Abstract:
A cooking appliance includes a cavity to define a cooking chamber, a door to open and close the cooking chamber, a partition plate to partition the cavity into a first chamber and a second chamber, the partition plate facing the door in the closed state, wherein the door closes the first chamber, a burner provided in the second chamber to burn gas, thereby generating flame, and a fan provided in the second chamber to allow heated air to flow.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims priority under 35 U.S.C. 119 and 35 U.S.C. 365 to Korean Patent Application No. 10-2014-0039838 (filed on Apr. 3, 2014), which is hereby incorporated by reference in its entirety. 
       BACKGROUND 
       [0002]    The present disclosure relates to a cooking appliance, a burner, and a burner assembly. 
         [0003]    Cooking appliances are devices for cooking foods by using heat of a heating source. Cooking appliances, for example, an oven range includes an oven chamber in which foods are cooked and a burner that burns a gas to cook the foods within the oven chamber. 
       SUMMARY 
       [0004]    Embodiments provide a cooking appliance, a burner, and a burner assembly. 
         [0005]    In one embodiment, a cooking appliance includes: a cavity to define a cooking chamber; a door to open and close the cooking chamber; a partition plate to partition the cavity into a first chamber and a second chamber, the partition plate facing the door in the closed state, wherein the door closes the first chamber; a burner provided in the second chamber to burn a gas, thereby generating flame; and a fan provided in the second chamber to allow heated air to flow. 
         [0006]    In another embodiment, a burner includes: a burner tube having both ends that are spaced apart from each other, the burner tube having an inner periphery and an outer periphery; a plurality of gas outlet holes defined on the inner periphery of the burner tube; and a supply part disposed on a first end of both ends of the burner tube to supply a gas. 
         [0007]    In further another embodiment, a burner assembly includes: a burner having an inner periphery and an outer periphery, wherein a plurality of gas outlet holes are defined on the inner periphery; a burner cover to define a combustion chamber in which the burner is accommodated; and a fan disposed outside of the combustion chamber. 
         [0008]    The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a perspective view of a cooking appliance according to a first embodiment. 
           [0010]      FIG. 2  is a front view of a state in which a door is removed from the cooking appliance according to the first embodiment. 
           [0011]      FIG. 3  is a view of a state in which a burner assembly is removed in  FIG. 2 . 
           [0012]      FIG. 4  is an exploded perspective view of the burner assembly according to the first embodiment. 
           [0013]      FIG. 5  is a perspective view of a burner device according to the first embodiment. 
           [0014]      FIG. 6  is a perspective view illustrating a first cover of the burner device of  FIG. 5 . 
           [0015]      FIG. 7  is a cross-sectional view taken along line A-A′ of  FIG. 6 . 
           [0016]      FIG. 8  is a perspective view illustrating a second cover of the burner device of  FIG. 5 . 
           [0017]      FIG. 9  is a cross-sectional view taken along line B-B′ of  FIG. 8 . 
           [0018]      FIGS. 10 and 11  are perspective views of a burner according to the first embodiment. 
           [0019]      FIG. 12  is a view of a state in which the burner of  FIG. 10  is linearly spread. 
           [0020]      FIG. 13  is a vertical cross-sectional view of a state in which the burner assembly is installed in a cavity according to the first embodiment. 
           [0021]      FIG. 14  is a perspective view of a cooking appliance according to a second embodiment. 
           [0022]      FIG. 15  is a front view of the cooking appliance in which a second door is removed in  FIG. 14 . 
           [0023]      FIG. 16  is a perspective view of a burner according to a third embodiment. 
           [0024]      FIG. 17  is a perspective view of a burner according to a fourth embodiment. 
           [0025]      FIG. 18  is a perspective view of a burner according to a fifth embodiment. 
           [0026]      FIG. 19  is a perspective view of a burner according to a sixth embodiment. 
           [0027]      FIG. 20  is a perspective view of a burner according to a seventh embodiment. 
           [0028]      FIG. 21  is a perspective view of a burner according to an eighth embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0029]    Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. 
         [0030]    In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific preferred embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is understood that other embodiments may be utilized and that logical structural, mechanical, electrical, and chemical changes may be made without departing from the spirit or scope of the invention. To avoid detail not necessary to enable those skilled in the art to practice the invention, the description may omit certain information known to those skilled in the art. The following detailed description is, therefore, not to be taken in a limiting sense. 
         [0031]    Also, in the description of embodiments, terms such as first, second, A, B, (a), (b) or the like may be used herein when describing components of the present application. Each of these terminologies is not used to define an essence, order or sequence of a corresponding component but used merely to distinguish the corresponding component from other component(s). It should be noted that if it is described in the specification that one component is “connected,” “coupled” or “joined” to another component, the former may be directly “connected,” “coupled,” and “joined” to the latter or “connected”, “coupled”, and “joined” to the latter via another component. 
         [0032]      FIG. 1  is a perspective view of a cooking appliance according to a first embodiment, and  FIG. 2  is a front view of a state in which a door is removed from the cooking appliance according to the first embodiment. 
         [0033]    Referring to  FIGS. 1 and 2 , a cooking appliance  1  according to a first embodiment includes an oven unit  20 , a cook-top unit  60 , a drawer unit  40 , and a control unit  50 . Also, the cooking appliance  1  includes an outer case  11 . The outer case  11  may cover both side surfaces and rear surface of the oven unit  20  and the drawer unit  40 . 
         [0034]    However, according to a kind of cooking appliance  1 , the cook-top unit  60  and the drawer unit  40  may be omitted. 
         [0035]    The cook-top unit  60 , the oven unit  20 , and the drawer unit  40  may be disposed on an upper portion, a central portion, and a lower portion of the cooking appliance  1 , respectively. Also, the control unit  50  is disposed on a rear end of a top surface of the cooking appliance  1 . 
         [0036]    The cook-top unit  60  may include a plurality of cook-top burners  61 . The cook-top burner  61  may heat a container in which food is contained or directly heat food by using flame that is generated by burning gas. A manipulation unit  62  for manipulating the plurality of cook-top burners  61  is disposed on a front end of the cook-top unit  60 . 
