Patent Publication Number: US-2013247779-A1

Title: Oven cooker

Description:
TECHNICAL FIELD 
     The present invention relates to a combustion cooker, and more particularly, to an oven cooker in which heat is transferred through introduction, convection, and discharge of combustion air. 
     BACKGROUND ART 
     A direct-heat cooker (KR0937956 10) has been proposed, in which combustion gas used as a heat source of a cooker is introduced into a cooking chamber through a center region of the cooking chamber and makes direct contact with food, and the food is then heated. 
     A cooking utensil (U.S. Pat. No. 3,987,719) in which combustion gas communication holes are formed in an edge bottom portion of a cooking chamber has been proposed. 
     SUMMARY OF INVENTION 
     Technical Problem 
     In the cooking utensil (U.S. Pat. No. 3,987,719), a combustion gas passage is formed between a combustion gas distribution chamber and a cooking chamber, but a combustion gas outlet port is not separately formed at the cooking chamber, so that combustion gas cannot be smoothly discharged from the cooking chamber which in turn makes it difficult to introduce new combustion gas into the cooking chamber and lowers heat transfer efficiency. If a combustion gas outlet port is formed in the top of a cooking chamber cover to smoothly discharge combustion gas from the cooking chamber, energy efficiency may be lowered because relatively hot combustion gas is discharged too early. 
     In the direct-heat cooker (KR0937956 10) in which a flame introduction passage is formed in a center region of the cooking chamber, hot flames make contact with food, and thus the surface of food may be partially burned. In addition, it is difficult to properly control the temperature of the cooking chamber according to food heating conditions, and the center region of the cooking chamber cannot be used as a space for cooking food. 
     An object of the present invention is to provide an oven cooker in which combustion gas used as a heat source can convect smoothly for efficient heat transfer while the combustion gas is introduced and discharged, thereby keeping the temperature of a cooking chamber uniform, allowing the center region of the cooking chamber to be used as a cooking area, and making it possible to select any of a direct heating method in which food is heated by direct contact with combustion gas and an indirect heating method in which food is heated while not making direct contact with combustion gas. 
     Solution to Problem 
     To achieve the above-described object, the present invention provides a cooker mounted on top of a combustion type heating device used as a heat source, the oven cooker having a combustion gas distribution chamber formed between two walls of a dish-shaped cooker base and a combustion gas distribution unit that are sequentially stacked from a lower side, and a cooking chamber formed above the combustion gas distribution chamber by stacking the combustion gas distribution unit or the cooker base with a cooking chamber cover unit. 
     The cooker includes: a plurality of combustion gas communication ports between the combustion gas distribution chamber and the cooking chamber; and a plurality of combustion gas outlet ports between the cooking chamber and an outside of the cooker, wherein combustion gas convects smoothly in the cooking chamber in a condition that combustion gas introduced into the cooking chamber through the combustion gas communication ports does not collide with combustion gas flowing from the cooking chamber to the outside of the cooker, wherein the cooking chamber cover unit has a dual cover structure including an inner cover and an outer cover, and the inner cover is independently provided or detachably coupled to the outer cover, wherein an convection area between the inner cover and the outer cover communicates with the combustion gas distribution chamber, the combustion gas communication ports, and the outlet ports connected to the outside of the cooker. 
     Advantageous Effects of Invention 
     According to the present invention, the communication ports ( 9 ) and the combustion gas outlet ports ( 10 ) are not overlapped with each other but alternately arranged along a lower edge portion of the cooking chamber, so that inflow of combustion gas and outflow of the combustion gas do not overlap each other or collide with each other in the cooking chamber  200  or the convection area  300  of the cooking chamber cover unit for smooth convection and efficient heat transfer. In addition, since hot combustion gas is introduced into the cooking chamber after the hot combustion gas is uniformly spread in the combustion gas distribution chamber, the temperature of the cooking chamber can be easily controlled. 
     The cooking chamber inner cover can be selectively attached according to cooking conditions, and both the rapid direct heating and hygienic indirect heating are possible. Furthermore, various cooking methods such as normal oven cooking, grill cooking, and low-moisture cooking are possible. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a top perspective view illustrating a cover separated from a vertical sidewall of a combustion gas distribution unit according to an embodiment of the present invention. 
         FIG. 2  is a cut-away view illustrating the cover attached according to the embodiment ( FIG. 1 ) of the present invention. 
         FIG. 3  is an exploded perspective view illustrating a cooking chamber cover unit according to the embodiment ( FIG. 1 ) of the present invention. 
