  201 , and  202  and the nozzle assemblies  300 . 
     The plurality of burner assemblies  200 ,  201 , and  202  includes 3 burner assemblies—that is, a first to third burner assembly  200 ,  201 , and  202 . 
     The first and second burner assemblies  200  and  201  are installed inside the cabinet  100  at the right and left, respectively, in the drawing. The third burner assembly  202  is installed between the first and second burner assemblies  200  and  201 , or, at the central portion within the cabinet  100 . The first to third burner assemblies  200 ,  201 , and  202  may be formed in different sizes. 
     While the present embodiment describes three burner assemblies provided in the cabinet  100 , there is no restriction to the number of burner assemblies, and at least one burner assembly may be provided in the cabinet  100 . 
     The first through third burner assemblies  200 ,  201 , and  202  are each connected at the rear to a connecting bracket  700  and fixed within the cabinet  100 . 
     The connecting bracket  700  includes, at the left and right thereof, an elongated rectangular fixing portion  710  (in  FIG. 11 ) and a flow guide  720  (in  FIG. 11 ) extending vertically from the rear of the fixing portion  710 . 
     The first to third burner assemblies  200 ,  201 , and  202  are fixed to the fixing portion  710 . The flow guide  720  partitions a passage for air drawn in and a passage for combusted gas through a flow guide unit  600  (to be described below), while also guiding the flow of the air and the combusted gas. That is, the flow guide  720  defines portions of an exhaust passage P 2  (in  FIG. 11 ) and an intake passage P 1  (in  FIG. 11 ). 
     An exhaust guide  730  (in  FIG. 11 ) is provided at the leading end of the flow guide  720 . The exhaust guide  730  extends in a forward and upward incline. 
     The exhaust guide  730  prevents gas exhausted through an exhaust  620  (in  FIG. 11 , described below) from moving toward an intake  610 . 
     The plurality of nozzle assemblies  300  includes three nozzle assemblies  300 . The nozzle assemblies  300  supply gas received from an external gas supply source to the first to third burner assemblies  200 ,  201 , and  202 . 
     The controller  400  is installed at the front of the first to third burner assemblies  200 ,  201 , and  202 —or, at the inner front portion of the cabinet  100 . The controller  400  includes three valve assemblies  410  for supplying and controlling the supplied amount of gas to the first to third burner assemblies  200 ,  201 , and  202 . A knob  420  is coupled to each valve assembly  410 , respectively. The knob  420  is a portion that a user grasps to control the valve assembly  410 . 
     A light emitter  430  is provided on each valve assembly  410 . The light emitter  430  is turned ON/OFF according to the operation of the valve assembly  410  to externally indicate whether the first to third burner assemblies  200 ,  201 , and  202  are ignited. 
     The top cover  500  includes a top frame  510  and a top plate  520 . 
     The front portion of the top frame  510  defines a plurality of knob through-holes  511  for the knob  420  of each valve assembly  410  to pass through. The front portion of the top frame  510  also defines a plurality of light emitter through-holes  513  for each of the light emitters  430  to pass through. 
     A plurality of openings  515  for intaking and exhausting air is defined at the rear portion of the top frame  510 . Each opening  515  functions as a passage for intaking external air to be supplied to the respective burner assemblies  200 ,  201 , and  202 , and exhausting combusted gas generated from the combustion of gas mixture. 
     Specifically, external air is drawn in and internal combusted gas is exhausted to the outside through a single opening  515  in present embodiments. Here, an intake passage P 1  (in  FIG. 11 ) for external air and an exhaust passage P 2  (in  FIG. 11 ) for combusted gas are partitioned within the cabinet  100  by the flow guide  730 , as described above. 
     The top plate  520  is installed on the top frame  510 . The top plate  520  performs the function of transferring heat (generated in the combusting of gas mixture at the respective burner assemblies  200 ,  201 , and  202 ) to food. 
     The top plate  520  may employ glass of a ceramic material as an example. Vessels containing food are placed on the top surface of the top plate  520 . The top plate  520  may have vessel seats (not shown) formed thereon to indicate where to position vessels on. 
