Abstract:
A “rocket” stove that has a plurality of vertical cylindrical cavities containing a combustion chamber, a fuel compartment and a chimney. The vertical cylindrical cavities are connected to a hot-gas chamber where the gases are utilized to heat a hob used in the manner of a griddle. The hob has apertures over the vertical cylindrical cavities, over which the food containers to be heated are placed. The hot-gas chamber has an opening and an exhaust pipe for evacuating the gases from the environment where the stove is used. The stove has a thermal-insulation covering placed between the interior walls thereof and the exterior in order to prevent burns. The exhaust pipe prevents intoxication by smoke inhalation, which commonly arises when cooking over an open fire.

Description:
OBJECT OF THE INVENTION 
       [0001]    The present invention relates to a wood, coal or biomass burning stove, which allows to extract the produced fumes by means of a plurality of combustion chambers communicated with a hot fumes distribution chamber in combination with a chimney, avoiding the health problems associated with poisoning by fumes from cooking over an open fire, allowing the use of the stove in confined spaces. A second object of the invention is to reduce the risk of burns by means of thermal insulation between the outside of the stove housing and its internal elements, where the heat is produced. A third object of the invention is to enable the cooking of food contained in a plurality of containers simultaneously. A fourth object of the invention is to provide a surface that is heated by the fumes produced during the combustion for cooking and heating food, particularly tortillas, using this surface as a griddle, not being necessary to remove food containers from fire. 
       BACKGROUND 
       [0002]    There are wood burning stoves as disclosed in the utility model from China No. CN 2459539, wherein a stove uses wood chips as fuel, having a barrel shape, with an opening at the bottom for air inlet and a chimney at the top. The problem with this stove is having a single burner, allowing the heating of only one container of food at a time and not having the means to harness the heat of the fumes produced by combustion. 
         [0003]    The Chinese utility model No. CN 2434530 discloses a stove consisting of a hollow cylinder whose inner wall has a plurality of holes to allow the escape of fumes, said holes leading to a cavity in the outer wall, which is connected to a chimney. In this case, the fumes produced during combustion are directed into the cavity, to be expelled after through the chimney, so that the cavity retains heat to maintain or raise the heat in the combustion chamber itself and has no means to harness the heat for other purposes such as providing a hot griddle. 
         [0004]    The German document No. DE 20309303 discloses a cylindrical stove with a lower grid accessible through a side door. This stove does not allow its use indoors as the interior of a home because it has no means for directing the fumes produced by the combustion. 
         [0005]    U.S. Pat. No. 5,842,463 discloses a portable cylindrical stove with a fuel rack and a ring of holes for the air intake. This stove is designed to be used outdoors, since it has no means for directing the fumes produced by combustion and consequently does not have the means to harness the heat of such fumes. 
         [0006]    The patent application WO 2011060403 shows a cylindrical stove with a grid on the bottom, similar to those disclosed in the above documents and likewise, it does not have the means for directing the fumes produced by combustion and the heat from said fumes is not harnessed for other functions. 
         [0007]    No documents were found in the prior art showing the use of more than one combustion chamber, or any document showing the implementation of a griddle being heated by harnessing the heat of the fumes produced by the combustion, by means of a fumes chamber. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0008]      FIG. 1  shows a front top perspective view of the stove. 
           [0009]      FIG. 2  shows a front view of the longitudinal section of the pedestals ( 300 ) and the griddle ( 100 ) of the stove. 
           [0010]      FIG. 3  shows a bottom view of the griddle ( 100 ). 
           [0011]      FIG. 4  shows a side view wherein the base ( 500 ) of the stove is depicted. 
           [0012]      FIG. 5  shows a cross section of part of the griddle ( 100 ) and one of the covers ( 102 ), wherein the way the handle ( 105 ) is secured to the cover ( 102 ) by means of a hook ( 108 ) and a rod ( 109 ) is shown. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0013]    The present invention consists of a vertical wood, coal or biomass burning stove, which has been implemented with technical adaptations that make it different from all existing stoves of this type, giving it useful advantages and allowing the user to cook more than one meal at a time, while avoiding the risk of skin burns and poisoning by fumes inhalation, and providing a plate for use by way of a griddle. 