         FIG. 4  is a sectional view illustrating a combustion gas introduction port, a combustion gas distribution chamber, a cooking chamber, and a convection area according to an embodiment of the present invention. 
         FIG. 5  is a cut-away view illustrating a state where a cooking chamber inner cover is not used according to an embodiment of the present invention. 
         FIG. 6  is a bottom cut-way view illustrating a cooker base including a flame reflection plated formed in one piece with the cooker base according to an embodiment of the present invention. 
         FIG. 7  is a bottom cut-away view for illustrating a method of coupling a combustion gas distribution unit with the cooker base according to an embodiment of the present invention. 
         FIG. 8  is a bottom cut-away view for illustrating a method of coupling the combustion gas distribution unit with the cooker base and a detachable flame reflection plate according to an embodiment of the present invention. 
         FIG. 9  is a sectional view illustrating a horizontal sidewall of the combustion gas distribution unit according to an embodiment of the present invention. 
         FIG. 10  is a plan view illustrating a cooker base ( 67 ) corresponding to the horizontal sidewall of the combustion gas distribution unit according to an embodiment of the present invention. 
         FIG. 11  is a top perspective view illustrating the horizontal sidewall of the combustion gas distribution unit according to an embodiment of the present invention. 
         FIG. 12  is a bottom perspective view illustrating the horizontally sidewall of the combustion gas distribution unit according to an embodiment of the present invention. 
         FIG. 13  is a vertical sectional view illustrating the horizontal sidewall of the combustion gas distribution unit according to an embodiment of the present invention. 
         FIG. 14  is an exploded perspective view illustrating the horizontal sidewall of the combustion gas distribution unit according to an embodiment of the present invention. 
         FIG. 15  is a cut-away view illustrating a fluid collection portion and a vertical combustion gas outlet ports of a cooker base according to an embodiment of the present invention. 
         FIG. 16  is a view illustrating exemplary convectional flows when an inner cover is not used according to an embodiment of the present invention. 
         FIG. 17  is a view illustrating exemplary convectional flows when the inner cover is used according to an embodiment of the present invention. 
     
    
    
     
         
         
           
               50 ; combustion gas introduction port 
               100 ; combustion gas distribution chamber 
               200 ; cooking chamber 
               300 ; combustion gas convection area between inner and outer covers of cooking chamber 
               1 ; cooking chamber cover handle 
               2 ; cooking chamber cover unit (cooking chamber outer cover) 
               11 ; cooking chamber window 
               12 ; cooking chamber inner cover fixing part 
               23 ; cooking chamber inner cover 
               24 ; cooking chamber inner cover insertion part 
               25 ; combustion gas barrier walls of cooking chamber inner cover 
               26 ; combustion gas guide barrier walls of cooking chamber inner cover 
               27 ; combustion gas introduction ports of cooking chamber inner cover 
               29 ; coupling guide portion of cooking chamber inner cover 
               3 ; food base 
               8 ; food base grill 
               22 ; supporting protrusion of food base 
               5 ; combustion gas distribution unit 
               7 ; grooves for discharging steam and regulating pressure 
               9 ; combustion gas communication ports 
               18 ; combustion gas contact and distribution portion 
               20 ; combustion gas updraft guide portion 
               21 ; sidewall of combustion gas distribution unit 
               6 ; cooker base 
               4 ; cooker handles 
               16 ; cooker base supporting portion 
               19 ; combustion gas updraft guide portion 
               10 ; combustion gas outlet ports 
               13 ; cooking chamber cover guide portion 
               15 ; coupling guide portion of combustion gas distribution unit 
               14 ; base portion for combustion gas distribution unit and cooking chamber cover 
               30 ; flame reflection plate 
               38 ; combustion gas introduction ports 
               17 ; heat source 
               51 ; horizontal coupling portion of combustion gas distribution unit sidewall 
               52 ; combustion gas distribution unit coupling portion of cooker base 
               53 ; combustion gas updraft guide slope of cooker base 
               54 ; combustion gas updraft guide slope of flame reflection plate 
               55 ; cooker base supporting portion 
               56 ; flame reflection plate 
               57 ; combustion gas introduction ports of cooker base 
               58 ; cooker base coupling portion of flame reflection plate 
               59 ; flame reflection plate coupling portion of cooker base 
               60 ; inner cover ring 