     The flow guide unit  600  is provided at the rear of the upper surface of the top frame  510 . The flow guide unit  600  guides the intake of external air to be supplied to the respective burner assemblies  200 ,  201 , and  202 , and guides the exhausting of combusted gas from the respective burner assemblies  200 ,  201 , and  202 . 
     A detailed description of the structure of a burner assembly will be provided below. 
       FIG. 3  is an exploded perspective view of a burner assembly according to present embodiments,  FIG. 4  is a top perspective view of a burner assembly according to present embodiments, and  FIG. 5  is a bottom perspective view of a burner assembly according to present embodiments. 
     Referring to  FIGS. 3 to 5 , because the first to third burner assemblies  200 ,  201 , and  202  are the same in all other aspects but size, with respect to the first to third burner assemblies  200 ,  201 , and  202 , only a description of the first burner assembly  200  (hereinafter referred to as ‘burner assembly’ for descriptive convenience) will be provided. 
     The burner assembly  200  includes a combusting unit, an igniting unit, a mixing unit, and an exhaust guide unit. 
     The combusting unit is a region in which gas mixture is combusted, and includes a burner pot  210 , a pot cover  220 , and a combustion mat  230 . 
     The igniting unit generates a spark to combust gas mixture in the combusting unit. A plug assembly  240  is included in the igniting unit. 
     The mixing unit mixes gas and air and supplies the gas mixture. The mixing unit includes a tube assembly  250  and a guide tube  259 . 
     The exhaust guide unit guides the exhausting of combusted gas generated from combusting of the gas mixture in the combusting unit. The exhaust guide unit includes a burner frame  260 , an upper barrier  270 , and a lower barrier  280 . 
     In detail, the burner pot  210  is formed with an open top. Gas mixture is supplied into the burner pot  210 . 
     A sloped surface  211  is provided at the rear of the burner pot  210 . The sloped surface  211  is formed extending downward in a slope from the top of the burner pot  210 . 
     The sloped surface  211  defines a plurality of gas mixture supply holes  212 .  FIG. 3  shows five gas mixture supply holes  212  as an example. 
     The pot cover  220  seals the open top of the burner pot  210 . Also, a gas mixture guide hole  211  is defined in the pot cover  220  to guide gas mixture supplied into the burner pot  210  to the combustion mat  230 . Thus, because portions of the pot cover  220  other than the gas mixture guide hole  211  seal the top of the burner pot  210  to guide gas mixture to the combustion mat, these can be referred to as a guide member. 
     The pot cover  220  defines a mat seat  222 . The mat seat  222  of the pot cover  220  is defined by a portion of the pot cover  220  that is stepped downward. 
     The combustion mat  230  is a region where combustion of gas mixture actually occurs. The combustion mat  230  is seated on the mat seat  222 . Here, the top surface of the combustion mat  230  may be disposed on the same plane as the upper surface of the pot cover  220 . The combustion mat  230  may be formed of a ceramic material. 
     A combustion obstructing member  231  is provided within the burner pot  210 . The combustion obstructing member  231  obstructs (or reduces) combustion of gas mixture at the central portion of the combustion mat  230 . 
     Specifically, the combustion obstructing member  231  prevents damage to the top plate  520  and/or a vessel from heat being concentrated in the space between the top plate  520  and the undersurface of the vessel (when cooking food inside a vessel such as a ceramic bowl that curves upward from its bottom). 
     The combustion obstructing member  231  is seated on the burner pot  210 , and is attached to the center of the bottom surface of the combustion mat  230  to prevent combustion of gas mixture at the central portion of the combustion mat  230 , or is proximate to the center of the bottom surface of the combustion mat  230  to reduce combustion of gas mixture. 
     The tube assembly  250  includes a plurality of mixing tubes  251 , a plurality of air barriers  252 , and a sealing portion  253 . 
     The mixing tube  251  is where mixing of gas and air actually occurs, and also guides the gas mixture to the burner pot  210 . The mixing tube  251  is formed in a cylindrical shape having a diameter corresponding to the diameter of the gas mixture supply hole  212  when parallelly projected. The front of each mixing tube  251  is sloped corresponding to the slope of the sloped surface  211 . 
     The plurality of air barriers  252  is provided laterally elongated at the rear portions of the mixing tubes  251 . The plurality of air barriers  252  is separated from front-to-rear. 
