Patent Publication Number: US-2021190312-A1

Title: Cooking device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority under 35 U.S.C. § 119 and 35 U.S.C. § 365 to Korean Patent Application No. 10-2015-0007751, filed in Korea on Jan. 16, 2015, which is hereby incorporated by reference. 
     BACKGROUND 
     1. Field 
     The present disclosure relates to a cooking device. 
     2. Background 
     A cooking device is a device for cooking food using heat from a heat source. For example, a cooking device generally includes an oven range having an oven chamber in which the food is cooked, and a burner provided in the oven chamber to burn gas. 
     An example of a conventional oven range is provided in Korean Patent Publication No. 2010-0013997 (published on Feb. 10, 2010). Korean Patent Publication No. 2010-0013997 describes an oven range having a burner chamber provided below a bottom surface thereof, which forms an oven chamber, and a lower burner installed at the burner chamber to convectively heat food in the oven chamber. However, such arrangement is perceived to have some disadvantages. 
     For example, to provide air heated by the lower burner from the burner chamber to the oven chamber, the oven chamber and the burner chamber must be in communication with each other. However, because the burner chamber is provided below the oven chamber, a part of the bottom surface of the oven chamber should be opened. However, when a part of the bottom surface of the oven chamber is opened, food leftovers or the like may be introduced into the burner chamber through an opened portion of the oven chamber and the burner chamber, while the food is cooked in the oven chamber or the food is put into or taken out of the oven chamber. 
     Also, because a part of the bottom surface of the oven chamber is opened, it is not easy to clean the oven chamber due to an opening of the bottom surface. 
     Also, because the lower burner is installed below the oven chamber, a cavity capacity of the oven chamber is reduced. 
     Moreover, in arrangements having the lower burner installed outside of the oven chamber, when it is necessary to replace or check an ignition unit for igniting a mixed gas supplied to the lower burner, the oven chamber includes an outer case that needs to be separated, which is complicated and time consuming. 
     SUMMARY 
     The present disclosure is directed to an improved cooking device having a cooking chamber that is easier to clean and has an increased capacity compared to a conventional cooking device. 
     Moreover, the present disclosure is directed to an improved cooking device having an ignition unit for igniting a mixed gas that is easier to access compared to the ignition unit of a conventional cooking device. 
     According to an embodiment of the invention, there is provided a cooking device including a frame that forms a cooking chamber; a burner provided in the frame and having a plurality of gas outlet holes; an ignition unit provided in the frame to ignite a mixed gas discharged from at least one of the plurality of gas outlet holes; and a fixing device to affix a position of the ignition unit with respect to the burner. 
     According to another embodiment of the invention, there is provided a cooking device including a frame that forms a cooking chamber; a burner cover provided in the frame to form a combustion chamber that is partitioned from the cooking chamber; a burner provided at the combustion chamber and having a plurality of gas outlet holes; an ignition unit provided at the combustion chamber to ignite a mixed gas discharged from at least one of the plurality of gas outlet holes; and a fixing device to support the ignition unit. 
     It is to be understood that both the foregoing general description and the following detailed description of the invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings: 
         FIG. 1  is a perspective view of a cooking device according to an embodiment of the present disclosure; 
         FIG. 2  is a front view illustrating a state in which a door is removed from the cooking device according to an embodiment of the present disclosure; 
         FIG. 3  is a view illustrating a state in which a burner assembly removed from the cooking device illustrated in  FIG. 2 ; 
         FIG. 4  is an exploded perspective view of the burner assembly according to one embodiment of the present disclosure; 
         FIG. 5  is a perspective view of a burner device according to an embodiment of the present disclosure; 
         FIG. 6  is a perspective view of a first cover of the burner device of  FIG. 5 ; 
         FIG. 7  is a cross-sectional view taken along line A-A of  FIG. 6 ; 
         FIG. 8  is a perspective view of a second cover of the burner device of  FIG. 5 ; 
         FIG. 9  is a cross-sectional view taken along line B-B of  FIG. 8 ; 
         FIG. 10  is a view illustrating a state in which an ignition unit installed at a burner according to an embodiment of the present disclosure; 
         FIG. 11  is a view illustrating a state in which the ignition unit is separated from the burner according to an embodiment of the present disclosure; 
         FIG. 12  is a perspective view of a second bracket which is coupled to the ignition unit; 
         FIG. 13  is a view illustrating a state in which the burner having the ignition unit is installed at the burner cover; 
         FIG. 14  is a vertical cross-sectional view illustrating a state in which the burner assembly is installed at a frame according to an embodiment of the invention; 
         FIG. 15  is a perspective view of a cooking device according to another embodiment of the present disclosure; and 
         FIG. 16  is a front view of the cooking device of  FIG. 15  in which a second door is separated. 
     
    
    
     DETAILED DESCRIPTION 
     Advantages, features, and methods for achieving those of embodiments may become apparent upon referring to embodiments described later in detail together with the attached drawings. However, embodiments are not limited to the embodiments disclosed hereinafter, but may be embodied in different modes. The same reference numbers may refer to the same elements throughout the specification. 
       FIG. 1  is a perspective view of a cooking device according to an embodiment of the present disclosure, and  FIG. 2  is a front view illustrating a state in which a door is removed from the cooking device according to an embodiment of the present disclosure. 
     Referring to  FIGS. 1 and 2 , a cooking device  1  may include an oven unit  20 . Cooking device  1  may further include a cook-top unit  60 . Cooking device  1  may further include a drawer unit  40 . Cooking device  1  may further include a control unit  50 . Cooking device  1  may further include an outer case  11 , which may cover some of or all of both side surfaces and rear surfaces of the oven unit  20  and the drawer unit  40 . 
     It is understood that cook-top unit  60  and drawer unit  40  may be omitted depending on a type of cooking device  1 . 