         [0037]    In another example, the cook-top unit  60  may include at least one electric heater. However, the at least one electric heater may not be exposed to the outside of the cook-top unit  60 . It should be noted that the current embodiment is not limited to a kind of heating source constituting the cook-top unit  60 . 
         [0038]    The oven unit  20  includes a cavity  21  that provides a cooking chamber  22  in which the food is cooked. The cavity  21  may have a rectangular parallelepiped shape having an opened front surface, but the present disclosure is not limited thereto. 
         [0039]    The oven unit  20  may include an upper burner  24  for cooking the food accommodated in the cooking chamber  22 . Also, the oven unit  20  may include a partition plate  190  for partitioning the cooking chamber  22  into a first chamber (see reference numeral  22   a  of  FIG. 13 ) and a second chamber (see reference numeral  22   b  of  FIG. 13 ). The partition plate  190  may be coupled to a rear wall  35  of the cavity  21  in the cooking chamber  22 . 
         [0040]    The oven unit  20  may further include a burner assembly (see reference numeral  23  of  FIG. 4 ) disposed in the second chamber (see reference numeral  22   b  of  FIG. 13 ). Also, the food may be accommodated in the first chamber (see reference numeral  22   a  of  FIG. 13 ). 
         [0041]    The burner assembly (see reference numeral  23  of  FIG. 4 ) and the upper burner  24  may operate at the same time. Alternatively, only one of the burner assembly (see reference numeral  23  of  FIG. 4 ) and the upper burner  24  may operate. 
         [0042]    The upper burner  24  may provide heat to the food from an upper side of the food within the cooking chamber  22 , and the burner assembly (see reference numeral  23  of  FIG. 4 ) may be disposed at a rear side of the food within the cooking chamber  22 . 
         [0043]    The oven unit  20  may further include a door  25  for opening/closing the cooking chamber  22 . The door  25  may be rotatably connected to the cooking appliance  1 . For example, the door  25  may open/close the cooking chamber  22  in a pull-down method in which a lower end of the door  25  rotates about an axis with respect to a lower end of the cooking chamber  22 . The current embodiment is not limited to the operation method of the door  25 . 
         [0044]    A door handle  26  that can be grasped by a user so as to rotate the door  25  may be disposed on an upper end of a front surface of the door  25 . 
         [0045]    The drawer unit  40  may keep the container, in which the food is contained, at a predetermined temperature. A drawer  41  in which the container is accommodated may be provided in the drawer unit  40 . The drawer  41  may be inserted into or withdrawn from the cooking appliance  1  in a sliding manner. A handle  42  to be grasped by the user may be disposed on a front surface of the drawer  41 . 
         [0046]    The control unit  50  may receive a manipulation signal for operating the cooking appliance  1 , particularly, a manipulation signal for operating at least one of the cook-top unit  60 , the oven unit  20 , and the drawer unit  40 . Also, the control unit  50  may display various information with respect to the operation of the cooking appliance  1  to the outside. 
         [0047]      FIG. 3  is a view of a state in which a burner assembly is removed in  FIG. 2 , and  FIG. 4  is an exploded perspective view of the burner assembly according to the first embodiment. 
         [0048]    Referring to  FIGS. 2 to 4 , the cavity  21  may include both sidewalls  31 , a bottom wall  32 , an upper wall  33 , and a rear wall  35 . 
         [0049]    In the current embodiment, the “front side” may represent a direction that is directed to a front surface of the cooking appliance  1 , and the “rear side” may represent a direction that is directed to a rear surface of the cooking appliance  1 . 
         [0050]    Also, the “front side” within the cooking chamber  22  may represent a direction that is directed towards the door  25  of the oven unit  20 , when closed, and the “rear side” may represent a direction that is directed towards the rear wall  35  of the cavity  21 . 
         [0051]    The partition plate  190  may be coupled to the rear wall  35  of the cavity  21 . That is, in the current embodiment, the partition plate  190  may be disposed on the rear wall  35  of the cavity  21 , and the burner assembly (see reference numeral  23 ) may be disposed in the second chamber (see reference numeral  22   b  of  FIG. 13 ) between the partition plate  190  and the rear wall  35  of the cavity  21 . Thus, since a recessed part  32   a  that is recessed downward from the bottom wall  32  of the cavity is defined, the cavity  21  may increase in volume by the amount of the recessed part  32   a . Generally, in a conventional cooking appliance, a conventional burner is disposed at the bottom wall  32  in the recessed part  32   a  occupying the volume of the recessed part  32   a . This also causes difficulty in cleaning the recess parts  32   a . Further, in the present embodiment, because the burner assembly is not disposed in the recessed part  32   a , there are no coupling holes found at the recessed part  32   a , which can potentially seep, food leftovers unto the floor, for example, if the coupling members are not properly coupled. 
         [0052]    The burner assembly  23  may include a burner device  100 , a fan  210 , and a fan motor  212 . 
         [0053]    The burner device  100  may include a burner  110  for burning gas to generate flame and a burner cover  130  covering the burner  110 . 
         [0054]    A burner hole  36  through which the burner  110  passes may be defined on the rear wall  35  of the cavity  21 . That is, the burner  110  may be disposed in the cooking chamber  22 , and a portion of the burner  110  may pass through the burner hole  36  and be disposed between the rear wall  35  of the cavity  21  and the outer case  11 . 
         [0055]    An exhaust hole  34  through which exhaust gas is discharged may be defined on the upper wall  33  of the cavity  21 . Alternatively, the exhaust hole  34  may not be defined on the upper wall  33 , but be defined on the rear wall  35  of the cavity  21 . 
         [0056]    The burner cover  130  may include a first cover  140  and a second cover  160 . For example, the first cover  140  covers the burner  110  at a front side of the burner  110 , and the second cover  140  covers the burner  110  at a rear side of the burner  110 . 
         [0057]    The burner device  100  may further include an igniter  189  for igniting a mixture gas supplied into the burner  110  and a stabilizer  180  for stabilizing flame. 