     The air barriers  252  prevent air that is drawn into the cabinet  100  through the cooling holes  110  from flowing toward the nozzle assembly  300 . 
     In detail, with reference to  FIG. 1 , when the doors  5  and  7  of the cupboard  1  are being open and shut, a large volume of air may enter the installation space  3 . The air that enters the installation space  3  enters into the cabinet  100  through the cooling holes  110 . If the air that enters the cabinet  100  flows toward the nozzle assembly  300 , the air around the nozzle assembly  300  and the air discharged from the nozzle assembly  300  impede flow to the respective mixing tubes  251 . 
     According to present embodiments, however, the air entering into the cabinet  100  through the cooling holes  110  can be blocked from flowing toward the nozzle assembly  300  by means of the air barrier  252 . 
     Also, the plurality of mixing tubes  251  is coupled to the air barriers  252 . The sealing portion  253  is connected to the front end of each mixing tube  251 . 
     The sealing portion  253  has the same sloped angle as the sloped surface  211  so that it can be sealed with the sloped surface  211 . Accordingly, leaking of gas mixture supplied from the respective mixing tubes  251  to the burner pot  210  can be prevented. 
     While pressed against the sloped surface  211 , the sealing portion  253  is fastened thereto by means of a fastening member (not shown). 
     The tube assembly  250  includes a plurality of fastening ribs  244  to fasten it to the nozzle assembly  300 . The plurality of fastening ribs  244  is formed on the air barrier  252 . A fastening hole  255  is defined in each of the fastening ribs  254 . Also, a guide projection  256  is formed on the upper surface of each fastening rib  254  to couple with the nozzle assembly  300 . 
     While not shown, a gasket may be provided at the region where the burner pot  210  and the tube assembly  250  are pressed together—that is, between the sloped surface  211  and the sealing portion  253 . 
     The gasket prevents the gas mixture supplied from the tube assembly  250  to the burner assembly  200  from leaking through gaps. 
     The guide tube  259  is disposed within the burner pot  210 . The guide tube  259  extends the length of the mixing tube  251  to increase mixing efficiency of gas and air. 
     That is, by increasing the physical distance over which gas and air to be mixed can flow, the guide tube  259  increases the mixing efficiency of gas and air. 
     The rear of the guide tube  259  is formed of a sloped angle corresponding to that of the sloped surface  211 . In order to prevent the guide tube  259  from impeding combustion at the combustion mat  230 , the guide tube  259  may be disposed not to vertically overlap the combustion mat  230 . 
     The burner frame  260  is disposed above the combustion mat  230 . 
     The burner frame  260  includes a first burner frame  261  and a second burner frame  265 . The first burner frame  261  guides combusted gas generated from combusting of gas mixture at the combustion mat  230  to the second burner frame  265 . The first burner frame  261  is fixed to the pot cover  220 . Therefore, the first burner frame  261  and the pot cover  220  can fix the position of the combustion mat  230 . The second burner frame  265  guides combusted gas to the flow guide unit  600 . 
     A heat transfer hole  262  is defined in the central portion of the first burner frame  261  in order to facilitate transfer of heat generated during combustion of gas mixture at the combustion mat  230  to the top plate  520 . The heat transfer hole  262  may be formed in a circular shape corresponding to the gas mixture guide hole  221 . 
     The first burner frame  261  includes a guide rib  263  and a plate supporting rib  264 . The guide rib  263  does not discharge combusted gas generated during combustion of gas mixture at the combustion mat  230 , but guides the combusted gas to the second burner frame  265 . 
     Also, the guide rib  263  does not diffuse heat generated during combustion of gas mixture at the combustion mat  230 , but concentrates the heat toward the top plate  520 . 
     The guide rib  263  extends from all bottom edges of the first burner frame  261 , with the exception of the rear of the first burner frame  261 . 
     The plate supporting rib  264  supports the undersurface of the top plate  520 . The plate supporting rib  264  is formed extending outward from the guide rib  263  toward the outside of the first burner frame  261 . 
     The second burner frame  265  is connected to the first burner frame  261 . The second burner frame  265  may be integrally formed with the first burner frame  261 , or may be formed separately from and coupled to the first burner frame  261 . 
