Abstract:
A gas burner assembly connected to a source of gas. The gas burner assembly has a burner body. The burner body has a generally enclosed chamber with a central axis and is configured with a generally circular wall. Ports are formed at the top of the wall and are in flow communication to an area external the burner body for combustion of the gas. A venturi directs the flow of gas from the source of gas into the chamber through an opening where the opening is offset from the central axis of the chamber. The burner body further has a stability chamber.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention relates generally to a method and apparatus for gas burners, and, more particularly, a method and apparatus for reduced circumference gas surface burner used in a gas-cooking product. 
         [0002]    Atmospheric gas burners are commonly used as surface units in household gas cooking appliances. A significant factor in the performance of gas burners is their ability to withstand airflow disturbances from the surroundings, such as room drafts, rapid movement of cabinet doors, and oven door manipulation. Manipulation of the oven door is particularly troublesome because rapid openings and closings of the oven door often produce respective under-pressure and over-pressure conditions under the cook top. 
         [0003]    These under-pressure and over-pressure conditions cause related pressure variations in the gas entering the burner chamber. Gas refers to any gas or fuel air mixture. The pressure variations can translate into flow disturbances at the burner ports causing flame extinction. 
         [0004]    Some commercially available gas burners employ dedicated expansion chambers to attempt to improve stability performance. These expansion chambers are intended to dampen flow disturbances before such disturbances reach a respective stability flame. This damping is typically attempted by utilizing a large area expansion between an expansion chamber inlet and an expansion chamber exit, typically expanding by a factor of about ten. Accordingly, the velocity of a flow disturbance entering a burner throat is intended to be reduced by a factor of about ten prior to reaching a respective stability flame, thereby reducing the likelihood of flame extinction. Large area expansion and disturbance damping are not typically present in conventional main burner ports, making conventional main burner ports susceptible to flame extinction, especially at low burner input rates. Simmer stability is generally improved as the area expansion ratio is increased. If an expansion chamber inlet is sized too small, however, the gas entering an expansion chamber may be insufficient to sustain a stable flame at the expansion chamber port. 
         [0005]      FIG. 1  illustrates an exemplary freestanding gas range  100  in which the herein described methods and apparatus may be practiced. Range  100  includes an outer body or cabinet  112  that incorporates a generally rectangular cook top  114 . An oven, not shown, is positioned below cook top  114  and has a front-opening access door  116 . A range backsplash  118  extends upward of a rear edge  120  of cook top  114  and contains various control selectors (not shown) for selecting operative features of heating elements for cook top  114  and the oven. It is contemplated that the herein described methods and apparatus is applicable, not only to cook tops which form the upper portion of a range, such as range  100 , but to other forms of cook tops as well, such as, but not limited to, built in cook tops that are mounted to a kitchen counter. Therefore, gas range  100  is provided by way of illustration rather than limitation, and accordingly there is no intention to limit application of the herein described methods and apparatus to any particular appliance or cook top, such as range  100  or cook top  114 . 
         [0006]    Cook top  114  includes four gas fueled burner assemblies  200  which are positioned in spaced apart pairs positioned adjacent each side of cook top  114 . Each pair of burner assemblies  200  is surrounded by a recessed area  124  of cook top  114 . Recessed areas  124  are positioned below an upper surface  126  of cook top  114  and serve to catch any spills from cooking utensils (not shown in  FIG. 1 ) being used with cook top  114 . Each burner assembly  200  extends upwardly through an opening in recessed areas  124 , and a grate  128  is positioned over each burner  200 . Each grate  128  includes a flat surface thereon for supporting cooking vessels and utensils over burner assemblies  200  for cooking of meal preparations placed therein. 
         [0007]    While, cook top  114  includes two pairs of grates  128  positioned over two pairs of burner assemblies  200  it is contemplated that greater or fewer numbers of grates could be employed with a greater or fewer number of burners without departing from the scope of the herein described methods and apparatus. Further, the burner assembly may rest directly on the cook top or within recesses. 