               61 ; combustion gas outlet ports 
               62 ; outer cover 
               63 ; inner cover 
               64 ; food base 
               65 ; combustion gas distribution unit 
               67 ; cooker base 
               68 ; combustion gas introduction ports 
               69 ; combustion gas communication ports 
               70 ; guide barrier walls 
               71 ; combustion gas updraft guide portions 
               72 ; combustion gas distribution unit supporting portions 
               73 ; combustion gas guide portions 
               74 ; combustion gas guide portions 
               75 ; groove for discharging steam and regulating pressure 
               76 ; combustion gas distribution unit sidewall 
               101 ; combustion gas introduction ports 
               102 ; combustion gas communication ports of combustion gas distribution unit 
               103 ; combustion gas distribution unit 
               107 ; food base 
               108 ; outer wall of cooking chamber outer cover 
               109 ; cooking chamber outer cover 
               110 ; combustion gas convection area between inner and outer covers 
               112 ; handles of cooking chamber cover unit 
               113 ; handles of cooker base 
               115 ; cooking chamber inner cover 
               117 ; inner wall of cooking chamber outer cover 
               118 ; cooking chamber outlet ports of cooking chamber distribution unit 
               119 ; cooking chamber cover fixing part 
               120 ; cooking chamber 
               121 ; cooking chamber thermometer 
               122 ; cooking chamber cover fixing part 
               123 ; coupling guide portion for combustion gas distribution unit and cooking chamber cover 
               125 ; cooking chamber distribution unit coupling portion of cooker base 
               127 ; cooker base 
               128 ; cooking chamber pressure regulation hole 
               130 ; combustion gas distribution chamber 
               131 ; cooking chamber cover fixing part 
               132 ; combustion gas outlet ports of cooker base 
               133 ; ports of food base for introducing combustion gas into cooking chamber 
               135 ; combustion gas outlet ports of food base 
               151 ; combustion gas outlet ports of cooker base 
               152 ; combustion gas communication ports 
               153 ; fluid collection portion of cooker base 
               155 ; combustion gas introduction ports of cooker base 
               157 ; cooking chamber cover supporting portion of cooker base 
               158 ; combustion gas distribution unit 
           
         
       
    
     BEST MODE 
     Provided is an oven cooker for use with a combustion type heating device, the oven cooker having a lower combustion gas distribution chamber and an upper cooking chamber that are formed by sequentially stacking a cooker base, a combustion gas distribution unit, and a cooking chamber cover unit (see  FIGS. 13 and 14 ). The oven cooker includes: the cooker base having a plurality of grill-shaped combustion gas introduction ports in a bottom center region thereof and a plurality of combustion gas outlet ports arranged at regular intervals along an edge portion thereof; the combustion gas distribution unit having a dish shape and placed on and stacked and coupled to the cooker base, the combustion gas distribution unit having combustion gas communication ports and outlet ports alternately arranged at up and down positions along an edge portion thereof; a food base placed on top of the combustion gas distribution unit and having combustion gas communication ports and outlet ports arranged along an edge portion thereof at positions corresponding to those of the combustion gas distribution unit; a cooking chamber inner cover detachably placed on top of the food base; an outer cover having a vacuum insulation layer and spaced apart from the inner cover to form a combustion gas convection area; and a thermometer having a sensor inserted through a top center portion of the cover unit for measuring inside temperatures of the cooking chamber. 
     MODE FOR INVENTION 
     A cooker of the present invention will now be described in detail with reference to the accompanying drawings in which exemplary embodiments are illustrated. Parts of the cooker denoted by the same reference numeral may be given different names in order to indicate functions of the parts. 
     Concept of Invention 
     If a direct-heat cooker has a combustion gas outlet port in the top of a cooking chamber cover, relatively hot combustion gas is discharged too early although combustion gas can be smoothly discharged. On the other hand, if no combustion gas outlet port or a small combustion gas outlet port is formed, combustion gas cannot be smoothly introduced and discharged. If a combustion gas introduction port is formed in the bottom center of a cooking chamber, and a combustion gas outlet port is formed in a lower portion of the sidewall of a cooking chamber cover or in an edge portion of a cooking chamber base, combustion gas can flow smoothly but the center region of the cooking chamber cannot be used as a cooking space, and food may easily be burned by contact with relatively hot combustion gas. 