         [0014]    The stove consists of a piece of furniture comprising a prismatic hollow housing, being substantially rectangular or square, wherein its sides are substantially longer than its height. Said hollow housing forms a chamber ( 200 ) for the distribution of hot fumes produced by combustion, which is supported by a plurality of pedestals ( 300 ), said pedestals being preferably cylindrical, wherein combustion takes place and which contain some of the elements of said vertical stove, wherein said pedestals ( 300 ) are located below the hot fumes distribution chamber ( 200 ), adjacent to one or more of the sides of said chamber ( 200 ). Preferably, the inner corners of the hot fumes distribution chamber ( 200 ) are rounded to allow better circulation of hot fumes inside it. 
         [0015]    Behind the pedestals ( 300 ), in the opposite side to them in relation to the center of the hot fumes distribution chamber ( 200 ), there is a base ( 500 ), which supports part of the weight of the stove for added stability and to prevent it to lean to one side, since said pedestals ( 300 ) are placed adjacent to one side of the chamber ( 200 ), the stove would lose balance in the absence of said base ( 500 ). Said base ( 500 ) consists of a rectangular plate bent at its center part to form a vertex ( 501 ) of 90°, wherein one of its sides parallel to said vertex ( 501 ), is fixed to the lower side edge of the chamber ( 200 ) on its side that is opposite to the pedestals ( 300 ) while the other side of the plate, also parallel to the vertex ( 501 ), is fixed to the bases of the pedestals ( 300 ) as shown in  FIG. 4 , forming a cavity ( 502 ) in the bottom of the stove used to store the firewood and allow it to dry. Another function of the cavity ( 502 ) is to store the chimney ( 400 ) sections, which remain unassembled for transportation and distribution of the stove. The surface of the base ( 500 ) is stamped to make it resistant against torsional forces applied to the plate it is formed with. The inner surface of the pedestals ( 300 ) is coated with a thick layer of thermal insulator ( 311 ), preferably ceramic, forming a vertical hollow shaft ( 310 ), it being preferably of cylindrical shape, at the center of the pedestals ( 300 ), which forms a body of air at its top section, and a combustion chamber ( 309 ) and a fuel compartment ( 308 ) at its bottom section, which are basic components of said vertical stove. Ceramic has the function of insulating the heat within the stove, avoiding the risk of skin burns from touching the outside housing of the stove. A person skilled in the art will note that the ceramic may be replaced by any heat insulator capable of withstanding the high temperatures of combustion within the stove. 
         [0016]    The height of the pedestals ( 300 ) is preferably greater than the diameter of its base, to allow the combustion chamber ( 309 ) to have a sufficient volume of air to achieve an efficient combustion. Each pedestal ( 300 ) has a pair of doors ( 301 ,  302 ) on its wall, preferably oriented towards the periphery of the stove, arranged one above the other and adjacent to the pedestal base ( 300 ). The upper door ( 301 ) forms an access to the fuel compartment ( 308 ) at the lower vertical section of the hollow shaft ( 310 ). Said upper door ( 301 ) has on its inner side a coating of heat-resistant thermal insulator ( 311 ), preferably ceramic, having the same thickness as the rest of the thermal insulation inside the pedestal ( 300 ). Thus, by closing the upper door ( 301 ), the heat is retained within the vertical hollow shaft ( 310 ), thus preventing it from being transferred to the material of said upper door ( 301 ), limiting the possibility of skin burns to the user. Inside the pedestal ( 300 ) there is a horizontal grate ( 307 ) placed at a height corresponding to the line between the upper door ( 301 ) and the lower door ( 302 ), in the bottom of the vertical hollow shaft ( 310 ). Each upper and lower door ( 301 ,  302 ) is clamped to its respective pedestal ( 300 ) preferably by means of hinges ( 303 ) fixed to a frame ( 305 ), which in turn is fixed to its corresponding pedestal ( 300 ) by means of screws, rivets or another similar fastening element to secure the frames ( 305 ) to the pedestal ( 300 ). On the side of the frame ( 305 ) opposite that of the hinge ( 303 ) is a latch ( 304 ) for securing the door ( 301 ,  302 ) when closed. The lower door ( 302 ) allows the user to control the air intake to the combustion chamber ( 309 ) and to remove the ashes resulting from combustion, from the bottom of the pedestal ( 300 ). The lower door ( 302 ) can be replaced by other similar element that allows for regulation of air intake and ash removal, such as a sliding window. 