     Cook-top unit  60 , oven unit  20 , and drawer unit  40  may be provided at an upper portion, a center portion and a lower portion of the cooking device  1 , respectively. Control unit  50  may be provided at a rear portion of an upper surface of cooking device  1 . 
     Cook-top unit  60  may include a plurality of cook-top burners  61 . Cook-top burners  61  may heat a container in which food is put or may directly heat the food using a flame generated by burning a gas, and thus may cook or heat the food. An operational unit  62  to operate the plurality of cook-top burners  61  may be provided at a front end of cook-top unit  60 . Alternatively, operational unit  62  may be provided at an upper surface of cook-top unit  60 . 
     It is understood that the invention is not limited to any particular type of heating source to form cook-top unit. For example, cook-top unit  60  may include one or more electric heaters. However, the one or more electric heaters may not project outside of the cook-top unit  60 . 
     Oven unit  20  may include a frame  21  that forms a cooking chamber  22  in which the cooking of the food is performed. 
     For example, frame  21  may be formed in a rectangular parallelepiped shape of which a front surface is opened, but is not limited such particular shape. 
     Oven unit  20  may include a burner assembly  23  for cooking the food accommodated in cooking chamber  22 . Oven unit  20  may further include an upper burner  24 . 
     The burner assembly  23  and the upper burner  24  may be simultaneously operated, or may be operated one at a time. 
     Upper burner  24  provides heat to the food from above the food in frame  21 , and burner assembly  23  may be provided at a rear of the food in frame  21 . For example, upper burner  24  may be installed at an upper wall of frame  21 , and burner assembly  23  may be installed at a rear wall of frame  21 . 
     Oven unit  20  may further include a door  25  to open and close (e.g., access) cooking chamber  22 . Door  25  may be rotatably connected or hinged to cooking device  1 . For example, door  25  may open and close the cooking chamber  22  in a pull-down method whereby an upper end of door  25  is rotated up and down about a lower end of door  25 . It is thus understood that the disclosed embodiments are not limited to a particular operating method to open and close door  25 . 
     A door handle  26  which is gripped or manipulated by a user&#39;s hand to rotate door  25  may be provided at an upper end of a front surface of door  25 . 
     Drawer unit  40  may also function to maintain the container, in which the food is put, at a predetermined temperature. A drawer  41  in which the container is accommodated may be provided at drawer unit  40 . Drawer  41  may be inserted into or withdrawn from cooking device  1  in a sliding method. A handle  42  which is gripped or manipulated by the user may also be provided at a front surface of drawer  41 . 
     Control unit  50  may receive an operation signal to operate cooking device  1 , specifically, an operation signal to operate at least one of cook-top unit  60 , oven unit  20 , and drawer unit  40 . Also, control unit  50  may display a variety of information about the operation of the cooking device  1 . 
       FIG. 3  is a view illustrating a state in which the burner assembly is removed from  FIG. 2 , and  FIG. 4  is an exploded perspective view of the burner assembly according to an embodiment of the present disclosure. 
     Referring to  FIGS. 2, 3, and 4 , frame  21  may include both side walls  31 , a bottom wall  32 , an upper wall  33  and a rear wall  35 . However, the frame is not limited to such structure. 
     In the disclosed embodiments, regarding cooking device  1 , a “front” is generally understood to be a direction toward a front surface of cooking device  1 , and a “rear” is generally understood to be a direction toward a rear surface of cooking device  1 . Regarding cooking chamber  22 , a “front” is generally understood to be a direction toward door  25  of oven unit  20 , and a “rear” is generally understood to be a direction toward rear wall  35  of frame  21 . 
     Burner assembly  23  may be coupled to rear wall  35  of frame  21 . Thus, because burner assembly  23  is not located below frame  21 , but is installed at rear wall  35  of frame  21 , a recessed portion  32   a  which is recessed downward may be formed at bottom wall  32  of frame  21 . Such configuration increases a capacity of frame  21 . 
     The above-described embodiment provides an example of burner assembly  23  installed at rear wall  35  of frame  21 . However, it is understood that burner assembly  23  may alternatively be installed at one of both side walls  31  of frame  21 . 
     Burner assembly  23  may include a burner device  100 . Burner device  100  may include a burner  110  to generate a flame by burning a gas, and a burner cover  130  to cover burner  110 . Burner assembly  23  may further include an assembly cover  190  to cover burner device  100 . Burner assembly  23  may include a fan  210  and a fan motor  212 . It is understood that the phrase “located in the frame”—or the like—means “located in a space formed by the frame”—or the like. 
     A burner hole  36  through which burner  110  passes may be formed at rear wall  35  of frame  21 . That is, burner  110  may be located in frame  21 , and a part thereof may pass through burner hole  36 , and may be located between rear wall  35  of frame  21  and outer case  11 . 
     An exhaust hole  34  through which an exhaust gas is discharged may be formed at upper wall  33  of frame  21 . Alternatively, exhaust hole  34  may be formed at rear wall  35  or one of both side walls  31  of frame  21 . 
     Burner cover  130  may include a first cover  140  and a second cover  160 . For example, at least a part of first cover  140  may cover burner  110  at a front side of burner  110 , and at least a part of second cover  160  may cover burner  110  at a rear side of burner  110 . 
     Burner device  100  may further include an ignition unit  230  to ignite the mixed gas supplied to burner  110 . Burner device  100  may further include a stabilizer  180  to stabilize the flame generated from burner  110 . Ignition unit  230  may be installed or provided in frame  21 , e.g., at burner  110 . A portion of ignition unit  230  may be located in burner cover  130  when ignition unit  230  is installed at burner  110 . 
     Burner device  100  will be described below with reference to the accompanying drawings. 
