Abstract:
A portable outdoor stove is provided which includes a burner primarily comprising an outer and inner pieces bolted tightly to form a small gas/air mixture chamber for accepting and maintaining high pressure gaseous fuel, a wind guard of cylinder shape capable of tightly coupled with a cooking vessel and possessing slot opening of less than 180° toward its top for exhaust outlet, adjustable means for supporting the burner and positioning flame from burner onto bottom of cooking vessel, short or long legs to support the wind guard and the cooking vessel. A protection guard can be put around the first wind guard preventing an operator accidentally touching the wind guard during cooking.

Description:
[0001]      
         [0000]    
       
         
               
             
               
               
               
               
             
           
               
                   
               
               
                 US PATENT DOCUMENTS 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 4,062,341 
                 December 1977 
                 Panzarella 
                 126/41 R 
               
               
                 5,158,067 
                 October 1992 
                 Dutro et al. 
                 126/39 R 
               
               
                 6,234,064 
                 May 2001 
                 Turrel 
                  99/323.9 
               
               
                 6,098,611 
                 August 2000 
                 Filmore 
                 126/50 
               
               
                 D386,936 
                 December 1997 
                 Stone et al. 
                 D7/332 
               
               
                 4,553,524 
                 November 1985 
                 Wheat et al. 
                 126/25 R 
               
               
                 4,353,347 
                 October 1982 
                 Seed 
                 126/41 R 
               
               
                 5,775,316 
                 July 1998 
                 Jones 
                 126/41 R 
               
               
                 4,555,616 
                 November 1985 
                 O&#39;Brien 
                 219/432 
               
               
                 5,044,352 
                 September 1991 
                 Lok 
                 126/39 R 
               
               
                 5,226,406 
                 July 1993 
                 Reynolds 
                 126/39 R 
               
               
                 4,583,941 
                 April 1986 
                 Elperin et al. 
                  41/347 
               
               
                 5,315,983 
                 May 1994 
                 Law 
                 126/216 
               
               
                 3,759,164 
                 September 1973 
                 Robinson 
                  99/413 
               
               
                 4,108,142 
                 August 1978 
                 Barson et al. 
                 126/41 R 
               
               
                 5,992,407 
                 November 1999 
                 Tsai 
                 126/40 
               
               
                 6,439,107 
                 August 2002 
                 Bourgeois 
                  99/340 
               
               
                 6,725,856 
                 April 2004 
                 Barbour et al 
                 126/50 
               
               
                 6,832,607 
                 December 2004 
                 Zhou 
                 126/30 
               
               
                 6,619,280 
                 September 2003 
                 Zhou 
                 126/39 R 
               
               
                   
               
             
          
         
       
     