     According to the present invention, communication ports between a combustion gas distribution chamber and a cooking chamber or a convection area, and outlet ports between the cooking chamber or the convection area and the outside of the cooker are alternately arranged along a lower edge portion of the cooking chamber. Therefore, combustion gas flowing upward along the sidewall of the cooking chamber does not overlap or collide with combustion gas flowing down in a center region of the cooking chamber to the outside of the cooking chamber, and thus smooth convection is possible. Furthermore, when an inner cover is attached to an outer cover for cooking in an indirect heating mode, combustion gas can be smoothly introduced into and discharged from the convection area formed between the inner cover and the outer cover, and thus efficient convection is possible. 
     Configuration of Invention 
     The present invention relates to a cooker that can be used on top of a combustion type heating device used as a heat source. The cooker includes a cooker base  6 , a combustion gas distribution unit  5 , and a cooking chamber cover unit  2  that are sequentially stacked to form a lower combustion gas distribution chamber  100  and an upper cooking chamber  200  at neighboring regions. In the cooker, convection occurs in the cover unit  2  shaped like a dome, and the combustion gas distribution unit  100  having a duel dish shape is formed in a lower portion of the cooker. 
     The combustion gas distribution chamber  100  is a space between the cooker base  6  and the combustion gas distribution unit  5  and functions as a passage so that combustion gas introduced through a combustion gas introduction port  50  can be distributed to communication ports  9 . 
     Convection 
     Relatively hot combustion gas rises into the combustion gas distribution chamber  100  through the combustion gas introduction port  50  and is radially spread and distributed to the communication ports  9  while colliding with the bottom surface of the combustion gas distribution unit. After passing through the communication ports  9 , the combustion gas flows in a combustion gas convection area  300  and is then discharged through combustion gas outlet ports  10 . If an inner cover  23  is not used, after passing through the communication ports  9 , the combustion gas rises along the inner surface of the outer cover  2  toward the center of the cooking chamber  200  and flows down to heat food, and is then distributed radially and discharged through the combustion gas outlet ports  10 . 
     Cooker Base 
     The cooker base  6  forms a bottom wall of the combustion gas distribution chamber  100 . In a direction from center to periphery, the cooker base  6  includes the combustion gas introduction port  50 , a cooker base supporting portion  16 , a cooking chamber cover base portion  14  having the combustion gas outlet ports  10  and configured to support the combustion gas distribution unit and the cooking chamber cover unit, and a cooking chamber cover guide portion  13 . 
     A combustion gas updraft guide portions  19  ( 71 ), a combustion gas distribution unit coupling guide portion  15 , combustion gas guide portions  73  and  74 , and combustion gas distribution unit supporting portions  72  may be formed depending on a sidewall structure and a coupling method of the combustion gas distribution unit and the cooker base. 
     The combustion gas updraft guide portion  19  ( 71 ) of the cooker base  6  may be connected to an inner or outer side of the cooking chamber cover base portion  14  in a radially alternating manner. 
     The combustion gas distribution unit coupling guide portion  15  may face a combustion gas distribution unit sidewall  21 . 
     Combustion Gas Introduction Port 
     The combustion gas introduction port  50  is formed in the center of the cooker base. The combustion gas introduction port  50  may have a simple communication hole shape, or a flame reflection plate  30  and a grill  38  may be provided at the combustion gas introduction  50  (see  FIG. 7 ). Alternatively, a plurality of small combustion gas introduction ports may be formed in a grill structure (see  FIG. 10 ). 
     Combustion gas introduction ports  68  may be formed in a grill structure in the center region of the cooker base so as to prevent tilting of the cooker when the cooker is not placed on the center of a heat source. Combustion gas guides and reflection plates may be provided on the combustion gas introduction ports, respectively, and in this case, flow directions of combustion gas can be controlled by adjusting the directions of the combustion gas guides and the reflection plates. 
     For the case where the cooker is used on top of a heat source such as a radiation type halogen lamp electric heater, the bottom side of the cooker base may be flat for reliable contact with the heat source. 
     Cooker Base Supporting Portion 
     The cooker base supporting portion  16  functions as a supporting portion for the cooker base and the cooker and forms the bottom wall of the combustion gas distribution chamber. Radial grooves may be formed on the cooker base supporting portion  16  so that the cooker can be exactly placed on the center region of a heat source. 
     Combustion Gas Outlet Ports 
     The combustion gas outlet ports  10  are necessary for facilitating introduction of combustion gas into the cooking chamber, and for the case where the inner cover is attached, the combustion gas outlet ports  10  may be formed in the cooking chamber cover base portion  14  at positions outside the inner cover. Instead of forming the combustion gas outlet ports  10 , the outer cover  2  and the cooking chamber cover base portion  14  may be configured in a manner such that the outer cover  2  and the cooking chamber cover base portion  14  are spaced apart from each other at regularly-spaced portions thereof. Additional combustion gas outlet ports that can be adjusted in open areas may be formed in the outer cover  2 . 