     The second burner frame  265  includes a guide rib  266  and a plate supporting rib  267 . The guide rib  266  extends upward the same height as the guide rib  263  of the first burner frame  261  at either side of the second burner frame  265 . 
     The plate supporting rib  267  is formed extending to either side from the upper ends of each guide rib  266 . Also, the plate supporting rib  267  supports the top plate  520 . 
     The guide rib  266  is provided with a partitioning rib  268  at a rear thereof. The partitioning rib  268  extends upward from the guide rib  266 . 
     The partitioning rib  268  prevents combusted gas generated in the respective burner assemblies  200 ,  201 , and  202  from mixing inside the cabinet. 
     A plurality of hot wires  235  is provided above the combustion mat  230 . The hot wires  235  allow easy discernment from the outside of whether gas mixture is being combusted in the burner assembly  200 . 
     When the hot wires  235  change color from being raised in temperature by combustion of gas mixture at the combustion mat  230 , a user is able to discern that gas mixture is being combusted in the burner assembly  200 . 
     Both ends of the hot wire  235  are fixed to the first burner frame  261 . The hot wire  235  is extended and fixed to the first burner frame  261 . This is to prevent the hot wire  235  from being extended by heat and contacting the combustion mat  230 . 
     An intake passage P 1  (in  FIG. 11 ) is provided below the burner frame  260  inside the cabinet  110 . Air to be supplied to the burner assembly flows in the intake passage P 1 . 
     In present embodiments, the intake passage P 1  is actually defined by the floor of the cabinet  100  and the lower surface of the second burner frame  265 . 
     The upper barrier  270  is seated on the second burner frame  265  and disposed between the top plate  520  and the second burner frame  265 . The upper barrier  270  is formed in a U-shape. 
     In present embodiments, the second burner frame  265  and the upper barrier  270  define the exhaust passage P 2  through which combusted gas flows. However, the upper barrier  270  may be removed, and the exhaust passage P 2  may be defined by the second burner frame  265  and the top plate  520 . 
     The upper barrier  270  transfers a portion of heat from combusted gas flowing through the exhaust passage P 2 —specifically, an amount of heat sufficient to warm food—to the top plate  520 . 
     Accordingly, the top plate  520  above the exhaust passage P 2  defines a warm zone that can warm food with heat from combusted gas flowing through the exhaust passage P 2 . 
     The lower barrier  280  is coupled at the bottom of the second burner frame  265 . A portion of the lower barrier  280  is disposed between the second burner frame  265  and the tube assembly  250 , and another portion is disposed between the second burner frame  265  and the nozzle assembly  300 . 
     The lower barrier  280  prevents heat from combusted gas flowing through the exhaust passage P 2  from being transferred to the tube assembly  250  and the nozzle assembly  300 . The lower barrier  280  is formed in a U-shape, with either side surface pressed against the guide rib  266  of the second burner frame  265 . 
     Gaskets G 1  and G 2  are provided between the pot cover  220  and the first burner frame  261 , and the second burner frame  265  and the lower barrier  280 , respectively. 
     The gasket G 1  prevents gas leakage through gaps between the pot cover  220  and the first burner frame  261 . 
     The gasket G 2  prevents heat exchange between the second burner frame  265  and the lower barrier  280 . 
     With the burner pot  210 , pot cover  220 , combustion mat  230 , gasket G 1 , and burner frame  260  stacked vertically, the burner pot  210  and the burner frame  260  are fixed with a fastening member (not shown), to assemble the burner assembly  200 . 
     Here, the upper barrier  270  is seated on the top surface of the burner frame  260 , and the lower barrier  280  is fixed to the lower surface of the burner frame  260  by means of a fastening member (not shown). 
       FIG. 6  is a perspective view of a combustion obstructing member that configures a burner assembly according to present embodiments. 
     Referring to  FIGS. 3 and 6 , the combustion obstructing member  231  includes an obstructing portion  232 , a plurality of supporting portions  233 , and a plurality of fixing portions  234 . 
     The obstructing portion  232  is formed in the shape of a round plate. The obstructing portion  232  is pressed against the central portion on the lower surface of the combustion mat  230 , or is separated a predetermined distance from the central portion on the lower surface of the combustion mat  230 . 