     Fan motor  212  may be disposed or provided between rear wall  35  of frame  21  and outer case  11 . Fan  210  may be located inside frame  21 . Therefore, a shaft  213  of fan motor  212  may pass through rear wall  35  of frame  21  and may be coupled to fan  210 . Fan motor  212  may be attached to rear wall  35  of frame  21  or outer case  11  by a motor mount, which is not illustrated. 
     Assembly cover  190  may protect burner device  100 . Moreover, assembly cover  190  may prevent food from accumulating in burner device  100  during a cooking operation. Assembly cover  190  may include a front plate  191 , an extension part  193  which extends from front plate  191  toward rear wall  35  of frame  21 , and a contact part  195  which is bent from extension part  193 . 
     An air suction port  192  through which the air in the cooking chamber  22  is suctioned may be formed at front plate  191 , and an air discharge port  194  through which the air heated by burner device  100  is discharged to the cooking chamber  22  may be formed or provided at the extension part  193 . Alternatively, air discharge port  194  may be formed or provided at front plate  191 , or may be formed or provided at each of front plate  191  and extension part  193 . 
     Contact part  195  may be in contact with rear wall  35  of frame  21 , while covering burner device  100 . A fastening hole  196  to which a fastening member is attached, which is not shown, may be provided at contact part  195 . 
     When assembly cover  190  is fastened to rear wall  35  of frame  21  by fastening member, a lower end of assembly cover  190  may be in contact with bottom wall  32  of frame  21 . That is, lower ends of front plate  191 , extension part  19 , and contact part  195  may be in contact with bottom wall  32  of frame  21 . Alternatively, front plate  191  and extension part  193  may be in contact with bottom wall  32  of frame  21 . 
     At this time, assembly cover  190  may be in contact with bottom wall  32  of frame  21  between recessed portion  32   a  of bottom wall  32  and rear wall  35  of frame  21 . Burner assembly  23  may further include a nozzle holder  220  to inject the gas to burner  110 . Nozzle holder  220  may be located between rear wall  35  of frame  21  and outer case  11 , and may be attached to, for example, rear wall  35  of frame  21 . As another example, when an insulating material is installed at an outside of frame  21 , nozzle holder  220  may be installed at the insulating material. Nozzle holder  220  may be aligned with burner  110  passed through rear wall  35  of frame  21  and may inject the gas to burner  110 . 
       FIG. 5  is a perspective view of the burner device according to an embodiment of the present disclosure,  FIG. 6  is a perspective view of 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 . 
     Referring to  FIGS. 5, 6, and 7 , burner cover  130  may form a combustion chamber C in which the gas is burned. The burner  110  may be located at combustion chamber C. 
     As described above, burner cover  130  may include first cover  140  and second cover  160 . The first cover  140  may include a first plate  141 . The first cover  140  may further include a first extension part  148  which extends from first plate  141  toward a rear side thereof, and a first fastening part  149  which is bent from first extension part  148 . The first plate  141  may include a first opening  142  through which the air in cooking chamber  22  suctioned through air suction port  192  of assembly cover  190  passes. 
     The air suction port  192  of assembly cover  190  may be formed having a grille-like shape. The air suction port  192  may be formed by a plurality of holes. The entire shape of the air suction port  192  formed by the plurality of holes may be a circle shape. 
     To allow the air passed through air suction port  192  to smoothly pass through the first opening  142  of the first cover  140 , a diameter of first opening  142  may be the same as or larger than a diameter of the shape of air suction port  192 . 
     The first plate  141  may further include one or more first reinforcing parts  144  located below the first opening  142  to strengthen the first plate  141 . The one or more first reinforcing parts  144  may be transversely formed. 
       FIG. 6  illustrates an example in which a plurality of first reinforcing parts  144  are arranged to be vertically spaced apart from each other. It is understood that the present disclosure is not limited to a particular number and an arrangement of the first reinforcing parts  144 . For example, the one or more first reinforcing parts  144  may extend vertically. Alternatively, the one or more first reinforcing parts  144  may be arranged to be horizontally spaced apart from each other. 
     The first reinforcing parts  144  may protrude from first plate  141  toward a front side thereof. That is, a portion of first plate  141  may be formed so that the first reinforcing parts  144  protrude from first plate  141  toward door  25 . 
     When burner assembly  23  is installed at rear wall  35  of frame  21 , first reinforcing parts  144  may be in contact with assembly cover  190 . Alternatively, when burner assembly  23  is installed at rear wall  35  of frame  21 , the first reinforcing parts  144  may be spaced apart from assembly cover  190 , and may be in contact with assembly cover  190  when an external force is applied to assembly cover  190 , or first plate  141  or assembly cover  190  expands due to heat. 
     Accordingly, thermal deformation of first plate  141  may be minimized by first reinforcing parts  144 , and also, even when first plate  141  is deformed, additional deformation of first plate  141  may be prevented because first reinforcing parts  144  are in contact with assembly cover  190 . 
     As another example, a part of the plurality of first reinforcing parts  144  may protrude toward a front of first plate  141 , and other part thereof may protrude toward a rear of first plate  141 . Alternatively, one or more first reinforcing parts  144  may protrude toward the rear of first plate  141 . 
     The first plate  141  may further include a second reinforcing part  153  which is located around a portion of or the entirety of the first opening  142  to reinforce the strength. For example, first opening  142  may be formed in a circular shape, and second reinforcing part  153  may be formed in a ring-like shape which surrounds first opening  142 . However, it is understood that the present disclosure is not limited to a particular shape and number of first opening  142 , or a particular shape and number of second reinforcing part  153 . The second reinforcing part  153  may protrude toward a front of first plate  141 . That is, a portion of the first plate  141  may be formed so that second reinforcing part  153  protrudes from first plate  141  toward door  25 . 