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an outdoor cook stove utilizing high pressure gaseous fuel, in particular a stove for domestic or industrial gas cooking using bottled gas, and is suitable for round bottom cooking vessels. 
         [0004]    2. Brief Description of the Prior Art 
         [0005]    There are various attempts for outdoor stove manufacturers to accommodate cooking for round bottom vessels such as a wok. Barbecue equipment makers make wok adapter to sit on top of fire grid. However the fire grid is not powerful enough and the entire structure is not efficient enough for wok cooking. Authentic, restaurant quality oriental wok cooking requires a stove capable of generating more than 100,000 BTU in power. Such power is beyond reach of single ring low pressure gas stoves. In commercial and industrial wok cooker, as partially illustrated in U.S. Pat. No. 5,315,983, either multi-rings or multiple jet burners are used to achieve the necessary power. Another drawback of using low pressure gaseous fuel is its stove being more susceptible to wind during outdoor cooking. 
         [0006]    U.S. Pat. Nos. 5,158,067 and 4,062,341 taught outdoor stove construction for wok cooking. However they share several disadvantages that prevent them from reaching high quality oriental cooking. The first is the low pressure gaseous fuel which prevents their stoves from reaching 100,000 BTU in power. The second disadvantage is the low pressure burner which they utilize does not have center flame heating to the bottom of a wok. As with a bowl shape, it is most important to direct the burning flame toward the bottom of a wok for efficient heat transfer. The disadvantage of not using a center flame is in many burner designs, for example U.S. Pat. Nos. 6,234,064, 6,098,611, D386,936, 4,553,524, 4,353,347. The flame coming out from all these burners spread outward, leaving a sizable center portion of the cooking vessel relying on metal conducting heat back to its center. For a wok, this heat conducting downward to its bottom is extremely inefficient. 
         [0007]    Yet another disadvantage of the aforementioned stove constructions is to allow the flame to extend above the wok along its outside surface. Since wok cooking requires an operator to stay closely and maneuver the wok in different ways, the flame coming out can easily burn and hurt the operator. Such examples can be found in U.S. Pat. Nos. 4,062,341, 6,098,611, 5,775,316, 3,759,164, 5,992,407, 6,439,107 and 6,725,856. Because of this reason, the operator is forced to reduce power of the stove to stay safe. For low pressure gaseous stove ranges like in U.S. Pat. Nos. 5,044,352 and 5,226,406, expensive exhaust duct mechanism is built for routing the flame and exhaust away from the operator. 
         [0008]    U.S. Pat. Nos. 6,234,064, 6,098,611, D386,936, 4,555,616, 4,353,347 and 4,108,142 taught to have fixed center burner position with respect to bowl shape cooking vessel. Such fixed position defines fixed heating power distribution to the vessel, forcing the operator to frequently toss foods to various locations in order to receive different heating power. Fixed position between stove and wok greatly restricts the freedom for the operator to tilt and rotate the wok for various food items to receive different flame power, which is necessary when the food items are too fragile to be tossed. 
         [0009]    U.S. Pat. No. 4,583,941 taught a burner construction on how to form flame inwardly around an imaginary cylinder. Although the flame is inwardly directed, it still does not heat the center portion of its cooking vessel. Another drawback is that as required by its inward flame, the burner has a bigger chamber for pre-mixed gaseous fuel and air. This big chamber inevitably reduces the mixture gas pressure and hence the power of the burner. 
         [0010]    U.S. Pat. No. 5,979,428 teaches a retrofitable wind screen for portable stove which is wrapped around the original stove body. This is wrap around wind screen is not study at all to withstand a round bottom vessel. 
         [0011]    U.S. Pat. No. 5,315,983 teaches a two piece support ring structure for supporting a wok cooking vessel on top of a burner cylinder of a cooking range. Between these two pieces of ring structure some windows can be formed on the back of the range for exhaust. U.S. Pat. No. 6,832,607 shows an outdoor cook stove with a wind guard of two windows at its back for flame outlet. The top bars of the windows in both U.S. Pat. Nos. 5,315,983 and 6,832,607 are subjected to high temperature flames and thus are the most vulnerable for damage. Besides, these top bars block the flame to reach the wok underneath surface. This blockage is an efficiency loss. 
         [0012]    It is the objectives of the present invention to overcome aforementioned drawbacks. 
       SUMMARY OF THE INVENTION 
       [0013]    The first objective of the present invention is to utilize high pressure gaseous fuel to achieve highest power for wok cooking with simple burner construction to save cost significantly over traditional high power wok cookers with low pressure gaseous fuel. 
         [0014]    The second objective of the present invention is to construct an outdoor stove with a wind guard ring tightly hosting a wok. A portion of the wind guard has openings close to the wok for directing out the flame and exhaust. To increase cooking efficiency and product life cycle, such openings do not have top bars to block burner flamer from reaching underneath surface of the cooking vessel. It also provides access for burner ignition. This portion is to be positioned away from the operator during operation. The rest portion of the wind guard does not have opening to prevent any flame from extending along its side. The operator is positioned along this side for safe operation. This wind guard defines the heating area to the wok and is sized around 9″-13″ in diameter for commonly available woks. 
         [0015]    The third objective of the present invention is to add a second ring outside the first wind guard to prevent the operator from accidentally touching the hot surface of the first wind guard. 
         [0016]    The fourth objective of the present invention is to construct a stove to give complete freedom to the wok operator. The wok is not required to be fixed in position to the stove. The operator can tilt and move the wok in his/her own will at any time in order to achieve best cooking result. 
         [0017]    The fifth objective of the present invention is to have burner position adjustable within the stove to accommodate both round and flat bottom cooking vessels for optimum heat transfer. 
     