     Each of the plurality of supporting portions  233  extends downward from the obstructing portion  232  to support the obstructing portion  232  at a predetermined height from the floor of the burner pot  210 . That is, the obstructing portion is separated from the floor of the burner pot  210 . Thus, the flow of gas mixture supplied into the burner pot  210  is unimpeded by the combustion obstructing member  231 . 
     The fixing portions  234  extend in mutually divergent directions at the bottoms of the supporting portions  233 . The respective fixing portions  234  are fixed to the floor of the burner pot  210  by means of separate fastening members, welding, etc. 
       FIG. 7  is an exploded perspective view of a plug assembly that configures a burner assembly according to present embodiments. 
     Referring to  FIGS. 3 and 7 , the plug assembly  240  includes a spark plug  241 , a plug target  242 , and a plug holder  243 . The spark plug  241  and the plug target  242  generate a spark for igniting the gas mixture. 
     The plug target  242  is formed of metal, and is spaced a predetermined gap from the spark plug  241 . When power is applied to the spark plug  241 , a spark is generated between the spark plug  241  and the plug target  242 . 
     The spark plug  241  and the plug target  242  are installed on the plug holder  243 . The plug holder  243  is fixed to the first burner frame  261 . The spark plug  241  and the plug target  242  are mounted on the plug holder  243  and are passed through the first burner frame  261  to be disposed above the combustion mat  230 . 
     A holder body  244  and a holder cover  247  are included on the plug holder  243 . The holder body  244  forms a plug seat  245  in which a side of the spark plug  241  is seated, and a target insertion hole  246  in which an end of the plug target  242  is inserted. 
     With the spark plug  241  seated in the plug seat  245  and the plug target  242  inserted in the target insertion hole  246 , the holder cover  247  is coupled to the top of the holder body  244 . 
     The plug holder  243  is coupled to the first burner frame  261  by means of a fastening member. In present embodiments, the plug holder  243  is formed of metal. Accordingly, the plug holder  243  in which the plug target  242  is inserted is fixed to the first burner frame  261 , so that the plug assembly  240  can be grounded without the use of a separate ground wire. 
       FIG. 8  is an exploded perspective view of a thermocouple and protective member that configure a burner assembly according to present embodiments. 
     Referring to  FIGS. 3 and 8 , a thermocouple  291  is installed on the first burner frame  261 . 
     The thermocouple  291  is passed through the first burner frame  261 , and has a portion thereof disposed within the first burner frame  261  and another portion disposed outside the first burner frame  261 . 
     While gas mixture is being combusted on the combustion mat  230 , the temperature difference between the portion of the thermocouple  291  disposed within the first burner frame  261  and the portion disposed outside the first burner frame  261  generates a predetermined electromotive force. 
     Depending on the presence of electromotive force in the thermocouple  291 , the valve assembly  410  that supplies gas is maintained in an open state, or the valve assembly  410  that is open is closed. 
     The thermocouple  291  is enclosed by a protective member  293 . The protective member  293  is for protecting the portion of the thermocouple  291  disposed within the first burner frame  261 . That is, the protective member  293  prevents damage to the thermocouple  291  from heat generated during combustion of combustion gas at the combustion mat  230 . In present embodiments, in order to electrically insulate the thermocouple  291 , an insulator formed of ceramic material may be used for the protective member  293 . 
     The protective member  293  is formed in a hexahedral shape, and includes a through-hole  294  through which the thermocouple  291  is passed. One end of the protective member  293  is formed in an approximately cylindrical shape. The one end of the protective member  293  with the cylindrical shape has a bracket  295  (that fixes to the first burner frame  261 ) seated thereon. 
       FIG. 9  is an exploded perspective view of a nozzle assembly according to present embodiments. 
     Referring to  FIG. 9 , the nozzle assemblies  300  according to present embodiments perform the function of supplying gas to each burner assembly  200 ,  201 , and  202 , respectively. In present embodiments, while the three nozzle assemblies  300  are provided in triplicate, because the structures of the respective nozzle assemblies  300  are all the same, description will be provided below of only one nozzle assembly  300 . 
     The nozzle assembly  300  includes a nozzle body  310 , a nozzle cover  320 , a plurality of discharge nozzles  330 , and a nozzle gasket  340 . 
