Patent Publication Number: US-2002011244-A1

Title: Tented gas burner for grill

Description:
FIELD OF THE INVENTION  
       [0001] The present invention relates to gas barbecue grills generally and more particularly to burners and tented burners for grills.  
       BACKGROUND INFORMATION  
       [0002] In general, it is known to use tented burners in barbecue grills. However, presently available barbecue grills have several disadvantages. For example, known tented burner arrangements are ineffective in providing an optimum and even distribution of heat to the cooking surface of the grill. In addition, presently available grills do not effectively control flare-ups, as are commonly caused by drippings onto the burner or the tent arranged above the burner.  
       SUMMARY OF THE INVENTION  
       [0003] The present invention provides a grill having a tent structure mounted over a gas burner. The tent structure is configured in such a way as to allow the periphery of the cooking surface to achieve a higher temperature than that allowed by conventional tented burner arrangements, thereby providing an even distribution of heat to the cooking surface of the grill.  
       [0004] The present invention also provides a grill having a tent or combination of tents to provide improved flare-up control.  
       [0005] In addition, the present invention provides a gas grill having a stamped sheet metal burner assembly with top-side, multi-level porting to enhance even distribution of heat across the cooking surface. This results in a low-volume, efficient burner having a longer operating lifespan. Moreover, the use of sheet metal components provides substantial cost and assembly benefits. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0006]FIG. 1 is an exploded perspective view of an exemplary embodiment of a grill in accordance with the present invention.  
     [0007]FIG. 2 is an exploded perspective view of the burner assembly of FIG. 1.  
     [0008]FIG. 3A shows an exploded perspective view of a venturi sub-assembly in accordance with the present invention. FIGS. 3B and 3C are bottom and side views, respectively, of a portion of the venturi sub-assembly.  
     [0009]FIG. 4 is a cross-sectional view of the gas grill of FIG. 1.  
     [0010]FIG. 5 is a cross-sectional view of a further embodiment of a gas grill of the present invention.  
    
    
     DETAILED DESCRIPTION  
     [0011] The present invention is directed to a burner arrangement for a gas grill. As shown in FIGS.  1 - 3  an exemplary embodiment of the gas grill comprises a bi-level tent configuration, a burner assembly  1 , and a main grill shell  2 .  
     [0012] A lower, first tent  3  is generally configured in the shape of the letter “I”. A main, central portion of the first tent  3  comprises a first sloped surface  4  and a second sloped surface  5  which meet along a ridge  6 . In the exemplary embodiment shown, the sloped surfaces  4  and  5  are arranged with an angle of approximately 120 degrees therebetween. On each end of the main portion of the first tent  3  is a transverse tent-like structure  7   a, b.  Each transverse tent segment  7   a, b  comprises an outer sloped surface  8   a, b  and a medial sloped surface  9   a, b  which meet along a ridge  10   a, b.  The ridges  10   a, b  are substantially perpendicular to the central ridge  6 . A mounting tab  11   a, b  for mounting the tent  3  to the grill shell  2  is arranged at a lower end of each sloped surface  8   a, b.  Each mounting tab  11   a, b  may comprise a hole for receiving a fastener therethrough. Proximate to the ends of the medial sloped surfaces  9   a, b,  openings  12   a, b, c, d  are provide for securing an upper tent structure  15 , described below.  
     [0013] The first tent  3  maximizes heat distribution, especially to the corners and to the periphery of the cooking surface. The tent  3  also prevents grease or other food drippings from contacting the burner  1 , thus protecting the burner  1  and effectively eliminating or controlling flare-ups. By thus protecting the burner  1 , it becomes possible to provide flame ports on the top side of the burner  1 , which substantially improves the longevity of the burner.  
     [0014] An upper, second tent  15  comprises a first sloped surface  16  and a second sloped surface  17  on opposite sides of a ridge  18 . The second tent preferably comprises a plurality of openings  19  arranged through the first and second sloped surfaces  16  and  17 . The openings  19  provide improved heat distribution and allow for controlled flare-ups.  