         [0058]    For example, the igniter  189  may be disposed on the burner  110 , and the stabilizer  180  may be disposed on the second cover  160 . A portion of the igniter  189  may pass through the second cover  160  and the upper wall  33  of the cavity  21 . In another example, the igniter  189  may be disposed on the first cover  140  or the second cover  160 . 
         [0059]    The burner device  100  will be described below with reference to the accompanying drawings. 
         [0060]    The fan  210  allows heated air to flow into the cooking chamber  22 . The fan motor  212  is disposed between the rear wall  35  of the cavity  21  and the outer case  11 , and the fan  210  is disposed in the second chamber (see reference numeral  22   b  of  FIG. 13 ) within the cooking chamber  22 . Thus, a shaft  213  of the fan motor  212  may pass through the rear wall  35  of the cavity  21  and be coupled to the fan  210 . The fan motor  212  may be fixed to the rear wall  35  of the cavity  21  or the outer case  11  by a motor mount (not shown). 
         [0061]    The partition plate  190  protects the burner device  100 . Also, the partition plate  190  may prevent food leftovers from contaminating the burner device  100  when the food is cooked. 
         [0062]    The partition plate  190  may include a front plate  191 , an extension part  193  extending from the front plate  191  toward the rear wall  35  of the cavity  21 , and a contact part  195  bent from the extension part  193 . 
         [0063]    An air suction hole  192  through which air within the cooking chamber  22  is suctioned is defined on the front plate  191 , and an air discharge hole  194  through which air heated by the burner device  100  is discharged into the cooking chamber  22  is defined on the extension part  193 . In another example, the air discharge hole  194  may be defined on the front plate  191  or defined on each of the front plate  191  and the extension part  193 . 
         [0064]    The contact part  195  may contact the rear wall  35  of the cavity  21  in a state where the contact part  195  covers the burner device  100 . A coupling hole  196  to which a coupling member (not shown) is coupled is defined on the contact part  195 . 
         [0065]    A lower end of the partition plate  190  may contact the bottom wall  32  of the cavity  21  in a state where the partition plate  190  is coupled to the rear wall  35  of the cavity  21  by the coupling member. That is, the front plate  191  and lower ends of the extension part  193  and the contact part  195  may contact the bottom wall  32  of the cavity  21 . Alternatively, the front plate  191  and the extension part  193  may contact the bottom wall  32  of the cavity  21 . 
         [0066]    Here, the partition plate  190  may contact the bottom wall  32  of the cavity  21  between the recessed part  32   a  of the bottom wall  32  and the rear wall  35  of the cavity  21 . 
         [0067]    The burner assembly  23  may further include a nozzle holder  220  for spraying gas into the burner  110 . 
         [0068]    The nozzle holder  220  may be disposed between the rear wall  35  of the cavity  21  and the outer case  11 . For example, the nozzle holder  220  may be fixed to the rear wall  35  of the cavity  21 . In another example, if an insulator is disposed on the outside of the cavity  21 , the nozzle holder  220  may be disposed on the insulator. 
         [0069]    The nozzle holder  220  may be aligned with the burner  110  passing through the rear wall  35  of the cavity  21  to spray gas into the burner  110 . 
         [0070]    The burner assembly  23  may further include a burner reflector  200 . The burner reflector  200  may have an opening  202  through which the fan  210  passes. The burner reflector  200  may be coupled to the rear wall  35  of the cavity  21  within the cooking chamber  22 . Here, the burner reflector  200  may be disposed between the burner cover  130  and the rear wall  35  of the cavity  21 . The burner reflector  200  may be configured to reflect heat of the burner  110  to the cooking chamber  22 . 
         [0071]      FIG. 5  is a perspective view of a burner device according to the first embodiment,  FIG. 6  is a perspective view illustrating a first cover of the burner device of  FIG. 5 , and  FIG. 7  is a cross-sectional view taken along line A-A′ of  FIG. 6 . 
         [0072]    Referring to  FIGS. 4 to 7 , the burner cover  130  includes a combustion chamber C in which gas is burned within the second chamber (see reference numeral  22   b  of  FIG. 13 ). Also, the burner  110  is disposed in the combustion chamber C. That is, the burner cover  130  partitions the second chamber (see reference numeral  22   b  of  FIG. 13 ) into the combustion chamber C and an exhaust passage (see reference symbol P 1  of  FIG. 13 ) in which the fan  210  is disposed. 
         [0073]    As shown in  FIG. 5 , the burner cover  130  includes a first cover  140  and a second cover  160 . 
         [0074]    Referring to  FIG. 6 , the first cover  140  may include a first plate  141 , a first extension part  148  extending backward from the first plate  141 , and a first coupling part  149  bent from the first extension part  148 . 
         [0075]    A first opening  142  through which air within the cooking chamber  22  passes, which is suctioned through the air suction hole  192  of the partition plate  190 , is defined on the first plate  141 . 
         [0076]    The air suction hole  192  of the partition plate  190  may have a grill shape (see  FIG. 4 ). That is, the air suction hole  192  may be defined as a plurality of holes. However, the air suction hole  192  that is defined as the plurality of holes may have a circular shape on the whole profile. 
         [0077]    Here, the first opening  142  may have a diameter equal to or greater than that of the profile of the air suction hole  192  so that the air passing through the air suction hole  192  smoothly passes through the first opening  142  of the first cover  140 . 
         [0078]    At least one first reinforcing part  144  for reinforcing strength of the first plate  141  may be disposed under the first opening  142  on the first plate  141 . The at least one first reinforcing part  144  may be disposed lengthwise in a horizontal direction. Although a plurality of first reinforcing parts  144  are vertically spaced apart from each other in  FIG. 6 , the current embodiment is not limited to the number and position of the first reinforcing part  144  shown. For example, the at least one first reinforcing part  141  may extend vertically lengthwise, and a plurality of first reinforcing parts  144  may be horizontally spaced apart from each other. 
         [0079]    The first reinforcing part  144  may protrude forward from the first plate  141 . That is, a portion of the first plate  141  may be formed so that the first reinforcing part  144  protrudes from the first plate  141  toward the door  25 . 