    
     
       DESCRIPTION OF THE PREFERRED EMBODIMENTS 
         [0018]    The invention will now be described in connection with certain preferred embodiments with reference to the following illustrative figures so that it may be more fully understood. 
           [0019]    With specific reference now to the figures in detail, it is stressed that the particular shown are by way of example and for purpose of illustrative discussion of the preferred embodiments of the present invention only. They are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention. The description together with the drawings should make it apparent for those skilled in the art how the several forms of the invention may be embodied in practice. In the drawings: 
           [0020]      FIG. 1  is a prior art showing a two-piece support ring structure for supporting a wok cooking vessel on top of a burner cylinder of a cooking range. The ring structure supports the wok cooking vessel and forms flame windows with top bars. 
           [0021]      FIG. 2  is a prior art showing an outdoor cook stove with a wind guard having flame windows. The wind guard supports a cooking vessel. The flame windows have top bars. 
           [0022]      FIG. 3A  is a perspective view of a first preferred embodiment of an outdoor stove incorporating a high pressure gaseous burner, as well as a wind guard ring and an adjustable metal strip for holding the burner. 
           [0023]      FIG. 3B  is a side elevated view of the embodiment of  FIG. 3A  showing how the burner is bolted on the strip. 
           [0024]      FIG. 3C  is a top view of the embodiment in  FIG. 3A  showing details of the mounting strip and three supporting legs. 
           [0025]      FIG. 4  is a perspective view of a second preferred embodiment of an outdoor stove with a second wind guard ring encircling the first ring of  FIG. 3A . 
           [0026]      FIG. 5  is a perspective view of a third preferred embodiment which incorporates the short leg preferred embodiment of  FIGS. 3A and 3  long legs for form a long leg version. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0027]      FIG. 3A  illustrates an outdoor stove  80  constructed according to the preferred embodiment of the present invention. Although stove  80  is specially designed to handle outdoor cooking using a round bottom cooking vessel, stove  80  is also suitable for flat bottom vessel cooking. Stove  80  includes a preferred converging flame burner  10  of U.S. Pat. No. 6,619,280. Burner  10  is mounted on a metal bar  130  using the same bolt  30 , nut  32  and washer  34 , as in  FIG. 3B . Burner  10  directs its flames inward and upward to a concentrating point. This point can be aligned with the bottom of a wok by metal bar  130 . Metal bar  130  has a horizontal section  134 . In the center of  134  a hole is drilled for bolt  30  to come through, better viewed in  FIG. 3B . Burner  10  is mounted on  134  and position of the venturi pipe  24  can be adjusted horizontally for convenient inlet of gas pipe  70 . Metal bar  130  also includes two vertical sections  132  and  136  at both ends, as viewed in  FIG. 3C . These two vertical sections  132  and  136  have slot openings. For example, vertical  132  has a slot  138 . Two bolts  140 ,  142 , two nuts  150 ,  152  and two washers  160 ,  162  are used to fasten the slot  132  to a supporting ring  100 . Similar construction is done on another side  136 . Vertical positioning of the metal bar  130  along ring  100  is accomplished by adjusting the slots with respect to the bolts. In this way the concentrating flame point can always be adjusted to touch the bottom of various woks and other round bottom vessels. The length of section  134  is about the same as the diameter of ring  100 . 
         [0028]    Ring  100  serves multiple purposes. It can support a wok for cooking. A wok can sit right on ring  100 . The diameter for ring  100  is preferably between 9″ to 13″. Ring  100  is constructed as a cylinder shape to house a wok with minimum gap. After heating the bottom of the wok, the concentrated combustion flame is split up along the wok underneath surface. Because of small gap between wok and ring  100 , the flame is not able to penetrate out of the gap. Instead, it is forced to use windows  120  and  122  for exhaust purpose. It should be noted that  120  and  122  are just slots cut into ring  100 . By putting a wok on top of ring  100 , windows  120  and  122  are formed between the opened slots and underneath surface of the cooking wok. In this way the ring defines the heating area to the wok. And the flame coming out of windows  120  and  122  continues to heat the wok. Since windows  120  and  122  have limited opening on ring  100 , their openings define limited unsafe area for an operator. When an operator is working away from these openings (windows  120  and  122 ), there is no flame coming up along the outer surface of the wok to cause any harm to the operator. 