     [0015] The second tent  15  is arranged over the center section of the lower tent  3  with an air gap therebetween. In the exemplary embodiment shown, the sloped surfaces  16  and  17  are arranged with an angle of approximately 130 degrees therebetween and the tents  3  and  15  are spaced apart at their ridges (e.g., 0.02″ to 0.50″). The air gap between the tents  3  and  15  cools the tents, particularly the upper tent  15 , which helps control flare-ups. The gap between the tents also prevents drippings and food particulates from becoming trapped between the tents. The arrangement of the second tent  15  over the tent  3  also promotes an even distribution of heat to the cooking surface and allows grease to drain from the cooking surface, thereby reducing flare-ups.  
     [0016] At its corners, the second tent  15  preferably comprises tab extensions  20   a, b, c, d.  When the tent  15  is placed on the lower tent  3 , the tab extensions  20   a, b, c, d  sit in the openings  12   a, b, c, d  on the first tent  3 . The tent  15  is readily removable from the lower tent  3  such as for cleaning.  
     [0017] The burner assembly  1  will now be described. As shown in FIG. 1, the burner assembly  1  comprises a burner sub-assembly  40  and a venturi sub-assembly  25 , each of which is comprised of stamped sheet metal components. As shown in FIG. 2, the burner  1  is assembled by capturing the venturi sub-assembly  25  between upper and lower halves of the burner sub-assembly  40 . The lower half of the burner sub-assembly  40  is comprised of a stamped piece of sheet metal  21 . The upper half of the burner sub-assembly  40  is comprised of a complementary piece of stamped sheet metal  22 . The two halves are preferably joined by staking or hemming the two pieces together.  
     [0018] The upper piece of sheet metal  22  comprises raised or embossed features  26   a  and  26   b,  whereas the lower piece  21  comprises corresponding embossed features  27   a  and  27   b.  Each feature  26   a, b  and  27   a, b  is formed as a channel arranged in an elongated oval loop. The peripheries of the features  26   a  and  26   b  substantially correspond to the peripheries of the features  27   a  and  27   b,  respectively. When the two pieces  21  and  22  are joined, the features  26   a, b  and  27   a, b  form two hollow burner halves  41   a  and  41   b,  as shown in FIG. 1.  
     [0019] As shown in FIG. 2, the features  26   a, b  of the upper burner portion  22  comprise a plurality of holes or ports  24 . The ports  24  preferably are arranged in a plurality of rows on each of the features  26   a, b.  In one embodiment, a first row of ports  24  is located on side walls of each feature  26   a, b  and a second row of ports  24  is located above the first row, near the junction of the side walls and a substantially flat top surface of the feature  26   a, b.  The ports  24  arranged in the second row are preferably smaller than the ports in the first row. Such multi-level porting improves the efficiency of the burner and provides better heat distribution at the cooking surface of the grill. Furthermore, locating the ports  24  on the top side of the burner also improves burner performance and efficiency and substantially improves the longevity of the burner, as compared to conventional burners which are ported on their undersides.  
     [0020] The gas burner sub-assembly  40  also may comprise elongated slot-like openings  30  through the two pieces of stamped metal  21 ,  22 . The elongated slot-like openings  30  provide additional secondary air to enhance the performance of the gas burner assembly  1 , in particular improving the burning which occurs through the ports  24  located on or near the essentially horizontal top surfaces of the features  26   a, b  of the burner sub-assembly  40 .  
     [0021] In the exemplary embodiment shown in FIG. 2, the lower and upper pieces  21  and  22  of the burner sub-assembly  40  comprise tabs  28   a, b  and  29   a, b,  respectively, at opposite ends. When the pieces  21  and  22  are joined, the tabs  28  and  29  are joined and may be used to mount the burner  1  to the grill shell  2 . As shown in FIG. 1, the grill shell  2  may comprise openings  33  for receiving the tabs  28  and  29 .  
     [0022] The gas burner assembly  1  also comprises a venturi sub-assembly  25 . As shown in FIG. 3, the venturi sub-assembly  25  preferably comprises two pieces of stamped metal  25   t  and  26   b  which are joined, such as by hemming or staking, to form two fuel-air passages, one for each burner half  41   a, b.  Each passage provides a conduit for providing an air-fuel mixture to each burner half.  