     The combustion gas outlet ports are formed in a vertical or horizontal edge portion of the cooker base and are arranged alternately with the communication ports formed between the combustion gas distribution chamber and the cooking chamber. 
     The combustion gas outlet ports for discharging combustion gas from the cooking chamber or the convection area to the outside of the cooker may be arranged at regular intervals along the edge portion of the combustion gas distribution unit or the cooker base located at a lower edge portion of the cooking chamber. Alternatively, in the embodiment where contact regions and gap regions are alternately arranged between the edge portions of the cooker base and the combustion gas distribution unit, the combustion gas outlet ports may be formed at the contact regions through the cooker base and the combustion gas distribution unit. 
     Cooking Chamber Cover Guide Portion 
     A guide portion may be additionally formed at an edge portion of the cooker base for guiding the cooking chamber cover. 
     In an embodiment (see  FIG. 8 ) where horizontal coupling portions are formed on a horizontal sidewall (see  FIG. 11 ) and the sidewall of the combustion gas distribution unit  5 , the cooking chamber cover guide portion also functions as a coupling guide portion for the combustion gas distribution unit  5 . 
     Combustion gas outlet ports may be formed in the cooking chamber cover guide portion which is formed on the edge portion of the cooker base. 
     Another cooking chamber cover guide portion may be formed on an edge portion of the combustion gas distribution unit or a food base, and additional handles may be formed on the cooking chamber cover guide portion. 
     Cooking Chamber Cover Base 
     The cooking chamber cover base portion is formed between the cooking chamber cover guide portion and the cooker base supporting portion or the combustion gas updraft guide portion. The cooking chamber cover base portion may have a doughnut shape for the vertical sidewall  21  or may be provided in the form of projects regularly spaced and aligned with portions where combustion gas outlet ports are formed. 
     That is, the cooking chamber cover base portion may be shaped or arranged according to the shape of the combustion gas distribution unit and whether the combustion gas distribution unit is attached or not. The cooking chamber cover base portion may be provided at the edge portions of the cooker base, the combustion gas distribution unit, and the food base. 
     Cooker Handles 
     Cooker handles  4  are coupled to portions of the cooker base  6 . For example, at least one cooker handle  4  may be coupled to the outside of the cooking chamber cover guide portion  13  or a lower face of the cooking chamber base portion  14 . For example, two cooker handles  4  may be symmetrically coupled. 
     Combustion Gas Distribution unit 
     The combustion gas distribution unit  5  forms a top wall of the combustion gas distribution chamber  100  and also a bottom wall of the cooking chamber  200 . The combustion gas distribution unit  5  includes a dish-shaped horizontal portion  18  and a sidewall  21  ( 76 ), and the combustion gas communication ports  9  ( 69 ) and external grooves  7  ( 75 ) for discharging steam and regulating pressure are formed in the sidewall  21 . 
     In an embodiment where concave-convex portions are not formed on the edge portion of the cooker base (see  FIG. 14 ), concave-convex portions may be alternately formed horizontally along the edge portion of the combustion gas distribution unit as communication ports between the combustion gas distribution chamber and the cooking chamber and combustion gas outlet ports for discharging combustion gas from the cooking chamber. That is, concave-convex portions may be alternately formed along the edge portion of the combustion gas distribution unit as combustion gas communication ports between the combustion gas distribution chamber and the cooking chamber or the convection area and combustion gas outlet ports for discharging combustion gas from the cooking chamber or the convection area. In the embodiment (shown in  FIG. 14 ), the edge portion of a food base  107  may extend so as to be overlapped with the edge portion of the combustion gas distribution unit, and communication ports thereof may be aligned. 
     In a state where the inner cover  23  is coupled, the combustion gas distribution unit  5  functions as a barrier wall covering the inner cover  23  and the cooking chamber  200  and preventing introduction of combustion gas into the cooking chamber. 
     Combustion Gas Distribution Wall 
     A combustion gas distribution wall  18  may have a flat disc shape, a dish shape with an upwardly or downwardly sloped edge portion, or a concave-convex barrier wall shape. 
     In an embodiment in which a center portion of the combustion gas distribution protrudes upward for the case where the food base is not provided, fluid exuding from food may flow to the edge portion of the distribution unit and may be then collected on the cooker base through communication ports. In an embodiment where the food base has a shape similar to that of the combustion gas distribution unit (see  FIG. 15 ), fluid exuding from food may flow along a sloped face to an exuding fluid collection portion of the cooker base. 