     When burner assembly  23  is installed at rear wall  35  of frame  21 , second reinforcing part  153  may be in contact with assembly cover  190 . As another example, when burner assembly  23  is installed at rear wall  35  of frame  21 , the second reinforcing part  153  may be spaced apart from assembly cover  190 , and may be in contact with assembly cover  190  when an external force is applied to the assembly cover  190  or first plate  141  or assembly cover  190  expands due to heat. 
     The first opening  142  of first plate  141  may be disposed to face air suction port  192  of assembly cover  190 . Therefore, since the air passed through air suction port  192  of assembly cover  190  flows to first opening  142  of first plate  141  without a change in a flow direction, air circulation may be smoothly performed inside frame  21 . 
     The first plate  141  may further include a first insertion part  151  having one or more first introduction holes  143  through which the air is provided into combustion chamber C. For example, the one or more first introduction holes  143  may be located below first reinforcing parts  144  at first plate  141 . 
       FIG. 6  illustrates an example in which a plurality of first introduction holes  143  are arranged to be horizontally spaced apart from each other. Again, it is understood that the invention is not limited to a particular number, arrangement, and/or shape of the first introduction holes  143 . 
     The first insertion part  151  may pass through the bottom wall  32  of the frame  21 . The one or more first introduction holes  143  may be located outside of frame  21 . The air outside the frame  21  may be provided to the combustion chamber C through the one or more first introduction holes  143 . The first plate  141  may further include an air guide  146  to guide the air provided to the combustion chamber C toward a flame generated from burner  110  and thus increase a contact time between the air and the flame. 
     The air guide  146  may protrude from first plate  141  to a rear side thereof. That is, a part of the first plate  141  may be formed so that air guide  146  protrudes from first plate  141  toward rear wall  35  of frame  21 . The air guide  146  may include a curved portion  146   a , and linear portions  146   b  and  146   c  which are located at one end or both ends of the curved portion  146   a . Alternatively, the air guide  146  may include only the curved portion  146   a . For example, curved portion  146   a  of air guide  146  may be formed in an arc-like shape. A radius of curved portion  146   a  may be larger than that of second reinforcing part  153 . Therefore, at least a part of curved portion  146   a  may be disposed between second reinforcing part  153  and first reinforcing parts  144 . The distance from a center of first opening  142  to curved portion  146   a  may be smaller than a radius of an inner circumferential surface of burner  110 . Therefore, the air introduced into the combustion chamber C may be guided toward the flame of burner  110  by air guide  146 . The air guide  146  may be integrally formed with first plate  141 , or may be attached to first plate  141 . 
     A cross section of the air guide  146  may be rounded to smoothly guide a flow of the air. 
     Meanwhile, one or more first fastening holes  150  to which second cover  160  is attached by the fastening member may be formed at first fastening part  149 . 
       FIG. 8  is a perspective view of the 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 . 
     Referring to  FIGS. 4, 5, 8 and 9 , the second cover  160  may include a second plate  161 . The second cover  160  may further include a second extension part  165  which extends from second plate  161  toward a front side thereof, and a second fastening part  166  which is bent from second extension part  165 . 
     The second plate  161  may include a second opening  162  through which the air heated in the combustion chamber C is discharged. The second opening  162  may be formed in a circular shape, but is not limited thereto. A diameter of second opening  162  may be smaller than that of first opening  142 . 
     The second plate  161  may further include a burner fastening hole  170  to which burner  110  is attached. Also, second plate  161  may further include one or more protruding portions  164  which prevent the burner  110  from being directly in contact with second plate  161 . 
     The one or more protruding portions  164  may protrude toward burner  110 , when burner  110  is installed at second plate  161 . That is, a portion of the second plate  161  may be formed so that the one or more protruding portions  164  protrude toward burner  110 . 
     For example, the one or more protruding portions  164  may be in contact with burner  110 . As another example, the one or more protruding portions  164  may be adjacent to burner  110  and spaced apart from burner  110 , and then may be in contact with burner  110 , when an external force is applied to burner  110  or the second plate  161  is deformed (e.g., heat deformation). Accordingly, burner  110  may be prevented from being directly in contact with second plate  161  by the one or more protruding portions  164 . Also, because second plate  161  includes the one or more protruding portions  164 , thermal deformation of the second plate  161  may be minimized. 
     When burner  110  is installed at second cover  160 , and first cover  140  is attached to second cover  160 , burner  110  is spaced apart from first plate  141  of first cover  140  and second plate  161 . Accordingly, the air outside frame  21  that is supplied into the combustion chamber C may flow between first plate  141  and burner  110  and between second plate  161  and burner  110 . 
     When second plate  161  includes a plurality of protruding portions  164 , plurality of protruding portions  164  may be overlapped with burner  110  in a forward and backward direction when burner  110  is installed at second cover  160 . The second plate  161  may further include one or more stabilizer fastening holes  163  to which the stabilizer  180  is attached. 
     The second fastening part  166  may include one or more second fastening holes  169  to which the fastening member passed through first fastening hole  150  of first fastening part  149  is attached. 
     According to another embodiment of the invention, first cover  140  and second cover  160  may not include first fastening part  149  and second fastening part  166 , but first extension part  148  of first cover  140  and second extension part  165  of second cover  160  may be attached to each other by the fastening member. 
     The second cover  160  may further include a second insertion part  167  which passes through bottom wall  32  of frame  21 . One or more second introduction holes  167   a  may be provided at second insertion part  167 . Therefore, the one or more second introduction holes  167   a  may be located outside frame  21 . Accordingly, air outside of the frame  21  may be supplied to the combustion chamber C through the one or more second introduction holes  167   a.    
     When first cover  140  is attached to the second cover  160 , at least a part of first insertion part  151  of first cover  140  may be spaced apart from second insertion part  167  of second cover  160 . 