         [0017]    The stove has a fitting to facilitate feeding of fuel, which consists of a tray whose height is equal to the height of the lower edge of the upper door ( 301 ). The stove is powered by solid fuel, which may consist of firewood, coal or branches, twigs, stems, trunks, wooden sticks and other similar elements, called biomass as a whole, either in their natural or processed form. To feed the fuel, the tray is positioned in front of the upper door ( 301 ), said upper door ( 301 ) is opened and the pieces of firewood, coal or biomass, which make up the fuel, are introduced in the fuel compartment ( 308 ) through said upper door ( 301 ) towards the combustion chamber ( 309 ), while the tray holds the pieces of wood, coal or biomass in a horizontal position. The grate ( 307 ) keeps the solid fuel within the fuel compartment ( 308 ) while allowing the air intake from beneath it towards the combustion chamber ( 309 ). Once the fuel has been consumed and it has generated ashes, said ashes slide towards the bottom of the pedestal ( 300 ) through the slits of the grate ( 307 ) to allow its removal through the lower door ( 302 ). When igniting the fuel and while it is burning, it is necessary to push the pieces of wood, coal or biomass into the combustion chamber ( 309 ) until they are entirely consumed. Once all of the fuel has been introduced into the fuel compartment ( 308 ), the upper door ( 301 ) is closed to reduce the air intake to the combustion chamber ( 309 ), thus reducing the speed of combustion while keeping the heat within the stove. The upper door can be left open after the fuel has been consumed, at user discretion, without affecting the operation of the stove. The lower door ( 302 ) is used to regulate the air intake to the combustion chamber ( 309 ), so that when fully open ( 302 ), the most amount of air enters into the combustion chamber through the slits of the grate ( 307 ) and therefore, the fuel is burnt more rapidly achieving a higher temperature, heating the interior of the oven over the shortest period of time. Conversely, by moving the bottom door ( 302 ) at lower degrees of openness, less air enters to the combustion chamber ( 309 ) and therefore, the fuel burns more slowly, heating the interior of the stove for a longer period of time, but reaching a lower temperature. 
         [0018]    In another embodiment of the invention, the grate ( 307 ), the upper door and the lower doors ( 301 ,  302 ), can be dispensed with, wherein there is only one entrance to feed the fuel into the fuel compartment ( 308 ) with the disadvantage of not being able to regulate the air intake to the combustion chamber ( 309 ), preventing the control of temperature and combustion time. In this embodiment, the tray has a height equal to that of the lower edge of said entrance for the feeding of fuel. 
         [0019]    The hot fumes distribution chamber ( 200 ) has a plurality of holes ( 201 ) at its base, each one located in correspondence with one of the vertical hollow shafts ( 310 ) of the pedestals ( 300 ) and positioned concentrically with said vertical hollow shafts ( 310 ). The bottom and inner sides of the hot fumes distribution chamber ( 200 ) are coated with a layer of thermal insulation ( 311 ), preferably ceramic, to keep the heat inside the hot fumes distribution chamber ( 200 ) and to prevent the heating of the outside housing of the stove. The holes ( 201 ) at the base of the hot fumes distribution chamber ( 200 ) also pass through said layer of thermal insulation ( 311 ) so that the vertical hollow shafts ( 310 ) and the interior of the hot fumes distribution chamber ( 200 ) are connected through said holes ( 201 ) and the hot fumes produced in the combustion chamber ( 309 ) climb up through the vertical hollow shaft ( 310 ) and are transferred through said holes ( 201 ) into the hot fumes distribution chamber ( 309 ). This can be seen from the longitudinal section shown in  FIG. 2 . 
         [0020]    The top cover of the hot fumes distribution chamber ( 200 ) consists of a griddle ( 100 ) preferably made out of a material with high thermal conductivity which serves as a heat exchanger for the stove. Said griddle ( 100 ) has a plurality of openings ( 101 ) through its surface, disposed each one in correspondence with each of the vertical hollow shafts ( 310 ) in each of the pedestals ( 300 ), concentric thereto, so that heat produced in the combustion chamber ( 309 ) climbs up through the vertical hollow shaft ( 310 ), entering the hot fumes distribution chamber ( 200 ) just below the openings ( 101 ). The griddle ( 100 ) has a slope surrounding the rims ( 106 ) of the openings ( 101 ), on its upper surface. Each opening ( 101 ) has a loose lid ( 102 ) made out of a material with high thermal conductivity, preferably the same material as the griddle ( 100 ), in the same shape of the opening ( 101 ) and larger in size thereto, so that it rests on the rim ( 106 ) of the griddle ( 100 ) located around said opening ( 101 ), engaging the slope of the rim ( 106 ). In the center of the lid ( 102 ), it has a concavity ( 103 ) with a horizontal bar ( 108 ) in its center spaced from the bottom of said concavity ( 103 ), wherein a hook ( 109 ) is inserted, holding said bar ( 108 ) without getting permanently affixed thereto. Said hook ( 109 ) is held by a handle ( 105 ), wherein said handle ( 105 ) serves to grip said lid ( 102 ) and to uncover the opening ( 101 ) of the griddle ( 100 ) without touching said lid ( 102 ) or the griddle ( 100 ), by inserting the hook ( 109 ) in said concavity ( 103 ) to grip the lid ( 102 ) by means of the bar ( 108 ) in the center of said concavity ( 103 ) and thereby being able to lift said lid.  FIG. 5  shows clearly how the hook ( 109 ) is inserted into the concavity ( 103 ). 