     The combustion gas distribution wall  18  may have a combustion gas updraft guide portion  20  which is not an essential portion but helps combustion gas to rapidly flow from center to side portion of the combustion gas distribution chamber  100 . A spiral protrusion may be formed on the bottom surface of the combustion gas distribution wall to induce swirling of combustion gas. 
     Flame Reflection Plate 
     A flame reflection plate ( 30 ,  56 ) may be provided to prevent the combustion gas distribution wall  18  from making direct contact with combustion gas and excessively increasing in temperature. A protruded central flame reflection plate  30  may be formed in one piece with the cooker base  6 , or a flame reflection plate  56  may be detachably coupled to a center portion  59  of the cooker base. A guide portion may be formed on the flame reflection plate to control the inflow direction of combustion gas, and the guide portion may have a spiral shape to induce swirling flows. 
     Combustion Gas Communication Ports 
     The communication ports  9  ( 69 ) are formed in the edge-portion sidewall  21  of the combustion gas distribution unit  5  at positions facing a space between the combustion gas distribution unit and the cooker base. The communication ports  9  are radially arranged alternately with the combustion gas outlet ports  10  that are regularly arranged along the contact between the combustion gas distribution unit and the cooker base. Combustion gas flows from the combustion gas distribution chamber  100  to the cooking chamber  200  or the convection area  300  through the communication ports  9 , and since the communication ports  9  and the combustion gas outlet ports  10  are not aligned with each other but are alternately arranged, the combustion gas introduced into the cooking chamber or the convection area from the combustion gas distribution chamber does not flow directly to the combustion gas outlet ports but flows upward to transfer heat by convection and is then discharged. The present invention is characterized by this flow of combustion gas. 
     The combustion gas communication ports between the combustion gas distribution chamber and the cooking chamber or the convection area are arranged at regular intervals along the edge portion of the combustion gas distribution unit located at the lower edge portion of the cooking chamber. In the case where contact regions and gap regions are alternately arranged between the edge portions of the cooker base and the combustion gas distribution unit, combustion gas may flow from the combustion gas distribution chamber to the cooking chamber or the convection area through the gap regions and the communication ports. In this case, the gap regions may function as communication ports  152 . The contact regions and the gap regions may be arranged alternately (see  FIGS. 11 and 14 ), side by side at inner and outer positions or upper and lower positions (see  FIGS. 1 ,  7 , and  8 ) along the lower edge portion of the cooker. 
     Sidewall of Combustion Gas Distribution unit 
     The sidewall  21  ( 76 ) which is an edge portion of the combustion gas distribution unit  5  has the communication ports  9  ( 69 ) that are radially arranged at regular intervals at coupling positions between the stacked cooker base  6  and the outer cover  2  ( 23 ). 
     At least a portion of the edge-portion sidewall  21  may make contact with the horizontal cooker base  6  as a horizontal contact portion, and combustion gas outlet ports may be arranged at regular intervals on the horizontal contact portion (see  FIG. 9 ) or outlet ports and communication ports may be arranged radially and alternately (see  FIG. 13 ). 
     In an embodiment where a vertical sidewall and a horizontal sidewall are coupled (see  FIG. 9 ), combustion gas communication ports may be formed in the vertical sidewall, and combustion gas outlet ports may be formed in the horizontal sidewall. 
     To make the cooking chamber inner cover simple, combustion gas communication ports and outlet ports may be alternately arranged side by side in the horizontal sidewall (see  FIG. 11 ). 
     Horizontal Sidewall of Combustion Gas Distribution unit 
     The communication ports for introducing combustion gas into the cooking chamber and the outlet ports are alternately arranged side by side along the horizontal sidewall so that combustion gas can be introduced into and discharged from the cooking chamber in vertically opposite directions, and when the inner cover is coupled, smooth convection is possible during introduction and discharge of combustion gas. In the embodiment, guide walls ( 71 ,  73 ,  74 ) are formed on the edge portion of the cooker base for guiding flows and distribution of combustion gas, and thus combustion gas flowing in a horizontal direction can smoothly rise toward the cooking chamber. 
     The combustion gas distribution unit supporting portions  72  are arranged horizontally and radially along the edge portion of the cooker base to support the combustion gas distribution unit, and combustion gas outlet ports  61  are formed in each of the combustion gas distribution unit supporting portions  72 . 