       FIG. 8  illustrates an example in which a plurality of second introduction holes  167   a  are arranged to be horizontally spaced apart from each other. It is understood that the invention is not limited to any particular number, arrangement, and/or shape of the second introduction holes  167   a.    
     According to the embodiment, the air outside frame  21  may be smoothly introduced into the combustion chamber C by the one or more first introduction holes  143  provided at first cover  140  and one or more second introduction holes  167   a  provided at second cover  160 . 
     The second cover  160  may further include one or more installation parts  168  for installing second cover  160  at rear wall  35  of frame  21 . It is understood that the invention is not limited to the one or more installation parts  168  being provided at the second plate  161 . 
     Therefore, when second cover  160  is installed or provided at rear wall  35  of frame  21  by installation parts  168 , second plate  161  may be spaced apart from rear wall  35  of frame  21 . The fan  210  may be disposed in a space between second plate  161  and rear wall  35  of frame  21 . That is, the fan  210  is disposed at a separate space outside the combustion chamber C that is formed by burner cover  130 . 
     The second cover  160  may further include a burner through-portion  171  through which a part of burner  110  passes. The burner through-portion  171  may protrude from second plate  161  to a rear side thereof, but is not limited to such configuration. For example, second plate  161  may be formed so that burner through-portion  171  protrudes from second plate  161  toward the rear side thereof. 
     A burner through-hole  172  may be provided at burner through-portion  171 . The burner through-hole  172  may be aligned with burner hole  36  formed at rear wall  35  of frame  21 . When second cover  160  is installed or provided at rear wall  35  of frame  21 , burner through-portion  171  may be in contact with rear wall  35  of frame  21 . 
     The heated air passed through second opening  162  of burner cover  130  flows through a space between burner cover  130  and rear wall  35  of frame  21 , and then is discharged to cooking chamber  22  through air discharge port  194  of assembly cover  190 . At this time, when second cover  160  is installed or provided at rear wall  35  of frame  21 , burner through-portion  171  is in contact with rear wall  35  of frame  21 , and thus the heated air may be prevented from being introduced again into the combustion chamber C through burner through-hole  172 . Also, the heated air may be prevented from being discharged to a location outside of frame  21  through burner hole  36  formed at rear wall  35  of frame  21 . 
       FIG. 10  is a view illustrating a state in which the ignition unit is installed or provided at the burner according to an embodiment of the invention.  FIG. 11  is a view illustrating a state in which the ignition unit is separated from the burner.  FIG. 12  is a perspective view of a second bracket which is coupled to the ignition unit. 
     Referring to  FIGS. 10, 11, and 12 , burner  110  may include a burner tube  111  of which both ends are spaced apart from each other. In such embodiment, burner tube  111  may be formed in a non-annular shape. For example, at least a part of burner tube  111  may be formed in a “U” shape, but is not limited thereto. 
     A supply part  120  through which the gas and the air are supplied is provided at a first end  111   a  of burner tube  111 , and a second end  111   b  of burner tube  111  is blocked. The supply part  120  may extend in an inclined manner from first end  111   a  of the burner tube  111 . Therefore, a flow direction of the gas and the air supplied through supply part  120  may be changed at first end  111   a , and then the gas and the air may flow toward second end  111   b  along burner tube  111 . Accordingly, the gas and the air supplied through supply part  120  may flow in burner tube  111  in a single direction. 
     The burner tube  111  may be formed in an overall curved shape, such that the entire burner tube  111  has a curved shape. Alternatively, one or more of first end  111   a  and second end  111   b  of the burner tube  111  may be formed in a linear shape, and the other portions thereof may be formed in the curved shape. 
     The burner tube  111  may include an inner circumferential surface  112  and an outer circumferential surface  113 . A plurality of gas outlet holes  114  and  115  may be provided at inner circumferential surface  112  of burner tube  111 . The plurality of gas outlet holes  114  and  115  may be arranged in a plurality of rows. Each “row” includes a set of gas outlet holes that are arranged in the same direction as an extending direction of burner tube  111 . The plurality of rows of gas outlet holes  114  and  115  may include a plurality of first gas outlet holes  114  and a plurality of second gas outlet holes  115 . 
       FIG. 10  illustrates an example in which gas outlet holes  114  and  115  are provided at inner circumferential surface  112  of burner tube  111  in two rows. It is understood that the number of rows of the gas outlet holes is not so limited. That is, gas outlet holes  114  and  115  may be provided at inner circumferential surface  112  of burner tube  111  in a single row. 
     The gas outlet holes  114  and  115  in one of the rows may be disposed or arranged to be spaced apart from each other in a lengthwise direction of burner tube  111 . The gas outlet holes  114  in one of the rows may be spaced apart from gas outlet holes  115  in the other row. 
     The gas outlet holes  114  and  115  in the adjacent two rows may be arranged in a zigzag method so that interference of the flame occurring at gas outlet holes  114  and  115  in the two rows is prevented; however, it is understood that the invention is not limited to such arrangement. That is, the gas outlet holes  115  in the other row may be disposed at areas corresponding to areas among adjacent gas outlet holes  114  in a single row. 
     When an amount of the mixed gas discharged from the gas outlet holes  114  and  115  is increased, the resulting flame becomes larger. Since second end  111   b  of burner tube  111  is blocked, the mixed gas is accumulates toward second end  111   b . Therefore, when a diameter of each of the gas outlet holes at a side of first end  111   a  is the same as that of each of the gas outlet holes at a side of second end  111   b , the flame of the gas outlet holes at the side of second end  111   b  becomes larger, because the amount of the large amount of mixed gas at the side of second end  111   b.    