         [0008]    Gas burners are subjected to pressure fluctuations both above the cook top on which they are mounted, as well as below. These pressures fluctuations can extinguish the flames of a burner when it is turned down to a very low setting. It is well known in the art that the addition of a stability chamber can improve stability at low flame settings. However, this concept requires the venturi tube to be located substantially adjacent to the inlet of the stability chamber. In traditional practice, the venturi is located in the center of round burners to provide uniform distribution of gas. Thus, the minimum diameter of the chamber of a burner that has a centrally located venturi and adjacent stability chamber can be approximated by the equation: Diameter of chamber=Diameter of venturi+2× radial length of stability chamber. Because the stability chamber requires a finite volume and length to function properly, a designer is often left with a burner diameter larger than desired in order to fit these features. Larger diameter burners are often not desired when space constraints, part cost, or efficiency demands are considered. 
         [0009]      FIG. 2  is a side view of a known burner base. The width  164  of the burner body  150  is determined by the internal features, shown in  FIG. 3 . The height  162  provides height for the burner to be proximate to a grating (not shown) which, supports cooking vessels. The grating may be removeably attached to the burner body  150 . Burner ports  154  are at the top of a wall  168  of the burner body. The wall  168  is generally annular and is formed about a central axis. Typically located above the burner ports is a burner cap (not shown). The burner cap closes the burner body  150  to create an internal chamber  156  such that the ports  154  and the stability chamber are the only exit for the gas during operation. The gas enters the burner body  150  through a venturi  152  from a burner throat  160  and accumulates in the chamber  156  before exiting the ports  154 . 
         [0010]      FIG. 3  is a top view of a known burner base  150  that can be used in a burner assembly for a gas range. Traditionally, the venturi  152  is located along the central axis  166  of a ring of burner ports  154 . Stability chamber  160  is located to one side of the chamber  156  and opposite the stability chamber  160  is igniter mount  158  for mounting an electrode (not shown). The minimum diameter of the ring of ports is restricted by the size of the stability chamber  160  and the size of the venturi  152 , and this is because the venturi  152  is located in the center of the burner. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0011]    In one aspect, a gas burner assembly connected to a source of gas. The gas burner assembly has a burner body. The burner body has a generally enclosed chamber with a central axis and is configured with a generally circular wall. Ports are formed at the top of the wall and are in flow communication to an area external the burner body for combustion of the gas. A venturi directs the flow of gas from the source of gas into the chamber through an opening where the opening is offset from the central axis of the chamber. The burner body further has a stability chamber. 
         [0012]    In another aspect, a gas range is provided. The gas range has a cook top and a gas burner assembly positioned in the cook top. The burner assembly is connected to a source of gas. The gas burner assembly has a burner body. The burner body comprises a chamber. The chamber has a generally circular wall with a central axis. A venturi directs the flow of gas from the source of gas into the chamber through an opening where the opening is offset from the central axis of the chamber. The burner body also comprises a stability chamber. Ports are formed at the top of the wall and are in flow communication with an area external the burner body for combustion of the gas. A burner cap is positioned on the burner body. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a perspective view of a gas range according to an embodiment of the invention. 
           [0014]      FIG. 2  is a side view of a burner body for a cooking appliance known in the art. 
           [0015]      FIG. 3  is a top view of a burner body for a cooking appliance known in the art. 
           [0016]      FIG. 4  is a top view of a burner body of a burner assembly of the range of  FIG. 1  according to an embodiment of the invention. 
           [0017]      FIG. 5  is a side view of a burner body of a burner assembly of the range of  FIG. 1  according to an embodiment of the invention. 
           [0018]      FIG. 6  is a perspective view of a multi-ring burner assembly incorporating a burner body according to an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    While the methods and apparatus are herein described in the context of a gas-fired cook top, as set forth more fully below, it is contemplated that the herein described method and apparatus may find utility in other applications, including, but not limited to, gas heater devices, gas ovens, gas kilns, gas-fired meat smoker devices, and gas barbecues. In addition, the principles and teachings set forth herein may find equal applicability to combustion burners for a variety of combustible fuels. The description herein below is therefore set forth only by way of illustration rather than limitation, and is not intended to limit the practice of the herein described methods and apparatus. 