         [0029]    The total opening angle along ring  100  is preferably less than 180° such that no direct wind can blow through burner  10 . In this way ring  100  serves as a wind guard. Ring  100  also supports metal bar  130  for burner  10 . Four holes are drilled for mounting bolts for slots along  132  and  136 . 
         [0030]    Ring  100  is further supported by three legs  110 ,  112  and  114 . Construction for each leg is similar. A bend at  116  for leg  110  in  FIG. 3B  is to increase its bottom perimeter to enhance stability of the entire stove  80 . Top end  110 A of leg  110  is welded to a lower position of ring  100 . Legs  110 ,  112  and  114  are preferably spread out in 120°. 
         [0031]    To start cooking, high pressure gaseous fuel is supplied through a high pressure regulator. Ejected combustion gas and air mixture from the burner can be ignited by an outdoor igniter through either ring windows  120 ,  122  while a wok is already sitting on top of ring  100 . Alternately, the wok can be temporally moved away for an igniter to ignite the flame through top of ring  100 . 
         [0032]    A second stove embodiment of the present invention is shown generally in  FIG. 4 . Since ring  100  prevents flame from burner  10  to reach the operator on the opposite side of windows  120  and  122 , the heat is trapped within ring  100  for the energy to be transferred to a wok. When burner  10  is adjusted to its upper power range, ring  100  may warm up and be hazardous to touch. Although there is little chance for the operator to touch ring  100  because the operation is accomplished by using wok handles at least half foot away from ring  100 , a second ring  200  can still be added outside of ring  100  to protect ring  100  from being reached. Various mounting technique can be used for ring  200 . Three metal pieces  210 ,  212  and  214  are welded upwardly on legs  110 ,  112  and  114 . Piece  210  and leg  110 , piece  212  and leg  112 , piece  214  and leg  114  together define three junction points for ring  200  to rest on. The height of ring  200  is constructed lower than that of ring  100 , preferably half inch. In this way a wok is still supported by ring  100  and exhaust flame can still come out from windows  120  and  122 . Aforementioned features of ring  100  are preserved. Since ring  200  is not heated by flame from burner  10 , it will remain cool during on-going cooking process. An alternate mounting for ring  200  is to weld it directly on legs  110 ,  112  and  114 . Ring  200  does not need to be solid, it can be perforated as long as it can prevent the operator&#39;s fingers to reach in to ring  100 . 
         [0033]    A third stove embodiment of the present invention is shown in  FIG. 5 . The three short legs  110 ,  112  and  114  of the first embodiment of the present invention in  FIG. 3A  are connected to three long legs  170 ,  172  and  174  through couplers  180 ,  182  and  184  (not shown in  FIG. 5 ). Each short leg and long leg are plugged into the two ends of a coupler, i.e., short leg  110  going into the top end of coupler  180  while long leg  170  into the bottom end of the same coupler  180 . Finally both short and long legs are fastened by screws. For example, short leg  110  is fastened to coupler  180  by screw  190  while long leg  170  is fastened to couple  180  by screw  192 . In this way the short leg version of  FIG. 3A  and three long legs  170 ,  172  and  174  for a study long leg version. 
         [0034]    It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive. The scope of the invention will be indicated by the appended claims rather than by the foregoing description. And all changes, which come within the meaning and range of equivalency of the claims, are therefore intended to be embraced therein.