     The horizontal sidewall of the combustion gas distribution unit may have a constant height, or may have an alternate concave-convex shape so that the communication ports and the outlet ports have different heights. In this embodiment, a concave-convex portion may not formed on the edge portion of the cooker base. 
     Hole for Discharging Steam and Regulating Pressure 
     When cooking food with the inner cover  23  being attached, it may be necessary to discharge steam generated from the food and regulate the inside pressure of the cooking chamber caused by temperature changes, and thus a communication hole may be formed, as a passage from the inside of the cooking chamber  200  to the outside of the cooker, in a side of the inner cover  23  or in at least one of the sidewall  21  ( 76 ) of the combustion gas distribution unit and the inner cover  23  at a contact position between the sidewall  21  ( 76 ) and the inner cover  23 . Instead, a gap between the inner cover  23  ( 63 ) and the sidewall  21  ( 76 ) may have the same function. 
     Since steam and gas generated from the inside of the cooking chamber may include foul and smell particles, the hole for regulating pressure may be positioned such that smell particles or fat particles can be decomposed by head of combustion gas rising after being discharged from the combustion gas distribution chamber to the convection area. 
     In an embodiment where the inner cover and the outer cover are coupled (see  FIG. 13 ) and a thermometer is inserted in a coupling portion of the cover unit, a pressure regulation communication hole may be formed between a thermometer insertion sensor and the coupling part, and a pressure regulation hole may be formed to connect the cooking chamber and the convection area or connect cooking chamber to the outside of the cooker. 
     Cooking Chamber Cover Unit 
     The cooking chamber cover unit  2  forms the top and lateral walls of the cooking chamber  200 , and the inner cover may be detachably coupled to the outer cover  2  or may be independently provided. 
     The inner cover is placed on and connected to the sidewall  21  ( 76 ) of the combustion gas distribution unit. The inner cover includes combustion gas introduction ports  27  in an contact portion with the sidewall  21  at positions corresponding to the communication ports  9 . A space between the inner cover  23  and the outer cover  2  is the convection area  300 . The combustion gas introduction ports  27  may be formed in a lower end portion of the inner cover making contact with the vertical sidewall  21  at positions corresponding to the communication ports  9 . For the edge portion of the horizontal sidewall  76 , the inner cover may have a horizontal portion in which introduction ports and outlet ports are formed so that vertical barrier walls  70  can be stably supported and placed in exact positions. However, the inner cover may not have the horizontal portion. 
     The outer cover  2  may include at least one layer formed of a material having low heat conductivity, or may have a dual wall structure having a vacuum or air layer or an insulation layer for effective heat transfer from combustion gas to the inside of the cooking chamber. 
     An additional handle or a ring  60  may be coupled to the outer surface of the inner cover, and after cooking, the inner cover can be moved by hooking the ring with a hook instead of holding the ring  60  with a hand so as not to be burned because the ring  60  may be hot. 
     In an embodiment in which the inner cover and the outer cover are coupled, a coupling tube may be inserted in top center portions of the inner and outer covers, and a cooking chamber thermometer and a cooking chamber pressure regulation hole may be included in the coupling tube. Vertical or spiral protrusions may be formed on the inner surface of the outer cover in order to stably hold the inner cover and smoothly guide convection of combustion gas. 
     When cooking food with the inner cover  23  ( 63 ) coupled, the inside of the cooking chamber is little dried so that the food man be cooked by a low-moisture cooking or steaming method, and since the top, bottom, and lateral walls of the cooking chamber can be simultaneously heated, the temperature distribution of the inside of the cooking chamber may be uniform for preventing the food from being locally burned. That is, the entire region of food may be uniformly cooked at a relatively high temperature for good tastes. 
     After detaching the inner cover and the food base, a cooking utensil such as a pot or a baking frame may be placed in the cooking chamber for cooking food by various oven cooking methods. 
     Guide Barrier Walls 
     Guide barrier walls  25  ( 26 ,  70 ) may be formed to partially separate the communication ports from the outlet ports in the convection area so that combustion gas introduced into the convection area through the communication ports can flow to the outlet ports after flowing through the convection area. The guide barrier walls may also function as positioning and spacing barrier walls when the inner cover and the outer cover are coupled to each other. The guide barrier walls may be sloped to induce swirling of combustion gas. 
     Cooking Chamber Window 
     A window may be formed in at least a portion of the cooking chamber cover  2  ( 23 ) so that the state of food can be checked without opening the cooking chamber cover  2 . 