         [0080]    In the state where the partition plate  190  is disposed on the rear wall  35  of the cavity  21 , the first reinforcing part  144  may contact the partition plate  190 . Alternatively, in the state where the partition plate  190  is disposed on the rear wall  35  of the cavity  21 , the first reinforcing part  144  may be spaced apart from the partition plate  190 . In addition, when an external force is applied to the partition plate  190 , or the first plate  141  is expanded by heat, the first reinforcing part  144  may contact the partition plate  190 . 
         [0081]    According to the current embodiment, the thermal deformation of the first plate  141  may be minimized by the first reinforcing part  144 . Also, even though the first plate  141  is deformed, the first reinforcing part  144  may contact the partition plate  190  to prevent the first plate  141  from being additionally deformed. 
         [0082]    In another example, a portion of the plurality of first reinforcing part  144  may protrude forward from the first plate  141  toward the door  25 , and the another portion may protrude backward from the first plate  141 . Alternatively, at least one first reinforcing part  144  may protrude backward from the first plate  141  toward the rear wall  35  of the cavity  21 . 
         [0083]    A second reinforcing part  153  for reinforcing strength may be disposed on a circumferential part of the first opening  142  on the first plate  141 . For example, the first opening  142  may have a circular shape, and the second reinforcing part  153  may have a circular ring shape that surrounds the first opening  142 . However, the current embodiment is not limited to the shape and number of the first opening  142  and the shape and number of the second reinforcing part  153 . 
         [0084]    The second reinforcing part  153  may protrude forward from the first plate  141 . That is, a portion of the first plate  141  may be formed so that the second reinforcing part  153  protrudes from the first plate  141  toward the door  25 . 
         [0085]    In the state where the partition plate  190  is disposed on the rear wall  35  of the cavity  21 , the second reinforcing part  153  may contact the partition plate  190 . In another example, in the state where the partition plate  190  is disposed on the rear wall  35  of the cavity  21 , the second reinforcing part  153  may be spaced apart from the partition plate  190 . In addition, when an external force is applied to the partition plate  190 , or the first plate  141  is expanded by heat, the second reinforcing part  153  may contact the partition plate  190 . 
         [0086]    The first opening  142  of the first plate  141  may be disposed to face the air suction hole  192  of the partition plate  190 . Thus, since air passing through the air suction hole  192  of the partition plate  190  flows into the first opening  142  of the first plate  141  without being interfered in flow direction, the air may be smoothly circulated within the cooking chamber  22 . 
         [0087]    The first plate  141  may include a first insertion part  151  having at least one first inflow hole  143  through which air is introduced into the combustion chamber C. For example, the at least one first inflow hole  143  may be defined under the first reinforcing part  144  in the first plate  141 . 
         [0088]    Although a plurality of first inflow holes  143  are horizontally spaced apart from each other in  FIG. 6 , the current embodiment is not limited to the number, position, and shape of the first inflow hole  143 . 
         [0089]    The first insertion part  151  of the first cover  140  may pass through the bottom wall  32  of the cavity  21 . Thus, the at least one first inflow hole  143  may be defined outside the cavity  21 . 
         [0090]    Also, air outside the cavity  21  may be supplied into the combustion chamber C through the at least one first inflow hole  143 . 
         [0091]    An air guide  146  for guiding the air supplied into the combustion chamber C to the flame generated at the burner  110  and to increase a contact time between the air and the flame may be disposed on the first plate  141 . 
         [0092]    The air guide  146  may protrude backward from the first plate  141 . That is, a portion of the first plate  141  may be formed so that the air guide  146  protrudes from the first plate  141  toward the rear wall  35  of the cavity  21 . 
         [0093]    The air guide  146  may include linear parts  146   b  and  146   c  defined on one end or both ends of a curved part  146   a . Alternatively, the air guide  146  may include only the curved part  146   a.    
         [0094]    For example, the curved part  146   a  of the air guide  146  may have an arc shape. The curved part  146   a  may have a radius greater than that of the second reinforcing part  153 . 
         [0095]    Thus, a portion of the curved part  146   a  may be disposed between the second reinforcing part  153  and the first reinforcing part  144 . The curved part  146   a  may have curvature radius that is equal to or less than that of an inner periphery surface of the burner  110 . Thus, the air introduced into the combustion chamber C may be guided to the flame of the burner  110  by the air guide  146 . 
         [0096]    The air guide  146  may be integrated with the first plate  141  or coupled to the first plate  141 . 
         [0097]    Also, the air guide  146  may have a curved shape in at least a section to smoothly guide the air flow. 
         [0098]    At least one first coupling hole  150  that is coupled to the second cover  160  by a coupling member may be defined on the first coupling part  149 . 
         [0099]      FIG. 8  is a perspective view illustrating a second cover of the burner device of  FIG. 5 , and  FIG. 9  is a cross-sectional view taken along line B-B′ of  FIG. 8 . 
         [0100]    Referring to  FIGS. 4 ,  5 ,  8 , and  9 , the second cover  160  may include a second plate  161 , a second extension part  165  extending forward from the second plate  161 , and a second coupling part  166  bent from the second extension part  165 . 
         [0101]    A second opening  162  through which air heated in the combustion chamber C is discharged may be defined on the second plate  161 . The second opening  162  may have a circular shape, but is not limited thereto. The second opening  162  may have a diameter less than that of the first opening  142 . 
         [0102]    A burner coupling hole  170  to which the burner  110  is coupled may be defined on the second plate  161 . Also, at least one protrusion  164  for preventing the burner  110  from directly contacting the second plate  161  may be disposed on the second plate  161 . 
         [0103]    The at least one protrusion  164  may protrude toward the burner  110  in the state where the burner  110  is disposed on the second plate  161 . That is, a portion of the second plate  161  may be formed so that the at least one protrusion  164  protrudes toward the burner  110 . 
         [0104]    For example, the at least one protrusion  164  may contact the burner  110 . In another example, the at least one protrusion  164  may be adjacent to the burner  110  in a state where the protrusion  164  is spaced apart from the burner  110 . Also, when an external force is applied to the burner  110 , or the second plate  161  is expanded by heat, the at least one protrusion  164  may contact the burner  110 . Thus, in either event the at least one protrusion  164  may prevent the burner  110  from directly contacting the second plate  161 . 