     However, in the case of the embodiment, the diameter of each of the gas outlet holes at the side of second end  111   b  may be formed smaller than that of each of the gas outlet holes at the side of first end  111   a  so that an overall size of the flame at gas outlet holes  114  and  115  of the burner tube  111  becomes uniform. 
     Alternatively, based on a line which equally divides a length of burner tube  111 , a diameter of each of the gas outlet holes at a portion including second end  111   b  may be formed smaller than that of each of the gas outlet holes of burner tube  111  including first end  111   a.    
     A radius of inner circumferential surface  112  of burner tube  111  may be larger than that of second opening  162  of second cover  160 . When second opening  162  is formed in the non-annular shape, the radius of inner circumferential surface  112  of burner tube  111  may be larger than a maximum length of second opening  162 . 
     One or more installation parts  126  for installing burner tube  111  at second cover  160  may be provided at burner tube  111 . For example, installation parts  126  may be attached to the second cover  160  by screws or similar fastening structures. It is understood that the invention is not limited to any specific coupling method between installation parts  126  and second cover  160 . 
     When installation parts  126  are attached to second cover  160 , burner tube  111  may be spaced apart from second plate  161  of second cover  160 . 
     The supply part  120  may include a plurality of guides  121  and  122  for alignment with nozzle holder  220 . The plurality of guides  121  and  122  are spaced apart from each other, and air outside the frame  21  may be introduced into supply part  120  together with the gas injected from nozzle holder  220  through a space between the plurality of guides  121  and  122 . The supply part  120  may pass through burner through-hole  172  of second cover  160  and burner hole  36  formed at rear wall  35  of frame  21 . Accordingly, since the plurality of gas outlet holes are formed at the inner circumferential surface of burner  110 , and the air passes through an area formed by the plurality of gas outlet holes, the air in cooking chamber  22  may be sufficiently heated by heat of the flame of burner  110 . 
     Also, because the flame is generated at the inner circumferential surface of burner  110 , a distance between the flames is reduced, as it becomes distant from the gas outlet holes, and thus a phenomenon in which the flame is extinguished due to the flow of the air may be prevented. 
     A relative position of ignition unit  230  with respect to burner  110  may be fixed by a fixing device. For example, ignition unit  230  may be installed at burner  110  by the fixing device. The fixing device may include a first bracket  250  attached to burner  110 , and a second bracket  260  attached to ignition unit  230 . The second bracket  260  may be separably connected to first bracket  250 . Alternatively, second bracket  260  may be directly connected to first bracket  250 , or may be connected to first bracket  250  by a separate connection member. 
     Hereinafter, embodiments in which the second bracket  260  is directly and separably connected to first bracket  250  will be described. 
     For example, first bracket  250  may be attached to a position of burner  110  that is close to supply part  120 . The first bracket  250  may include a burner coupling part  252  that is attached to the burner  110 . For example, burner coupling part  252  may be welded to an outside portion of the burner  110 , or may be attached to a fastening part (not shown) provided at an outside of the burner  110  by, for example, a screw. 
     The first bracket  250  may further include a bracket coupling part  254  to attach with second bracket  260 . The bracket coupling part  254  may be integrally formed with the burner coupling part  252 , or may be attached to the burner coupling part  252 . 
     When first bracket  250  is attached to burner  110 , first bracket  250  may be located between first end  111   a  and second end  111   b  of burner tube  111 . The bracket coupling part  254  may include a first hook  256  for attaching with the second bracket  260 . The bracket coupling part  254  may further include a first fastening hole  255  for attaching with second bracket  260  by a first fastening member  270 . 
     The first hook  256  and first fastening hole  255  may be vertically spaced apart from each other; however, it is understood that the invention is not limited to such arrangement. For example, the first hook  256  may be located above or below first fastening hole  255 . 
     The second bracket  260  may include a first fastening part  261  for attaching with first bracket  250 . 
     The first fastening part  261  may include a hook coupling hole  264  to which first hook  256  is attached. 
     As another example, first hook  256  may be provided at second bracket  260 , and hook coupling hole  264  may be provided at first bracket  250 . 
     The first fastening part  261  may further include a second fastening hole  265  for attaching with first bracket  250  by first fastening member  270 . When first hook  256  of first bracket  250  is attached to hook coupling hole  264 , first fastening member  270  may be attached to second fastening hole  265  and first fastening hole  255 . 
     The hook coupling hole  264  and second fastening hole  265  may be vertically spaced apart from each other; however, it is understood that the invention is not limited to such arrangement. For example, hook coupling hole  264  may be provided above or below second fastening hole  265 . 
     The second bracket  260  may further include a second fastening part  262  for attaching with ignition unit  230 . The second fastening part  262  may be bent from first fastening part  261 . 
     The second fastening part  262  may include a second hook  268  for coupling with the ignition unit  230 . 
     The second fastening part  262  may further include a third fastening hole  267  through which a second fastening member  243  to be attached to the ignition unit  230  passes. 
     The second hook  268  and the third fastening hole  267  may be vertically spaced apart from each other; however, it is understood that the invention is not limited to such arrangement. For example, the third fastening hole  267  may be located above or below the second hook  268 . 
     To prevent interference between first fastening member  270  attached to second fastening hole  265  and second fastening member  243  attached to third fastening hole  267 , second fastening hole  265  and third fastening hole  267  may be disposed at different heights of second bracket  260 .  FIG. 12  illustrates an example in which third fastening hole  267  is located above than second fastening hole  265 . However, second fastening hole  265  may be located above than third fastening hole  267 . That is, first fastening member  270  and second fastening member  243  may have different coupling heights from each other. 
     In the embodiment, a fastening or attaching direction of first fastening member  270  is not limited, but may be a forward and backward direction of cooking chamber  22 . 