     The nozzle body  310  defines the exterior of the nozzle assembly  300 . The nozzle body  310  has an open top. The nozzle body  310  includes a supply hole  311  to which an end of a gas hose (not shown) for connecting to the valve assembly  410  is connected, and a plurality of discharge holes  312  that couples with the discharge nozzles  330 . The supply hole  311  is defined in one end of the nozzle body  310 . The plurality of discharge holes  312  is formed in the front surface of the nozzle body  310  facing the rear of the tube assembly  250 . 
     Screw threads are defined in the inner peripheries of the supply hole  311  and the plurality of discharge holes  312 , for coupling with the gas hose and the discharge nozzles  330 . 
     In order to minimize the quantity of material and the number of processes used for fabricating the nozzle body  310 , the nozzle body  310  is formed through die casting aluminum, and the supply hole  311  and the discharge holes  312  are defined through tapping. 
     The nozzle cover  320  seals the open upper surface of the nozzle body  310 . Thus, a predetermined space is formed between the nozzle body  310  and the nozzle cover  320 . That is, the nozzle body  310  and the nozzle cover  320  define a gas receiving space. Also, the space  316  communicates with the supply hole  311  and the discharge hole  312 . 
     Each of the discharge nozzles  330  discharges gas from the gas flow space  316  at high pressure toward the mixing tube  251 . The discharge nozzles  330  are coupled to the discharge holes  312 , respectively. In order to introduce air around the mixing tube  251  into the mixing tube together with gas when gas that is discharged from the discharge nozzle  330  flows to the mixing tube, the discharge nozzle  330  is separated from the rear of the mixing tube  251  when coupled to the discharge hole  312 . 
     Screw threads are formed on the outer periphery of the discharge nozzle  330  to correspond to the screw threads of the discharge hole  312 . 
     A plurality of fastening ribs  313  is formed on the first nozzle body  310 . The fastening ribs extend forward from the front of the nozzle body  310 —that is, toward the tube assembly  250 . A through-hole  314  through which a fastening member (not shown) passes, and a guide hole  315  in which a guide projection  256  of the tube assembly  250  is inserted are defined in the fastening rib  313 . 
     Accordingly, with the guide projection  256  inserted in the guide hole  315 , a fastening member passed through the through-hole  314  is fastened to the fastening hole  255 , in order to couple the tube assembly  250  and the nozzle assembly  300 . 
     The nozzle gasket  340  is disposed between the nozzle body  310  and the nozzle cover  320 . The nozzle gasket  340  seals the gap between the nozzle body  310  and the nozzle cover  320 . That is, the nozzle gasket  340  prevents gas leaking through the gap between the nozzle body  310  and the nozzle cover  320 . 
     Also, an identifying rib  341  is formed on the nozzle gasket  340 . The identifying rib  341  allows a user to easily discern whether the nozzle gasket  340  is installed. With the nozzle gasket  340  installed between the first nozzle body  310  and the nozzle cover  320 , the identifying rib  341  is exposed outside the nozzle assembly  300 . When the identifying rib  341  is exposed outside the nozzle assembly  300 , a user can discern that the nozzle gasket  340  has been installed in the nozzle assembly  300 . 
       FIG. 10  is a perspective view of a valve assembly according to present embodiments. 
     Referring to  FIG. 10 , the valve assembly  410  selectively supplies gas to the nozzle assembly  300  and the light emitter  430  is simultaneously turned ON/OFF. 
     The valve assembly  410  includes a valve  411 , a first drive lever  415  and a second drive lever  416 , an ON/OFF switch  417 , and an ignition switch  418 . 
     The valve  411  controls whether gas transferred through the nozzle assembly  300  is supplied and controls the supplied volume of gas. The valve  411  includes a valve body  412 , a valve shaft  413 , and a tensile member  414 . 
     The valve body  412  includes a gas passage (not shown), and a pair of connecting holes (not shown) communicating with the gas passage. One of the pair of connecting holes has a gas hose (not shown) connected thereto for connecting to an external gas supply source (not shown). The other of the pair of connecting holes has a gas hose (not shown) connected thereto for connecting to the nozzle assembly  300 . 