         [0105]    Also, in case of the current embodiment, the at least one protrusion  164  may be disposed on the second plate  161  to minimize thermal deformation of the second plate  161 . 
         [0106]    In the state where the burner  110  is disposed on the second cover  160 , and the first cover  140  is coupled to the second cover  160 , the burner  110  may be spaced apart from the first plate  141  of the first cover  140  and the second plate  161  of the second cover  160 . Thus, air outside the cavity  21 , which is introduced into the combustion chamber C may flow between the first plate  141  and the burner  110 , and between the second plate  161  and the burner  110 . 
         [0107]    When the plurality of protrusions  164  are disposed on the second plate  161 , the plurality of protrusions  164  may be disposed to overlap the burner  110  in forward and backward directions when the burner  110  is disposed on the second cover  161 . 
         [0108]    At least one stabilizer coupling hole  163  to which the stabilizer  180  is coupled may be further defined on the second plate  161 . 
         [0109]    At least one second coupling hole  169  to which the coupling member passing through the first coupling hole  150  of the first coupling part  149  is coupled may be defined on the second coupling part  169 . 
         [0110]    In another example, the first and second coupling parts may not be disposed on the first and second covers, respectively. Also, the first extension part  148  of the first cover  140  and the second extension part  165  of the second cover  160  may be coupled to each other by a coupling member. 
         [0111]    The second cover  160  may further include a second insertion part  167  passing through the bottom wall  32  of the cavity  21 . At least one second inflow hole  167   a  may be defined on the second insertion part  167 . Thus, the at least one second inflow hole  167   a  may be disposed outside the cavity  21 . 
         [0112]    Also, air outside the cavity  21  may be supplied into the combustion chamber C through the at least one second inflow hole  167   a.    
         [0113]    In the state where the first cover  140  is coupled to the second cover  160 , the first insertion part  151  of the first cover  140  may be spaced apart from the second insertion part  167  of the second cover  160 . 
         [0114]    Although a plurality of second inflow holes  167   a  are horizontally spaced apart from each other in  FIG. 8 , the current embodiment is not limited to the number, position, and shape of the second inflow hole  167   a.    
         [0115]    According to the current embodiment, the air outside the cavity  21  may smoothly flow into the combustion chamber C by the at least one first inflow hole  143  defined on the first cover  140  and the at least one second inflow hole  167   a  defined on the second cover  160 . 
         [0116]    The second cover  160  may further include at least one installation part  168  for installing the second cover  160  on the rear wall  35  of the cavity  21 . 
         [0117]    The installation part  168  may be disposed on the second plate  161 , but is not limited thereto. Thus, the second plate  161  may be spaced apart from the rear wall  35  of the cavity  21  in the state where the second cover  160  is disposed on the rear wall  35  of the cavity  21  due to the installation of the installation part  168 . Also, the fan  210  may be disposed in a space between the second plate  161  and the rear wall  35  of the cavity  21 . That is, the fan  210  may be disposed in a separate space outside the combustion chamber C on which the burner cover  130  is disposed. 
         [0118]    The second cover  160  may further include a burner through-part  171  through which a portion of the burner  110  passes. The burner through-part  171  may protrude backward from the second plate  161  toward the rear wall  35  of the cavity  21 , but is not limited thereto. That is, the second plate  161  may be deformed so that the burner through-part  171  protrudes backward from the second plate  161 . 
         [0119]    Also, a burner through-hole  172  may be defined on the burner through-part  171 . The burner through-hole  172  may be aligned with the burner hole  36  defined on the rear wall  35  of the cavity  21 . 
         [0120]    In the state where the second cover  160  is disposed on the rear wall  35  of the cavity  21 , the burner through-part  171  may contact the rear wall  35  of the cavity  21 . 
         [0121]    The heated air passing through the second opening  162  of the burner cover  130  may flow into a space between the second cover  160  and the rear wall  35  of the cavity  21  and then be discharged into the cooking chamber  22  through the discharge hole  194  of the partition plate  190 . 
         [0122]    Here, in the state where the second cover  160  is disposed on the rear wall  35  of the cavity  21 , the burner through-part  171  may contact the rear wall  35  of the cavity  21  to prevent the heated air from being reintroduced into the combustion chamber C through the burner through-hole  172 . 
         [0123]    In addition, it may prevent the heated air from being discharged to the outside of the cavity  21  through the burner hole  36  of the rear wall  35  of the cavity  21 . 
         [0124]      FIGS. 10 and 11  are perspective views of the burner according to the first embodiment, and  FIG. 12  is a view of a state in which the burner of  FIG. 10  is linearly spread. 
         [0125]    Referring to  FIGS. 10 to 12 , the burner  110  according to the first embodiment includes a burner tube  111  having both ends spaced apart from each other. That is, in the current embodiment, the burner tube  111  may have a non-annular shape. 
         [0126]    The burner tube  111  may have a “U” shape, but is not limited thereto. A supply part  120  for receiving gas and air may be disposed on a first end  111   a  of the burner tube  111 , and a second end  111   b  of the burner tube  111  may be blocked. 
         [0127]    The supply part  120  may inclinedly extend from the first end  111   a  of the burner tube  111 . The gas and air supplied through the supply part  120  changes in flow direction from the first end  111   a  toward the second end  111   b  along the burner tube  111 . 
         [0128]    That is, in the current embodiment, the gas and air supplied through the supply part  120  may flow only in one direction within the burner tube  111 . 
         [0129]    The burner tube  111  may be formed in a curved shape on the whole, or at least one of the first and second ends  111   a  and  111   b  may be formed in a straight-line shape, and the other section may be formed in a curved shape. 
         [0130]    The burner tube  111  may include an inner periphery  112  and an outer periphery  113 . 
         [0131]    In the current embodiment, since the tube  111  has a “U” shape, the inner periphery  112  or the outer periphery  113  may have a plurality of curvatures different from each other. That is, the curvature of the inner or outer peripheries  112  and  113  of the burner tube  111  may vary in a longitudinal direction of the burner tube  111 . 