     Alternatively, the fastening or attaching direction of first fastening member  270  may be in parallel with a flowing direction of the air passing through first and second openings  142  and  162  of burner cover  130 . 
     The second bracket  260  may further include a third fastening part  263  which is attached to burner coupling part  252  of first bracket  250 . The third fastening part  263  may be bent from second fastening part  262 . The third fastening part  263  may be arranged in parallel with first fastening part  261 , but is not limited thereto. 
     The third fastening part  263  may include a coupling rib  269  which is coupled to burner coupling part  252 . For example, coupling rib  269  may be inserted into burner coupling part  252 . The burner coupling part  252  may include a rib insertion hole  253  in which coupling rib  269  is inserted. 
     The ignition unit  230  may include a fastening guide  240 . The fastening guide  240  may include a hook through-hole  241  through which second hook  268  passes. The fastening guide  240  may include a fourth fastening hole  242  to which second fastening member  243  is attached. 
     When second hook  268  passes through hook through-hole  241 , second fastening member  243  may be attached to fourth fastening hole  242  and third fastening hole  267 . 
     As another example, fastening guide  240  may include second hook, and second bracket  260  may include the hook through-hole through which the second hook passes. 
       FIG. 13  is a view illustrating a state in which the burner having the ignition unit is installed or provided at the burner cover. 
     Referring to  FIGS. 11, 12, and 13 , a part of ignition unit  230  may be located or provided at burner through-portion  171  of burner cover  130 . Alternatively, at least a portion of the fixing device may be located within an area formed by burner through-portion  171  of burner cover  130 . Alternatively, first fastening member  270  attached to first bracket  250  and second bracket  260  may be attached to burner through-portion  171 . Alternatively, first fastening member  270  may be attached to first bracket  250  and second bracket  260  may be attached to burner through-portion  171  and rear wall  35  of frame  21 . Accordingly, since at least a portion of the fixing device is located within the area formed by burner through-portion  171 , a width of burner cover  130  in a forward and backward direction thereof may be reduced or limited. 
     The ignition unit  230  may include an ignition bar  232 . The ignition bar  232  may extend in a vertical direction. The ignition bar  232  is a part which is heated to a high temperature, and the mixed gas may be ignited by being in contact with ignition bar  232 . 
     When ignition unit  230  is installed or provided at burner  110  by the fixing device, ignition bar  232  may be spaced apart from inner circumferential surface  112  of burner  110 . The ignition bar  232  may be located at an area between inner circumferential surface  112  of burner  110  and second opening  162 . 
     The ignition bar  232  may face one or more gas outlet holes  114  and  115  provided at inner circumferential surface  112  of burner  110 . That is, the mixed gas discharged from burner  110  through one or more gas outlet holes  114  and  115  may flow to ignition bar  232 , and thus the mixed gas may be ignited. 
     Hereinafter, a method for assembling the burner assembly and a method for separating the ignition unit according to embodiments of the invention are described. 
     The nozzle holder  220  and fan motor  212  may be installed or provided at rear wall  35  of frame  21  from an outside of frame  21 . When fan  210  is located or provided at a front of rear wall  35  of frame  21 , fan motor  212  may be attached to fan  210 . 
     Also, second cover  160  may be attached to rear wall  35  of frame  21  from an inside of frame  21 . In such arrangement, burner  110  is installed or provided at second cover  160 , and ignition unit  230  is installed at burner  110 . Specifically, second bracket  260  to which ignition unit  230  is attached may be attached to first bracket  250  which is attached to burner  110 . First, when first hook  256  of first bracket  250  passes through hook coupling hole  264  of second bracket  260 , first fastening member  270  may be attached to second fastening hole  265  and first fastening hole  255 . At this time, first fastening member  270  may be attached to each of the first and second fastening holes  255  and  265  in a forward and backward direction of cooking chamber  22 . 
     In such arrangement, first cover  140  is attached to second cover  160 . Assembling of burner assembly  23  is completed when assembly cover  190  is coupled to rear wall  35  of frame  21  from an inside of the frame  21 . To separate ignition unit  230  from cooking device  1 , door  25  may be opened. The assembly cover  190  may then be separated from rear wall  35  of frame  21 , and first cover  140  may then be separated from second cover  160 . 
     The first fastening member  270  may then be released from an attached state. At this time, the attached state of first fastening member  270  may be released in the forward and backward direction of cooking chamber  22 . When the attached state of first fastening member  270  is released, first hook  256  is separated from hook coupling hole  264  of second bracket  260 . Second bracket  260  to which ignition unit  230  is coupled may then be separated from first bracket  250 , and ignition unit  230  may then be removed from the cooking device  1 . If necessary, the coupling between the ignition unit  230  and the second bracket  260  may be released. 
     Accordingly, because a position of ignition unit  230  with respect to the burner located inside the frame  21  may be fixed by the fixing device, the ignition unit  230  can be more easily removed from cooking device  1  when it is necessary to replace or check the ignition unit. 
     Also, when the first bracket coupled to the burner and the second bracket coupled to the ignition unit are coupled to each other by the hook, the first bracket and the second bracket can be coupled using the fastening member, and thus the number of fastening members can be reduced, and also an operation time can be reduced. Also, because an attaching or releasing direction of the first fastening member is in the forward and backward directions of the cooking chamber, the user can more easily couple or release the first fastening member. 
     Also, when the fastening rib of the third fastening part is inserted into the burner coupling part, the first fastening part can be attached to the bracket coupling part by the first fastening member. Accordingly, when the first fastening member is attached, the bracket fastening part can be prevented from being deformed with respect to the burner coupling part. 
       FIG. 14  is a vertical cross-sectional view illustrating a state in which the burner assembly is installed or provided at the frame according to an embodiment of the present disclosure. 
