10052989647* ;55 14 95 ;Patent No. 5 - Complete Specification ;A BURNER AND A FLAME TAMER FOR A GAS COOKER ;We, Sunbeam Corporation Limited, hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement. ;INTELLECTUAL PROPERTY OFFICE OF N.Z. ;2 3 NOV 2006 ;RECEIVED ;Page 1 ;005173457 ;A burner and a flame tanner for a gas cooker Field of the invention ;The present invention relates to gas cookers. More particularly, the present invention relates to burners and flame tamers for gas cookers and may have particular application to gas fired barbecues. ;Background of the invention ;Gas cookers, particularly gas cookers that are barbecue grills continue to be popular outdoor cooking devices, and are typically in the form of a cart supporting a fire box or cooking chamber. The cooking chamber is generally arranged so that it has gas burners 10 in its lower portion, and a flame tamer or lava rocks is provided above the gas burners to distribute heat by diffusion and to minimise flare ups. A cooking surface is positioned above the flame tamers or lava rocks to support food when it is being cooked. ;The gas burners used in the barbecue are typically in the form of tubes or flat channels that have a series of openings or apertures through which the gas travels when the gas 15 supply is turned on. Generally, where multiple burners are used, these burners extend from a common manifold, the manifold being connected at one end to a gas supply line. The gas supply line is connected to a gas source, such as a gas bottle or a town line. A valve with a control knob is typically provided for each burner to enable a user to regulate the flow of gas to each burner and therefore control the amount of heat from 20 each burner. A gas flow is brought to the burner assembly, where it is ignited to form a flame, which serves as the heat source for cooking the food in the cooking chamber. ;A deficiency of many barbecues is that the cooking surface is not heated to a uniform temperature by the burners, leading to some portions of the cooking surface being hotter relative to other portions of the cooking surface. This can lead to food being over-25 or under-cooked on certain locations of the cooking surface. ;005261082 ;Summary of the invention ;According to a first aspect of the invention, there is provided components for a gas cooker including: ;a burner including an elongate tubular body extending from a first end to a 5 second end for receiving therein gas from a gas supply that is connectable to the burner to supply gas at the first end and for communicating gas received at the first end to the second end of the body, the burner including a plurality of apertures disposed between the first and second ends; and ;^ a flame tamer for location over the burner, the flame tamer having a plurality of ;10 openings configured to receive heat from a gas flame from the burner and to pass heat there through, ;wherein at least one of the burner and flame tamer is configured to compensate for temperature variation along the combination of the burner and flame tamer by providing more heat towards the first end of the burner relative to the second end of the 15 burner in comparison to if the burner had uniformly spaced and sized apertures and the flame tamer had uniformly spaced and sized openings. ;The burner may be configured to compensate for said temperature variations by differences in the size and/or distribution of the apertures between the first end and the second end that would result in more gas being delivered at the first end of the burner ^20 relative to the second end of the burner if there was constant gas pressure profile within the body between the first and second ends. ;The apertures may be of uniform size and shape and decrease in number per unit length of the body from the first end to the second end. ;The flame tamer may be configured to compensate for said temperature variation 25 by the openings being distributed and/or shaped to redistribute the heat received by the flame tamer from its respective burner. ;The elongate tubular body may be a cylindrical body and the apertures may be circular. ;INTELLECTUAL PROPERTY OFFICE OF N.Z. ;-7 JUN 2007 RECEIVED ;005261082 ;INTELLECTUAL PS0PI=HIY OFFICE OF N.Z. ;-7 JUN 2007 RECEIVED ;The burner may include two rows of said apertures located on opposite sides of the body and one or more cross-lighting apertures in the body that are located between the rows of apertures and closer to the first end of the burner than to the second end. ;According to a second aspect of the invention, there is provided components for 5 a gas cooker including: ;a burner including a body that is connectable to a gas supply to enable receipt by the body of gas from the gas supply at a first end of the body, d is suitable for communicating gas received at the first end to a second end of the body, and includes ^ a plurality of apertures between the first and second ends for delivering gas to be ignited 10 to provide heat for cooking, wherein the apertures are configured to deliver more gas at the first end of the burner relative to the second end of the burner if there was constant gas pressure between the first and second ends; and a flame tamer locatable over the burner, the flame tamer having a plurality of openings configured so that when the flame tamer is located over the burner, the flame 15 tamer receives heat from the burner and passes more heat at or near the first end of the burner relative to the heat that passes the flame tamer towards second end of the burner. ;The components for a gas cooker may include a plurality of the burners and one or more said flame tamers. ;m w 20 The elongate body of the burner may be linear and the second end of the body may be closed. ;A gas cooker of the present invention may include the components described in the immediately preceding paragraphs. ;According to a third aspect of the invention, there is provided a burner for a gas 25 cooker, the burner including an elongate body including a first end connectable to a gas supply and a second end, wherein the body is adapted to communicate gas received at the first end of the body to the second end and includes a plurality of apertures located between the first and second ends, wherein the burner includes means to