         [0132]    A plurality of gas outlet holes  114  and  115  are defined on the inner periphery  112  of the burner tube  111 . The plurality of gas outlet holes  114  and  115  are disposed in a plurality of rows. In the current embodiment, the “row” may represent a set of gas outlet holes that are arranged in a direction corresponding to the extension direction of the burner tube  111 . 
         [0133]    The gas outlet holes  114  and  115  arranged in the plurality of rows may include a plurality of first gas outlet holes  114  and a plurality of second gas outlet holes  115 . 
         [0134]    Although the gas outlet holes  114  and  115  arranged in two rows are defined on the inner periphery  112  of the burner tube  111  in  FIG. 10 , the current embodiment is not limited to the number of rows of the gas outlet holes. That is, the gas outlet holes arranged in a single row may be defined on the inner periphery  112  of the burner tube  111 . 
         [0135]    The gas outlet holes  114  and  115  arranged in one row may be spaced apart from each other in the longitudinal direction of the burner tube  111 . Also, the gas outlet holes  114  arranged in one row may be spaced apart from the gas outlet holes  115  arranged in the other row. 
         [0136]    Although not limited thereto, the gas outlet holes  114  and  115  adjacent to each other may be disposed in a zigzag form so that flames generated in the gas outlet holes  114  and  115  that are adjacent to each other and arranged in two rows do not interfere with each other. 
         [0137]    That is, the gas outlet holes  115  arranged in the other row may be disposed in a region corresponding to that between the gas outlet holes  114  adjacent to each other and arranged in one row. 
         [0138]    In the current embodiment, since the mixture gas in which the gas and air introduced through the supply part  120  are mixed with each other flows in only one direction (in arrow A direction) in the burner tube  111 , the gas outlet hole defined on one side of the first end  111   a  in the burner tube  111  has a diameter S 2  greater than S 1  of the gas discharge hole defined on one side of the second end  111   b.    
         [0139]    If a discharge amount of mixture gas in the gas outlet holes  114  and  115  increases, flame may be larger. Since the second end  111   b  is blocked within the burner tube  110 , the mixture gas may be concentrated into the second end  111   b . Thus, when the gas outlet hole defined on one side of the first end  111   a  has the same diameter as that defined on one side of the second end  111   b , an amount of mixture gas in one side of the second end  111   b  increases. Thus, the flame of the gas outlet hole defined on one side of the second end  111   b  may be significantly larger. 
         [0140]    However, according to the current embodiment, the gas outlet hole defined on one side of the second end  111   b  may have a diameter less than that of the gas outlet hole defined on the one side of the first end  111   a  so that the flames in the gas outlet holes  114  and  115  of the burner tube  111  are generally uniform whether on one side of the second end  111   b  or on one side of the first end  111   a.    
         [0141]    Alternatively, the gas discharge hole in the burner tube  111  including the second end  111   b  with respect to a bisected length of the burner tube  111  may have a diameter less than that of the gas discharge hole in the burner tube  111  including the first end  111   a.    
         [0142]    The inner periphery  112  of the burner tube  111  may have a minimum curvature radius greater than a maximum curvature radius of the curved part  146   a  of the air guide  146  of the first cover  140 . 
         [0143]    Also, the inner periphery  112  of the burner tube  111  may have a minimum curvature radius greater than a radius of the second opening  162  of the second cover  160 . When the second opening  162  has a non-annular shape, the inner periphery  112  of the burner tube  111  may have a minimum curvature radius greater than a maximum length of the second opening  162 . 
         [0144]    A plurality of brackets  125  and  126  for installing the burner tube  111  on the second cover  160  may be disposed on the burner tube  111 . One bracket  126  of the plurality of brackets  125  and  126  may be disposed on the second end  111   b  of the burner tube  111 . 
         [0145]    Although the plurality of brackets  125  and  126  are coupled to the second cover  160  by using a screw, the current embodiment is not limited to the coupling method between the plurality of brackets  125  and  126  and the second cover  160 . 
         [0146]    In the state where the plurality of brackets  125  and  126  are coupled to the second cover  160 , the burner tube  111  may be spaced apart from the second plate  161  of the second cover  160 . 
         [0147]    The burner tube  111  may further include an igniter support  127  for installing the igniter  189 . For example, the igniter support  127  may be disposed at a position adjacent to the supply part  120  in the burner tube  110 . The igniter support  127  may have a coupling hole  128  to which the coupling member for coupling with the igniter  127  is coupled. 
         [0148]    The supply part  120  may include a plurality of first guides  121  and  122  for aligning the supply part  120  with the nozzle holder  220 . The plurality of first guides  121  and  122  may be spaced apart from each other, and air outside the cavity  21  may be introduced into the supply part  120  together with the gas sprayed from the nozzle holder  220  through the opening between the plurality of first guides  121  and  122 . 
         [0149]    The supply part  120  may pass through the burner through-hole  172  of the second cover  160  and the burner hole  36  of the rear wall  35  of the cavity  21 . 
         [0150]    According to the current embodiment, the plurality of gas outlet holes may be defined on the inner periphery of the burner, and air may pass through the region in which the plurality of gas outlet holes are defined. Thus, air within the cooking chamber may be sufficiently heated by the flame of the burner. 
         [0151]    Also, as the flames are generated in the inner periphery of the burner, a distance between the flames may be gradually reduced toward the gas outlet holes to prevent the flames from being extinguished by the air flow. 
         [0152]      FIG. 13  is a vertical cross-sectional view of a state in which the burner assembly is installed in the cavity according to the first embodiment. 
         [0153]    Referring to  FIG. 13 , a through-hole  32   c  through which the insertion parts  151  and  167  of the burner cover  130  pass may be defined on the bottom wall  32  of the cavity  21 . Thus, since the insertion parts  151  and  167  of the burner cover  130  pass through the through hole  32   c , the insertion parts  151  and  167  may be disposed outside the cavity  21 . 
         [0154]    The first insertion part  151  of the first cover  140  and the second insertion part  167  of the second cover  160  may be spaced apart from each other to form a third inflow hole  167   b.    