     Referring to  FIG. 14 , a through-hole  32   b  through which the first and second insertion parts  151  and  167  of burner cover  130  pass may be formed at bottom wall  32  of frame  21 . Therefore, as the first and second insertion parts  151  and  167  of burner cover  130  pass through through-hole  32   b , the first and second insertion parts  151  and  167  may be located outside of frame  21 . 
     At least a portion of first insertion part  151  may be spaced apart from second insertion part  167 , and may form a third introduction hole  167   b . The fan  210  is provided at an exhaust path P 1 , which is an external space of the combustion chamber C. The exhaust path P 1  may be formed by an outer surface of burner cover  130 , rear wall  35  of the frame  21 , and assembly cover  190 . 
     Therefore, according to an embodiment of the invention, when the plurality of gas outlet holes  114  and  115  are formed at the inner circumferential surface of burner  110 , and fan  210  is provided at the exhaust path P 1  which is independent from the combustion chamber C, the fan  210  may be prevented from being heated by the flame of the burner  110 . Also, because the air is heated by being in contact with the flame of burner  110  and then flows toward fan  210 , the air may be sufficiently heated by the heat of the flame. 
     Moreover, because the air is heated in the combustion chamber C by the flame generated from the inner circumferential surface of burner  110 , and then flows toward fan  210 , the air may be heated by the flame even when the flame is bent toward the fan  210  by the flow of the air due to rotation or operation of fan  210 . 
     Hereinafter, an operation of the burner assembly will be described according to an embodiment of the invention. 
     When the operation of the burner assembly  23  is started, the gas is injected from nozzle holder  220  to supply part  120  of burner  110 . Then, air A 1  (the air outside the frame) around supply part  120  is supplied to supply part  120  together with the gas. At this time, since a low pressure is formed around the gas supplied to supply part  120 , the air A 1  around supply part  120  is naturally supplied to supply part  120  due to a pressure difference (in a natural ventilation method). 
     Accordingly, when the air is supplied to supply part  120  in the natural ventilation method, the air necessary to burn the gas may not be sufficiently supplied to supply part  120 . In this case, the mixed gas in which the gas and the air are mixed may be incompletely burned in burner  110 , and thus an amount of carbon monoxide may be increased due to the incomplete combustion. 
     However, according to embodiments of the disclosure, because the first and second insertion parts  151  and  167  of burner cover  130  pass through bottom wall  32  of frame  21 , and are located outside of frame  21 , additional air A 2  for burning the mixed gas of burner  110  may be introduced into the combustion chamber C. 
     Also, because the plurality of introduction holes  143 ,  167   a  and  167   b  provided at burner cover  130  are located outside of frame  21 , the additional air A 2  for burning the mixed gas of burner  110  may be introduced into the combustion chamber C. 
     The additional air A 2  introduced into the combustion chamber C may flow toward burner  110 . As described above, because burner  110  is spaced apart from first plate  141  of first cover  140  and second plate  161  of second cover  160 , the air in the combustion chamber C may flow through a space provided between burner  110  and first plate  141  and a space provided between burner  110  and second plate  161 . 
     Therefore, the air introduced into the combustion chamber C may smoothly flow toward first gas outlet holes  114  and second gas outlet holes  115  formed at burner  110 . Accordingly, because the air guide  146  is formed at first cover  140 , the additional air A 2  may be guided toward first gas outlet holes  114  by air guide  146 , and thus the additional air A 2  may be sufficiently supplied to first gas outlet holes  114 . 
     Meanwhile, while the mixed gas is supplied to burner  110 , the mixed gas is ignited by ignition unit  230 , and the flame is generated from burner  110 . When the fan  210  is turned on and rotated, the air in cooking chamber  22  is introduced into the combustion chamber C through air suction port  192  of assembly cover  190 . The air introduced into the combustion chamber C passes through an area formed by inner circumferential surface  112  of burner  110 . The air introduced into the combustion chamber C is heated by the flame generated from burner  110 , and then discharged from the combustion chamber C. The air discharged from the combustion chamber C flows through the exhaust path P 1  provided between second cover  160  and rear wall  35  of frame  21 , and then is discharged into cooking chamber  22  through air discharge port  194  of assembly cover  190 . Accordingly, burner cover  130  separately forms the combustion chamber C, and the combustion chamber C and exhaust path P 1  are partitioned by burner cover  130 . Therefore, air flowing through the exhaust path P 1  may be prevented from being introduced again into the combustion chamber C. 
     It is understood that while first bracket  250  is coupled to burner  110  in the above-described embodiment, first bracket  250  may alternatively be provided at burner cover  130 . For example, first bracket  250  may be attached to second cover  160 , and second bracket  260  may be attached to first bracket  250 . In this case, the position of ignition unit  230  with respect to burner  110  may be fixed by coupling second bracket  260  to first bracket  250 . 
       FIG. 15  is a perspective view of a cooking device according to another embodiment of the present disclosure, and  FIG. 16  is a front view of the cooking device of  FIG. 15  in which a second door is separated. The embodiment is the same as the previous embodiment, except for the number of oven units. 
     Referring to  FIGS. 15 and 16 , a cooking device  2  according to the embodiment may include a plurality of oven units  300  and  400 . The plurality of oven units  300  and  400  may include a first oven unit  300 , and a second oven unit  400  located below first oven unit  300 . The plurality of oven units  300  and  400  may include doors  310  and  410 , respectively. 
     A burner assembly  430  is provided at one or more of the plurality of oven units  300  and  400 . A structure of the burner assembly  430  is the same as that of the burner assembly described above, and thus a description thereof will be omitted. 
       FIG. 16  illustrates an embodiment in which burner assembly  430  is provided at second oven unit  400 . However, it is understood that burner assembly  430  may alternatively be provided at the first oven unit  300 , or at each of the plurality of oven units  300  and  400 . 
     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.