compensate for variation in heat output along the burner due to variations in gas pressure along the 30 length of the body of the burner and/or variations in the flow of gas out of the apertures along the length of the body of the burner, wherein the means to compensate is ;005261082 ;provided at least in part by the burner being configured to deliver more gas towards the first end of the burner relative to the second end of the burner if there was a constant gas pressure profile within the body between the first and second ends.. ;The means to compensate may be provided at least in part by apertures having a 5 combined area per unit length of the body which varies along the length of the body. The apertures may be larger and/or provided in higher number per unit length of the body towards the first end of the body relative to the second end of the body. The apertures may be circular. ;According to a fourth aspect of the present invention, there is provided a burner So for a gas cooker, the burner including an elongate body including a first end connectable to a gas supply and a second end, wherein the body is adapted to communicate gas received at the first end of the body to the second end and includes a plurality of apertures distributed between the first and second ends, wherein the apertures are configured to achieve a more uniform heat distribution along the body of the burner by 15 providing more heat output towards the first end of the burner relative to the second end of the burner in comparison to if the apertures were the same size and provided with constant density per unit length between the first and second ends. ;According to a fifth aspect of the present invention, there is provided a burner for a gas cooker, the burner including an elongate body including a first end connectable to |20 a gas supply and a second end, wherein the body is adapted to communicate gas received at the first end of the body to the second end and includes a plurality of apertures distributed between the first and second ends, the apertures configured so as to have a decreasing density per unit length from the first end towards the second end and/or the apertures located towards the first end have an increased size relative to the 25 apertures located towards the second end. ;The elongate body of the burner may be linear and the second end of the body may be closed. ;The plurality of apertures may be located on opposite sides of the elongate body and the burner further includes one or more cross-lighting apertures located at or near 30 the first end of the body. ;INTELLECTUAL PROPERTY OFFICE OF N.2. ;-7 JUN 2007 RECEIVED ;005261082 ;6 ;The plurality of apertures may be circular and all have a diameter of approximately 2.7 mm. ;The plurality of apertures may have a distribution per unit length that increases constantly between the first and second ends of the body. ;5 According to a sixth aspect of the present invention, there is provided a flame tamer for a gas cooker having at least one elongate burner, the flame tamer including a plurality of openings extending along an axis of the flame tamer that extends between a first end and a second end of the flame tamer, wherein the flame tamer is locatable above an elongate gas burner so that the axis is parallel to the gas burner and is 110 configured so as to pass or direct more heat towards the first end relative to the second end. ;The openings of the flame tamer may be provided with larger openings towards the first end relative to the second end; and/or provided in a relatively higher number per unit length at the first end relative to the second end. ;15 At least some of the openings may include a louvre that tends to direct more heat towards one end of the flame tamer. At least some of the openings may include another louvre that overall does not direct heat towards one end of the flame tamer. The flame tamer may include a plurality of openings with louvres that tend to direct more heat towards the first end of the flame tamer and a plurality of openings with louvres that >20 overall do not direct heat towards either end of the flame tamer, wherein the plurality of openings with louvres that tend to direct more heat towards the first end of the flame tamer are all located towards the first end of the flame tamer relative to the openings with louvres that overall do not direct heat towards either end of the flame tamer. The openings with louvres that tend to direct more heat towards the first end of the flame 25 tamer have a single opening and the openings with louvres that overall do not direct heat towards either end of the flame tamer have two openings of approximately equal area, which is approximately half the area of said single opening. ;Every opening of the flame tamer may have an associated louvre. ;The flame tamer may include two rows of openings extending along parallel axes 30 of the flame tamer between the first end and the second end. The flame tamer may include a vertex extending parallel to said axes between the axes. The flame tamer may ;INTELLECTUAL PROPERTY OFFICE OF N.Z. ;-7 JUN 2007 ;005261082 ;include downwardly depending flanges that extend between the first and second ends of the flame tamer and which define sides of the flame tamer. ;According to a seventh aspect of the invention, there is provided a gas cooker having a cooking chamber with a front and rear wall, two side walls extending 5 between the front and rear walls, a base, and at least one burner as described in the preceding paragraphs, wherein the first end of the burner is located proximate to the front wall of the cooking chamber and the second end of the burner is located proximate to the rear wall of the cooking chamber. ;The gas cooker may further include a lid connected to the rear wall, the lid when 10 closed forming in cooperation with the front wall, rear wall, side walls and base a substantially closed cooking chamber. ;According to a ninth aspect of the invention, there is provided a gas barbecue including: ;a cooking chamber with a front and a rear wall, two side walls extending between 15 the front and rear walls, and a base; ;a connector for connection to a gas supply and a manifold to receive gas from the connector, the manifold having a plurality of outlets