         [0155]    Also, the fan  210  is disposed in the exhaust passage P 1  that is an external to the combustion chamber C. The exhaust passage P 1  (or that may be called “exhaust chamber”) may be defined by an outer surface of the burner cover  130 , the rear wall  35  (or the burner reflector) of the cavity  21 , and the partition plate  190 . 
         [0156]    Thus, according to the current embodiment, the plurality of gas outlet holes  114  and  115  may be defined on the inner periphery of the burner  110 , and the fan  210  may be disposed in the combustion chamber C and the independent exhaust passage P 1  to prevent the fan  210  from being heated by the flame of the burner  110 . Also, after the flame of the burner  110  contacts the air to heat the air, the air may flow into the fan  210 . Thus, the air may be sufficiently heated by the heat of the flame. 
         [0157]    Also, since the air is heated by the flame generated in the inner periphery of the burner in the combustion chamber C to flow into the fan, even though the flame is curved toward the fan by the air flow due to the rotation of the fan, the air may be heated by the flame. 
         [0158]    Hereinafter, an operation of the burner assembly will be described. 
         [0159]    When an operation of the burner assembly  100  starts, gas is sprayed from the nozzle holder  220  into the supply part  120  of the burner  110 . Then, air A 1  (air outside the cavity) around the supply part  120  together with the gas may be supplied into the supply part  120 . Here, the air A 1  around the supply part  120  may be naturally supplied into the supply part  120  by a pressure difference because a low pressure is formed around the gas supplied into the supply part  120  (natural air-supply method). Thus, when the air is supplied into the supply part  120  by using the natural air-supply method, air that is required for burning gas may not be sufficiently supplied into the supply part  120 . In this case, the mixture gas in which the gas and air are mixed may be incompletely burned, and thus an amount of generated carbon dioxide may increase by the incomplete combustion. 
         [0160]    However, according to the current embodiment, the insertion parts  151  and  167  of the burner cover  130  may pass through the bottom wall  32  of the cavity  21  and be disposed outside the cavity  21 . Also, since the plurality of inflow holes  143 ,  167   a , and  167   b  are defined outside the cavity  21 , additional air for burning the mixture gas of the burner  110  may be introduced into the combustion chamber C. 
         [0161]    The additional air A 2  introduced into the combustion chamber C may flow into the burner  110 . As described above, since the burner  110  is spaced apart from the first plate  141  of the first cover  140  and the second plate  161  of the second cover  160 , the air within the combustion chamber C may flow into the space between the burner  110  and the first plate  141  and the space between the burner  110  and the second plate  161 . 
         [0162]    Thus, the air within the combustion chamber C may smoothly flow to the first and second gas outlet holes  114  and  115 , which are defined on the burner  110 . 
         [0163]    Also, since the air guide  146  is disposed on the first cover  140 , the additional air A 2  may be guided to the first gas outlet hole  114  by the air guide  146 . Thus, the additional gas A 2  may be sufficiently supplied to the first gas outlet hole  114 . 
         [0164]    In the state where the mixture gas is supplied into the burner  110 , the mixture gas may be ignited by the igniter  189  to generate flame in the burner  110 . Also, the fan motor  212  may be turned on to rotate the fan  210 . 
         [0165]    When the fan  210  rotates, the air within the first chamber  22   a  may be introduced into the combustion chamber C within the second chamber  22   b  through the air suction hole  192  of the partition plate  190 . Here, the air introduced into the combustion chamber C may pass through the region in which the inner periphery of the burner is defined. 
         [0166]    The air introduced into the combustion chamber C may be heated by the flame generated in the burner  110 , and then be discharged from the combustion chamber C through the opening  184  of the stabilizer  180 . 
         [0167]    The air discharged from the combustion chamber C may flow into the exhaust passage P 1  defined between the second cover  160  and the rear wall  35  of the cavity  21  and then be disposed into the first chamber  22   a  through the discharge hole  194  of the partition plate  190 . Referring to  FIG. 4 , the heated air discharged through the discharge holes  194  located at the extension part  193  and/or the front plate  191  provides for a better dispersement of heated air in the cooking chamber  22 . In the conventional cooking appliance, the conventional burner is located at the bottom of the cooking chamber  22  and at the recessed part  32   a . Thus, the heated air is hotter at the bottom than at the top. In contrast, the burner assembly of the present embodiment located at the rear wall  35  of the cavity  21  and discharging heated air through discharge holes  194  provides for a better dispersement of heated air in the cooking chamber  22  to cook foods. 
         [0168]    According to the current embodiment, the burner cover  130  may define the independent combustion chamber C, and the combustion chamber C and the exhaust passage P 1  may be partitioned by the burner cover  130 . 
         [0169]    Thus, it may prevent the air flowing into the exhaust passage P 1  from being reintroduced into the combustion chamber C. 
         [0170]    Although the burner assembly is disposed on the rear wall of the cavity within the cavity in the foregoing embodiment, the present disclosure is not limited thereto. For example, the burner assembly may be disposed on the rear wall of the cavity that is outside of the cavity. 
         [0171]    Alternatively, the burner assembly may be disposed on one sidewall among the sidewalls of the cavity. 
         [0172]    Hereinafter, a method of assembling the burner assembly will be described. 
         [0173]    First, the burner reflector  200  may be coupled to the rear wall  35  of the cavity  21  inside the cooking chamber  22 . 
         [0174]    Also, the nozzle holder  220  may be coupled to the rear wall  35  outside the cavity  20  regardless of whether the burner reflector  200  is coupled. 
         [0175]    Then, in the state where the fan  210  is disposed at a front side of the rear wall  35  of the cavity  21 , the fan  210  may be coupled to the fan motor  212 . 
         [0176]    Also, in the state where the stabilizer  180  is disposed on the second cover  160 , the second cover  160  may be coupled to the rear wall  35  of the cavity inside the cooking chamber  22 . Then, the burner  110  is disposed on the second cover  160 . Also, the first cover  140  is coupled to the second cover  160 . 