     [0023] As shown in FIG. 3A and enlarged in FIGS. 3B and 3C, the venturi sub-assembly  25  preferably also comprises louvers  251  proximate to the inlets of the fuel-air passages. The louvers  251  comprise openings which allow primary air to be drawn into the passages. The primary air is mixed with fuel applied to the passage inlets and the fuel-air mixture is conducted to the burner halves where it is combusted. The use of primary air helps make it possible to reduce the volume of the burner. The louvers  251  are preferably arranged on the lower portion  25   b  of the venturi sub-assembly so as to shelter them from the elements (e.g., wind, rain). Moreover, the louver openings preferably should be sufficiently small so as to prevent insects from entering the passages and nesting in the burner assembly  1 .  
     [0024] When the burner assembly  1  is assembled, the venturi sub-assembly  25  is captured between the two pieces  21  and  22  of the burner sub-assembly. The venturi passages align with the burner halves  41   a, b  thus formed. An opening  37  in the venturi sub-assembly aligns with openings  36  in the pieces  21  and  22  so as to provide an opening in the completed burner assembly  1  for receiving one or more ignitors, as described below.  
     [0025] The stamped metal configuration of the burner assembly  1  allows for reduced manufacturing costs and ease of assembly compared to tubular steel.  
     [0026] As shown in FIGS. 4 and 6, the burner assembly  1  may also comprise an ignitor sub-assembly which preferably is located in the middle of the burner assembly  1 . The ignitor sub-assembly may comprise a pair of ignitors  34  placed through an opening  36  located between the burner halves  41   a  and  41   b.  For ignition, an arc is developed between the electrodes of the ignitors  34 . As shown in FIG. 6, the electrodes of the ignitors  34  are offset, thereby increasing the spacing between the electrodes. The increased spacing results in the generation of longer arcs which improves ignition. Moreover, a collector box  50  is arranged over the electrodes to improve the distribution of gas to the electrodes and to act as a windscreen. As shown in FIG. 4, the box  50  has an open back side which allows gas from the burner halves  41   a  and  41   b  to enter the box where it is trapped and ignited by the electrodes  34 . To further improve the ignition operation, there may be an increased density of ports  24  on the burner halves  41   a, b  proximate to the collector box  50 . The use of the collector box  50  and the dual ignitors  34  allows consistent, reliable and fast ignition.  
     [0027] Although a dual-burner embodiment has thus far been described, other configurations, such as a single-burner or a three-burner configuration are possible within the scope of the present invention.  
     [0028] The grill shell  2  is generally rectangular comprising two sets of opposing walls and a floor. A front wall  30   a  comprises one or more openings  31  through which the venturi sub-assembly  25  may pass. A bottom surface of the shell  2  comprises two rectangular openings  35  which allow secondary air to flow up through the bottom of the shell over the burner  1 . The shell  2  may also comprise features for suspending one or more grease catches (not shown) below the openings  35 . In the dual-burner embodiment shown it is preferable to provide two smaller catches as opposed to one larger catch so as to provide better grease collection and air flow through the openings  35 . The improved air flow helps cool the shell, thereby reducing flare-ups caused by grease trapped in the shell, and improves the provision of secondary air to the burner  1 .  
     [0029] The grill shell  2  may comprise a tent pedestal  32  on each end. Each mounting tab  11   a, b  on the first tent  3  rests on, or alternatively, is attached to a tent pedestal  32 , positioning the first tent  3  above the gas burner assembly  1 , as shown in FIG. 4.  
     [0030]FIG. 5 shows a further embodiment of a grill in accordance with the present invention. In the embodiment of FIG. 5, the tent  3  comprises a horizontal plate  13  arranged at the base of the tent between the sloped surfaces  4  and  5 . The plate  13  helps spread the heat generated by the burner, keeping the tent  3  cooler. Additionally, refractory elements, which absorb and re-radiate heat such as ceramic “hot blocks,” may be placed between the tent  3  and the plate  13  on the top side of the plate  13 , to assist in the distribution of heat.  
     [0031] While several preferred embodiments of a tented gas burner for a grill have been described herein, it is to be understood that variations may be made in the tented gas burner assembly without departing from the spirit and scope of the invention as defined by the appended claims.