         [0021]    To cook food, the opening ( 101 ) is uncovered and a container with food, having a diameter larger than the diameter of said opening ( 101 ), is placed on the griddle ( 100 ) directly over said opening ( 101 ), so that said container is resting on the surface of the griddle ( 100 ), above the opening ( 101 ) and the heat produced in the combustion chamber ( 309 ) climbs up through the vertical hollow shaft ( 310 ), entering the hot fumes distribution chamber ( 200 ) just below the container, heating the base of the container directly, which in this case replaces the griddle ( 100 ) as a heat exchanger to the food inside said container. 
         [0022]    The griddle ( 100 ) has an exhaust hole ( 104 ) to allow the exit of hot fumes produced in the combustion process from the distribution chamber ( 200 ), said exhaust hole is preferably disposed on the opposite side to that wherein said openings ( 101 ) are placed. On the exhaust hole ( 104 ) there is a pipe disposed vertically, affixed to the griddle ( 100 ) by means of a conical base screwed to said griddle ( 100 ) directly over said exhaust hole ( 104 ). This pipe forms a chimney ( 400 ) to allow for the escape of hot gases from the stove. Said chimney ( 400 ) is comprised of several pipe sections assembled one on the end of the next one. Thus, the hot fumes produced in the combustion chamber ( 309 ) climb up through the vertical hollow shaft ( 310 ) into the distribution chamber ( 200 ) towards the openings ( 101 ) of the griddle ( 100 ), filling said distribution chamber ( 200 ), wherein the heat is transferred to the griddle ( 100 ) and to the bases of food containers where appropriate, thus heating them, to then exit through the exhaust hole ( 104 ) to escape through the chimney ( 400 ). 
         [0023]    The hot fumes within the stove cause a pressure increase inside it. Said pressure would cause the natural behavior in the hot fumes produced by combustion to climb up through the vertical hollow shaft ( 310 ), entering the distribution chamber ( 200 ) and directly reach the exhaust hole ( 104 ) and then quickly leave the stove through the chimney ( 400 ), releasing the pressure produced. However, this natural behavior does not allow the hot fumes to circulate within the distribution chamber ( 200 ), preventing the griddle ( 100 ) to be heated uniformly. 
         [0024]    To get the hot fumes to be distributed in the distribution chamber ( 200 ) before leaving the stove through the chimney ( 400 ), the griddle ( 100 ) has a plurality of long thin moldings ( 107 ) protruding from its lower surface, arranged parallel to each other between the openings ( 101 ) and exhaust hole ( 104 ), so that the leading ends of said moldings ( 107 ) are positioned adjacent the openings ( 101 ) and the trailing ends of the moldings ( 107 ) are positioned adjacent to the edges of the griddle ( 100 ). Said moldings ( 107 ) function as conduits to prevent hot fumes to go directly towards the exhaust hole ( 104 ) and collide instead with the walls of said molding ( 107 ) when the hot fumes enter the distribution chamber ( 200 ), said hot fumes being directed towards the periphery of the distribution chamber ( 200 ), following the path set by said moldings ( 107 ) before finding the way to the exhaust hole ( 104 ) and getting out through the chimney ( 400 ).  FIG. 3  shows the path followed by the flow of hot fumes within the distribution chamber ( 200 ), in a dotted line. This way, the griddle ( 100 ) is heated uniformly all over its surface, allowing the use of said upper surface of the griddle ( 100 ) for cooking and heating food, particularly tortillas, without removing food containers that are being heated over the openings ( 101 ).