         [0020]    Typically, for a burner, flow distribution is governed by individual port areas. A larger port from a chamber exhibits higher relative flow rates than smaller ports from the same chamber. Thus, port sizing, a static attribute of a burner, primarily determines percentage of total flow exhibited by a port. A secondary consideration is the distance a particular port is from the venturi. These attributes define the distribution of flow rates across the burner ports. 
         [0021]      FIG. 1  illustrates an exemplary freestanding gas range  100  in which the herein described methods and apparatus may be practiced. Range  100  includes an outer body or cabinet  112  that incorporates a generally rectangular cook top  114 . An oven, not shown, is positioned below cook top  114  and has a front-opening access door  116 . A range backsplash  118  extends upward of a rear edge  120  of cook top  114  and contains various control selectors (not shown) for selecting operative features of heating elements for cook top  114  and the oven. It is contemplated that the herein described methods and apparatus is applicable, not only to cook tops which form the upper portion of a range, such as range  100 , but to other forms of cook tops as well, such as, but not limited to, built in cook tops that are mounted to a kitchen counter. Therefore, gas range  100  is provided by way of illustration rather than limitation, and accordingly there is no intention to limit application of the herein described methods and apparatus to any particular appliance or cook top, such as range  100  or cook top  114 . 
         [0022]    Cook top  114  includes four gas fueled burner assemblies  200  which are positioned in spaced apart pairs positioned adjacent each side of cook top  114 . Each pair of burner assemblies  200  is surrounded by a recessed area  124  of cook top  114 . Recessed areas  124  are positioned below an upper surface  126  of cook top  114  and serve to catch any spills from cooking utensils (not shown in  FIG. 1 ) being used with cook top  114 . Each burner assembly  200  extends upwardly through an opening in recessed areas  124 , and a grate  128  is positioned over each burner  200 . Each grate  128  includes a flat surface thereon for supporting cooking vessels and utensils over burner assemblies  200  for cooking of meal preparations placed therein. 
         [0023]    While, cook top  114  includes two pairs of grates  128  positioned over two pairs of burner assemblies  200  it is contemplated that greater or fewer numbers of grates could be employed with a greater or fewer number of burners without departing from the scope of the herein described methods and apparatus. Further, the burner assembly may rest directly on the cook top or within recesses. 
         [0024]    Gas burners are subjected to pressure fluctuations both above the cook top on which they are mounted, as well as below. These pressures fluctuations can extinguish the flames of a burner when it is turned down to a very low setting. It is well known in the art that the addition of a stability chamber can improve stability at low flame settings. However, this concept requires the venturi tube to be located substantially adjacent to the inlet of the stability chamber. In traditional practice, the venturi is located in the center of round burners to provide uniform distribution of gas. Thus, the minimum diameter of the chamber of a burner that has a centrally located venturi and adjacent stability chamber can be approximated by the equation: Diameter of chamber=Diameter of venturi+2× radial length of stability chamber. Because the stability chamber requires a finite volume and length to function properly, a designer is often left with a burner diameter larger than desired in order to fit these features. Larger diameter burners are often not desired when space constraints, part cost, or efficiency demands are considered. 
         [0025]      FIG. 2  is a side view of a known burner base. The width  164  of the burner body  150  is determined by the internal features, shown in  FIG. 3 . The height  162  provides height for the burner to be proximate to a grating (not shown) which, supports cooking vessels. The grating may be removeably attached to the burner body  150 . Burner ports  154  are at the top of a wall  168  of the burner body. The wall  168  is generally circular and is formed about a central axis. Above the burner ports is a burner cap (not shown). The burner cap closes the burner body  150  to create an internal chamber  156  such that the ports  154  and the stability chamber are the only exit for the gas during operation. The gas enters the burner body  150  through a venturi  152  from a burner throat  160  and accumulates in the chamber  156  before exiting the ports  154 . 
         [0026]      FIG. 3  is a top view of a known burner base  150  that can be used in a burner assembly for a gas range. Traditionally, the venturi  152  is located at the central axis  166  of a ring of burner ports  154 . Stability chamber  160  is located to one side and opposite the stability chamber  160  is igniter mount  158  for mounting an electrode (not shown). The minimum diameter of the ring of ports has been restricted by the size of the stability chamber  160  and the size of the venturi  152 , since the venturi  152  was located in the center of the burner. 