     Also, a plug (not shown) is provided within the valve body  412  to control the closed or opened degree of the valve  411 . The controlling structure that controls the amount by which the valve  411  is closed and opened with the plug is well known, and thus, a detailed description thereof will not be provided. 
     The valve shaft  413  is rotatably installed in the valve body  412 . A knob  420  and a plug are coupled at either end of the valve shaft  413 , respectively. Thus, when a user presses the knob  420 , the plug moves in a lengthwise direction of the valve shaft  413  to open the valve  411 . Also, when a user rotates the knob  420  about the valve shaft  413  in a clockwise or counterclockwise direction (in the drawings), the plug controls the volume of gas that flows within the valve body  412 . 
     In present embodiments, when the knob  420  is rotated clockwise, the plug increases the opened degree of the valve  411 , and when the knob  420  is rotated counterclockwise, the plug decreases the opened degree of the valve  411 . 
     The tensile member  414  imparts biasing force to the valve shaft  413  to move the plug in a closing direction of the valve  411 . 
     Accordingly, when a user removes pressing force on the knob  420  in the lengthwise direction of the valve shaft  413 , the valve shaft  413  is moved by means of the biasing force of the tensile member  414  so that the valve  411  is closed by the plug. 
     The first drive lever  415  and the second drive lever  416  rotate in relation to the rotation of the valve shaft  413 . The first drive lever  415  turns the ON/OFF switch  417  ON/OFF, and the second drive lever  416  turns the ignition switch  418  ON/OFF. 
     In the present embodiment, when the valve shaft  413  in the drawing is rotated clockwise, the plug opens the passage in the valve body  412  to maximum, and the ON/OFF switch  417  is turned OFF, and the ignition switch  418  is turned ON. 
     The ON/OFF switch  417  generates an electrical signal for switching of the light emitter  430 . The ON/OFF switch  417  includes a moving terminal  417   a  and a fixed terminal  417   b . Accordingly, when the moving terminal  417   a  and the fixed terminal  417   b  are separated and OFF, the light emitter  430  is ON. Conversely, when the first drive lever  415  puts the moving terminal  417   a  in contact with the fixed terminal  417   b  to be ON, the light emitter  430  is turned OFF. 
     The ignition switch  418  generates an electrical signal for emitting a spark from the spark plug  241 . The ignition switch  418  includes a moving terminal  418   a  and a fixed terminal  418   b.    
     Accordingly, when the second drive lever  416  puts the moving terminal  418   a  and the fixed terminal  418   b  in contact to be ON, current is supplied to the spark plug  241  in order to generate a spark to combust gas mixture supplied to the burner assembly  200 . 
       FIG. 11  is a partial, vertical side sectional view of a cooking appliance according to present embodiments. 
     Referring to  FIGS. 2 and 11 , the flow guide unit  600  is formed laterally elongated. 
     The flow guide unit  600  includes a plurality of intakes  610  for intaking air from the outside, and a plurality of exhausts  620  for exhausting combusted gas to the outside. 
     The intakes  610  are disposed at the rear of the exhausts  620 . Specifically, the intakes  610  are defined at the rear of the flow guide unit  600 , and the exhausts  620  are provided at the top, front portion of the flow guide unit  600 . 
     This separation of the intakes  610  and the exhausts  620  is physically achieved by the flow guide  720  of the connecting bracket  700 . 
     Each of the intakes  610  communicates with the intake passage P 1 , and each of the exhausts  620  communicate with the exhaust passage P 2 . 
     Also, an auxiliary inlet hole  630  is defined at the rear upper end of the flow guide unit  600 . Thus, external air passes through the intake  610  and the auxiliary air inlet hole  630  into the intake passage P 1 . 
       FIGS. 12 and 13  are views showing ON/OFF states of a valve assembly according to present embodiments, and  FIG. 14  is a vertical sectional view showing airflow within a cooking appliance according to present embodiments. 
     Referring to  FIGS. 1 to 14 , with the valve  411  of the valve assembly  410  closed, the ON/OFF switch  417  is turned ON by the first drive lever  415 . The ignition switch  418 , on the other hand, is turned OFF. 
     Thus, gas is not supplied to the nozzle assembly  300 , and the spark plug  241  does not generate a spark, while the light emitter  430  is retained in an OFF state. 