     At least one cooking chamber cover handle  1  may be coupled to the outside of the cooking chamber cover. 
     Cooking Chamber Thermometer 
     Since the temperature of the cooking chamber is the most important condition in oven cooking, it may be necessary to measure the temperature in real time. A communication port for a cooking chamber thermometer may be formed in the cooking chamber cover, and a probe of the cooking chamber thermometer may be inserted in the communication port for measuring the inside temperature of the cooking chamber in real time. 
     An insertion port for a temperature sensor may be formed in an inner cover coupling portion  119  for a simple structure, and an inner cover coupling portion thermometer insertion hole may also be formed in a top center portion of the cooking chamber cover. 
     A combustion gas or steam outlet port variable according to measured temperatures of the cooking chamber and a temperature set at the cooking chamber thermometer may be formed in the cooking chamber cover so as to cook food stably at a constant temperature under feedback temperature control. 
     Food Base 
     At least one of the food base  3  and a food base grill  8  may be provided for preventing the bottom of the cooker from being contaminated by fluid exuding from food during cooking, preventing food from being burned by direct contact with the hot bottom of the cooker, effectively separating fluid exuding from food, and inducing smooth convection around food. 
     If necessary, a food base  107  may include a horizontally extended edge portion in which combustion gas communication ports such as ports  133  for introducing combustion gas into cooking chamber and outlet ports  135  for discharging combustion gas from the cooking chamber are formed at positions corresponding to communication ports  102  and  108  of a combustion gas distribution unit  103 . 
     In an embodiment (see  FIG. 14 ), concave-convex edge portions ( 102 ,  108 ) of the combustion gas distribution unit  103  are flat and not exposed so that the cooking chamber cover can be easily placed thereon and the external appearance can be improved. In the embodiment (see  FIG. 14 ), the food base and the combustion gas distribution unit are spaced apart from each other, and thus an additional lower protrusion is not necessary. 
     The edge portion of the food base may be extend to the edge portion of the combustion gas distribution unit, and combustion gas communication holes may be formed in the overlapped portions thereof (see  FIG. 14 ). In this case, the edge portion of the food base can be used as a cooking chamber cover base. 
     Various additional bases may be used for adjusting the contact area between the combustion gas distribution unit and the food base according to cooking methods or purposes, and controlling the rate of heat transfer. 
     Passage for Collecting and Discharging Fluid Exuding From Food 
     Fluid exuding from food flowing on the top surface of the food base or the combustion gas distribution unit is guided to an inner collection area or discharged to an outer side. Discharged fluid may flow to a fluid collection portion of the food base or may be discharged from the cooker to the outside of the container through a part of combustion gas communication ports. 
     Shape 
     The horizontal section of the cooker may be circular. However, the horizontal section of the cooker may have an elliptical, rectangular, or polygonal shape. 
     For the case of cooking a large amount food at a time, a rectangular horizontal sectional shape may be advantageous for efficiently using space. 
     The combustion gas distribution unit and the food base may have polygonal edge portions so that the combustion gas distribution unit and the food base can be easily coupled to each other at an exact angle. 
     The cooker of the present invention may have a rotatable or symmetric shape. 
     Parts of the cooker may have concave-convex structures so that the parts can be exactly coupled. 
     The communication ports, introduction ports, and outlet ports of the cooker according to the present invention may be multiple grill holes or simple communication holes. 
     The combustion gas introduction port of the cooker base may be large so that the combustion gas distribution unit can be directly placed on a heat source. 
     Parts of the cooker such as the cooking chamber cover, the flame reflection plate and the combustion gas introduction port of the cooker base, the method of coupling the cooker base and the combustion gas distribution unit, the sidewall structure of the combustion gas distribution unit, and the food base may be variously modified and combined in other embodiments. 
     Materials 
     The combustion gas distribution unit  5  and the inner cover may include at least one layer formed of a highly conductive material such as copper, aluminum, and an alloy thereof. The combustion gas distribution unit  5 , the inner surface of the inner cover facing the cooking chamber, and the food base  3  may be coated with a stainless alloy or a material capable of radiating infrared rays such as a ceramic material. 
     At least portions of parts of the cooker of the present invention may be formed of materials such as heat-resistant glass, enamel, ceramics, stones, and crystals, and a metal material may be used for making the cooker owing to simple manufacturing processes. The inner cover  23 , the combustion gas distribution unit  5 , and the food base  3  may include at least one of a material capable of radiating infrared rays and a non-adhesive coating material.