         [0027]    The trend in the burner industry has been to move towards burners having multiple port rings and multiple stages as shown in  FIG. 6 . Typically, a larger “doughnut” shaped outer burner  300  concentrically surrounds an inner smaller burner  200 . This allows a wide range of heat outputs and allows more heat to be supplied to the center of the cooking vessel rather than heating the outer perimeter of the cookware. Consequently, if the inner burner  200  is large, the outer burner  300  must be increased in size to maintain a minimum spacing between the burners for sufficient airflow between the rings. This airflow is important to provide sufficient oxygen for the combustion of the gas. Thus, if the diameter of the inner burner is minimized, the outer burner may be made smaller. The reduction of burner size improves the residence time of the burning gas under the cooking vessel and improves efficiency by maximizing heat transfer to the cooking vessel. 
         [0028]    Referring now to  FIGS. 4 ,  5  and  6 , where like reference numbers indicate same or similar features.  FIG. 4  is a top view of a burner body  200  of a burner assembly of the range  100  of  FIG. 1  according to an embodiment of the invention.  FIG. 5  is a side view of a burner body  200  of a burner assembly of the range  100  of  FIG. 1 . 
         [0029]    The venturi  204  is offset from the axis  224  and as a result, unlike the prior art burners, the diameter of the burner body  200  is not directly determined by features internal to the burner body. As a result of this improvement, the stability chamber  206  remains a useful size without a portion of stability chamber  206  being outside the annular ring of ports. The height of the burner body  200  provides height for the burner to be proximate to cooking vessel. This can be particularly important as shown in  FIG. 6  where a gas multi-ring burner assembly  300  is configured outside the gas burner assembly  200 . Further, with a multi-ring burner assembly supports  210  provide a means for centering and properly locating the burner throats  308  of outer burner  300 . 
         [0030]    Burner ports  212 ,  214 ,  216 ,  218  are at the top of a wall  222  of the burner body  200 . The wall  222  is generally annular and is formed about a central axis  224 . Above the burner ports  212 ,  214 ,  216 ,  218  is a burner cap  230 . The burner cap  230  (shown in  FIG. 6 ) closes the burner body  200  so as to create an internal chamber  222  such that the ports  212 ,  214 ,  216 ,  218  are the only exit for the gas during operation. The gas enters the burner body  200  from a burner throat  220  and accumulates in the chamber  222  before exiting the ports  212 ,  214 ,  216 ,  218 . 
         [0031]    Because the venturi  204  is offset, from axis  224  each pair of ports  212 ,  214 ,  216 ,  218  are angled and shaped differently to optimize flow patterns based on the distance to the venturi. The longitudinal axis of ports  212 ,  214 ,  216 ,  218  are not specifically in radial alignment to either the center axis  224  or the center of the venturi  204 . Each port is configured to promote flow and minimize obstruction. Ports  218 , which are proximate to the venturi  204 , can be subjected to substantial flow variations. To discourage the flow variations from affecting the burner flame ports  218  are taken out of linear alignment with venturi  204 . 
         [0032]    Referring to  FIG. 6  a multi-ring burner assembly is shown. The multi-ring burner assembly has an inner burner assembly  200  and an outer burner assembly  300 . Inner burner assembly has a single ring of ports and burner cap  230 . Outer burner assembly  300  has 2 rings of ports. One ring of ports faces to the outside, the second ring of ports (hidden by cap  306 ) faces to the inside, or toward the inner burner assembly  200 . Gas throats  308  provide a supply of gas to the outer burner body  302 , and pass through supports  210  (see  FIGS. 4 and 5 ) of the inner burner assembly  200 . 
         [0033]    The methods and apparatus described herein facilitate providing substantially higher heat outputs on gas surface burners, thereby improving an elapsed time to bring a food load to a desired temperature. By reducing the diameter of the burner heat transfer to smaller cooking vessels is improved affording improved efficiency and reduced energy requirements. 
         [0034]    While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.