     As shown in  FIG. 12 , when a user rotates the knob  420  clockwise (in the drawings) to open the valve  411 , the valve shaft  413  coupled to the knob  420  is also turned clockwise (in the drawings). Accordingly, the valve  411  is opened to begin supplying gas to the nozzle assembly  300 . 
     The gas supplied to the nozzle assembly  300  mixes with air in the intake passage P 1  to yield a gas mixture that is supplied through the tube assembly  250  to the burner assembly  200 . 
     When the knob  420  is continuously turned clockwise (in the drawings), the valve shaft  413  is also continuously rotated clockwise. Then, when the opened degree of the valve  411  reaches its maximum point through clockwise rotation of the valve shaft  413 , the second drive lever  416  turns the ignition switch  418  ON. 
     Thus, the gas mixture supplied to the first burner assembly  200  is ignited and combusted by means of a spark generated through a current supplied to the spark plug  241 . 
     Also, when the valve  411  is maximally opened, the ON/OFF switch  417  is turned ON. Hence, the light emitter  430  is lit to enable a user to discern that combustion of gas mixture is occurring in the burner assembly  200 . 
     When the gas mixture supplied to the burner assembly  200  is combusted through the spark generated by the spark plug  241 , the knob  420  is rotated counterclockwise to control the opened degree of the valve  411 . 
     Referring to  FIG. 14 , heat generated from combustion of gas mixture at the combustion mat  230  is transferred through the top plate  520  to a vessel seated atop the top plate  520 . The vessel is thus heated to physically cook food contained in the vessel. 
     The hot combusted gas generated from the combustion of gas mixture at the combustion mat  230  flows through the exhaust passage P 2 . The combusted gas is exhausted through the exhausts  620  of the flow guide unit  600  communicating with the exhaust passage P 2 . The guide portion  720  of the connecting bracket  700  guides combusted gas exhausted through the exhausts  620  in a forward direction. Therefore, the combusted gas exhausted through the exhausts  620  is prevented from contaminating wall surfaces at the rear—that is—kitchen wall surfaces. 
     Here, because the combusted gas is of higher temperature and pressure than air outside the cooking appliance, it is exhausted by means of convection through the exhausts  620  to the outside of the cooking appliance at which there is low pressure (atmospheric pressure). 
     Conversely, gas discharged through the discharge nozzle  330  flows into the tube assembly  250  at high velocity. Here, because gas that passes the mixing tube  251  of the tube assembly  250  is high in velocity, the pressure of the space around the air inlet holes of the flow guide unit  600  is lower than atmospheric pressure (pressure outside the cooking appliance) due to Bernouilli&#39;s principle. Thus, air outside the cooking appliance  10  flows into the intake passage P 1  through the intake  610 . 
     The intake passage P 1  and the exhaust passage P 2  extend parallelly to each other. Also, a portion of the exhaust passage P 2  is disposed above the intake passage P 1 . 
     Further, as shown in  FIG. 14 , outside air is drawn in and combusted gas is discharged at the flow guide unit  600 , so that the direction in which air flows in the intake passage is opposite the direction of combusted gas flow in the exhaust passage. 
     The upper barrier  270  transfers a portion of heat from combusted gas flowing through the exhaust passage P 2  to the top plate  520 . Therefore, food can be warmed in the warm zone of the top plate  520  correspondingly disposed above the exhaust passage P 2 . Also, the heat from the combusted gas flowing in the exhaust passage P 2  is prevented from being transferred to the tube assembly  250  by means of the lower barrier  280 . 
     The air within the installation space  3  of the cupboard  1  in which the cabinet  100  is installed passes through the cooling holes  110  of the cabinet  100  into the cabinet  100  and flows through the cooling passage P 3 . 
     Air drawn into the cabinet  100  from the air that circulates in the cooling passage P 3  cools various components configuring the controller  400 , and is discharged through the cooling holes  110 . 
     The cooking appliance described in above embodiments is one that is used installed in a cupboard. However, this does not have to be the case, and the employed cooking appliance may be a self-standing appliance. 
     Also, in above embodiments, there is no provision of a separate cooling fan installed inside the cabinet to cool electrical components including the controller. For the sake of more efficient cooling of electrical components, however, a cooling fan may be provided.