         [0177]    Finally, the partition plate  190  is coupled to the rear wall  35  of the cavity  21  within the cooking chamber  22 . 
         [0178]    Although the burner cover  130  is constituted by two parts to define the combustion chamber C in the foregoing embodiment, the present disclosure is not limited thereto. For example, one cover or at least three covers may define the combustion chamber C. That is, if the combustion chamber C and the exhaust passage P 1  are partitioned, the present disclosure is not limited to the shape of the burner cover  130  and the number of covers constituting the burner cover. 
         [0179]    Also, although the fan is disposed at a rear side of the burner cover  130 , and the air heated by the burner flows into the fan in the foregoing embodiment, the present disclosure is not limited thereto. For example, the fan may be disposed at a front side of the burner cover, and the burner may heat the air passing through the fan. However, in case of the former, the fan may be a fan by which air flowing in an axis direction is directed into air flowing in a radius direction to radially discharge the air. In case of the latter, the fan may be a fan for axially discharging air flowing in an axis direction. 
         [0180]      FIG. 14  is a perspective view of a cooking appliance according to a second embodiment, and  FIG. 15  is a front view of a state in which a second door is removed in  FIG. 14 . 
         [0181]    The current embodiment is the same as the first embodiment except for the number of oven unit. Thus, a characterizing part according to the current embodiment will be principally described. 
         [0182]    Referring to  FIGS. 14 and 15 , a cooking appliance  2  according to a second embodiment may include a plurality of oven units  300  and  400 . 
         [0183]    The plurality of oven units  300  and  400  may include a first oven unit  300  and a second oven unit  400  disposed under the first oven unit  300 . The plurality of oven units  300  and  400  may include doors  310  and  410 , respectively. 
         [0184]    A burner assembly  430  may be disposed on at least one of the plurality of oven units  300  and  400 . Since the burner assembly  430  has the same structure as that of the first embodiment, its detailed description will be omitted. 
         [0185]    Although the burner assembly  430  is disposed on the second oven unit  400  in  FIG. 15 , the burner assembly  430  may be disposed on the first oven unit  300  or each of the plurality of oven units  300  and  400 . 
         [0186]      FIG. 16  is a perspective view of a burner according to a third embodiment. 
         [0187]    The current embodiment is the same as the first embodiment except for a shape of a burner. Thus, a characterizing part according to the current embodiment will be principally described. 
         [0188]    Referring to  FIG. 16 , a burner  510  according to a third embodiment may have a “∩” shape. That is, the burner  510  according to the current embodiment may have a shape that is convexly rounded upward. 
         [0189]      FIG. 17  is a perspective view of a burner according to a fourth embodiment. 
         [0190]    The current embodiment is the same as the first embodiment except for a shape of a burner. Thus, a characterizing part according to the current embodiment will be principally described. 
         [0191]    Referring to  FIG. 17 , a burner  520  according to a fourth embodiment may have a “⊂” shape. That is, the burner  520  according to the current embodiment may have a shape that is convexly rounded in a left direction. 
         [0192]      FIG. 18  is a perspective view of a burner according to a fifth embodiment. 
         [0193]    The current embodiment is the same as the first embodiment except for a shape of a burner. Thus, a characterizing part according to the current embodiment will be principally described. 
         [0194]    Referring to  FIG. 18 , a burner  530  according to a fifth embodiment may have a “⊃” shape. That is, the burner  530  according to the current embodiment may have a shape that is convexly rounded in a right direction. 
         [0195]    Although the burner has the “U” shape on the whole, but is disposed in different directions in the first, third, and fifth embodiments, the present disclosure is not limited thereto. For example, the burner may have various shapes such as a “C” shape and also be disposed in various directions. 
         [0196]      FIG. 19  is a perspective view of a burner according to a sixth embodiment. 
         [0197]    The current embodiment is the same as the first embodiment except for a shape of a burner. Thus, a characterizing part according to the current embodiment will be principally described. 
         [0198]    Referring to  FIG. 19 , a burner  610  according to a sixth embodiment may have a “U” shape on the whole. However, a section of the burner  610  in a direction perpendicular to a flow direction of a gas may have a non-annular shape. For example, a section of the burner  610  in the direction perpendicular to the flow direction of the gas may have a square shape. 
         [0199]    The burner  610  may include a burner tube  611 . A supply part may be disposed on a first end of the burner tube  611 , and a second end may be blocked. 
         [0200]    The burner tube  611  includes an inner periphery  612  and an outer periphery  613 . Also, a plurality of gas outlet holes  614  and  615  may be defined on the inner periphery  612 . 
         [0201]    The same effect as that described in the first embodiment may be obtained by the burners according to the third to sixth embodiments. 
         [0202]      FIG. 20  is a perspective view of a burner according to a seventh embodiment. 
         [0203]    The current embodiment is the same as the first embodiment except for a shape of a burner. Thus, a characterizing part according to the current embodiment will be principally described. 
         [0204]    Referring to  FIG. 20 , a burner  710  according to a seventh embodiment may include a burner tube  711 . The burner tube  711  may include a first end  711   a  in which a supply part is provided and a second end  711   b  that is blocked. Thus, a gas within the burner tube  711  may flow in only one direction. 
         [0205]    A plurality of gas outlet holes  712  may be defined on an inner periphery of the burner tube  711 . 
         [0206]    The portion of the burner tube  711  in which the plurality of gas outlet holes  712  are defined may have a constant curvature. 
         [0207]      FIG. 21  is a perspective view of a burner according to an eighth embodiment. 
         [0208]    The current embodiment is the same as the first embodiment except for a shape of a burner. Thus, a characterizing part according to the current embodiment will be principally described. 
         [0209]    Referring to  FIG. 21 , a burner  810  according to an eighth embodiment may include a burner tube  811  having a circular ring shape. The burner tube  811  includes an inner periphery  812  and an outer periphery  813 . Also, a plurality of gas outlet holes  814  and  815  may be defined on the inner periphery  812 . 
         [0210]    Since the tube  811  has the circular ring shape, the inner periphery  812  or the outer periphery  813  may have a constant curvature. 
         [0211]    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.