located at the front wall of the cooking chamber; ;a plurality of elongate burners, each burner being connected to one of the outlets 20 of the manifold at a first end and extending across the cooking chamber from the front wall towards the rear wall to terminate at a second end, each burner having a plurality of apertures along its length that have decreasing area with increasing distance from the first end and/or that have a lesser number per unit length towards the second end relative to the first end. ;25 The gas barbecue may further include an elongate flame tamer located or locatable above and in line with a said burner so that a first end of the flame tamer is located over the first end of the burner and a second end of the flame tamer is located over the second end of the burner, the flame tamer having a plurality of openings along its length, the openings having decreasing area with increasing distance from the first 30 end of the flame tamer and/or a relatively higher number of openings per unit length in the direction of the first end of the flame tamer relative to the second end. ;INTELLECTUAL PROPERTY OFFICE OF N.Z. ;-7 JUN 2007 ;DCrrii/rn ;005173457 ;8 ;second end of the burner, the flame tamer having a plurality of openings along its length, the openings having decreasing area with increasing distance from the first end of the flame tamer and/or a relatively higher number of openings per unit length in the direction of the first end of the flame tamer relative to the second end. ;Further aspects of the present invention, which should be considered in all its novel aspects, will become apparent from the following description, given by way of example only and with reference to the accompanying drawings. ;Brief description of the drawings ;Figure 1 shows a cut-away view of a portable barbecue which includes a burner and 10 flame tamer according to a first embodiment of the present invention. ;Figures 2a-c show perspective views of flame tamers according to various embodiments of the present invention. ;Figures 3a-c show perspective views of burners according to various embodiments of the present invention. ;15 Detailed description of the embodiments ;^ In the accompanying drawings like components are identified by the same reference numerals. ;Although the present description is directed towards the most preferred application and embodiment of the present invention as presently contemplated of a barbecue grill, it 20 will be appreciated that the burner and the flame tamer of the present invention may also have application to other gas cookers. ;Referring to Figure 1, a barbecue grill 10 includes a cooking chamber or firebox 12. The enclosure of the firebox 12 is formed by a front wall 13, a rear wall 14 and two side walls 15, 16 (not shown) mounted to a base 17. Optionally, the base 17 of the firebox may be 25 shaped to include peripheral walls which are inclined downwardly to form a drip tray 18 which directs grease and cooking remnants to a removable drip pan 20. The firebox ;005173457 ;9 ;depicted is exemplary and other fireboxes are suitable for use with the present invention. The firebox 12 may be made from aluminium or steel and may be mounted on a cart (not shown). ;The grill 10 also includes a generally elongate burner 22, which extends from a first end 5 74 through an aperture 13a in the front wall 13 of the firebox 12. The burner 22 is affixed at its second end 76 to the rear wall 14 of the firebox, through the use of a suitable fixing means such as rivets, screws, or the like. A single grill 10 may have between two and eight burners 22 extending from the front wall 13 to the rear wall 14 of ^ the firebox in parallel, although some smaller grills may have a single burner and some TO larger grills may have more than eight burners. ;Fuel is supplied to the burners of the firebox through a manifold 28. The manifold 28 may include a plurality of outlets, one for each burner 22 of the grill 10 and the manifold is in turn connected to an external fuel tank or gas supply line (not shown). ;The gas that is supplied to the burner 22 is emitted through apertures 30 located about 15 the generally elongate burner 22. The apertures 30 in the burner 22 allow the gas to pass there through and may be aligned linearly along the burner length to discharge the gas. As is known in the art, the gas fuel flowing through the apertures 30 in the burner 22 is ignited and the resulting flame produces heat for cooking. The burner 22 is capped ^ or otherwise sealed at the second end 76 so as to ensure that a sufficient quantity and 20 pressure of gas is emitted from the openings 30. ;Control knobs 32, 34 are provided on a fascia and control flow regulators (not shown) regulate the flow through each burner. An ignition switch 38 may also be provided to activate an ignition means 40 in an arrangement well known in the art. The ignition means 40 may be arranged to ignite one or more apertures of the burner 22 near to the 25 first end 74. Once ignited, the flame spreads to the other apertures 30 of the burner 22 and to any adjacent burner(s) 22. ;The grill 10 further includes a generally elongate flame tamer 50, which may be supported by lips 51, 54 formed in the front and rear walls 13, 14 respectively, so as to ;005173457 ;10 ;be located above the burner 22. The flame tamer 50 includes a plurality of openings 52 along its longitudinal axis for facilitating the passage of heat from the burner 22 to a cooking plate 57 supported on the top of the firebox 12. ;Referring to Figures 2a-c, the three embodiments of flame tamers 50a-c are generally 5 shown. The flame tamers 50a-c are each elongate, to match the elongate shape of the burners 22. The flame tamers 50a-c may be formed in the generally V shaped form depicted to assist in deflecting grease and other remnants from cooking operations away from the burner. The flame tamers 50a-c include a downwardly depending lip 56 ^ along each side. The flame tamers 50a-c are therefore shaped to readily allow fluids to TO drain off the flame tamers 50 into the drip tray 18 of a firebox 12 in which they are installed, guiding the fluids so as to generally avoid the burners 22 located below the flame tamers 50. The flame tamers 50a-c are formed from stainless steel or other suitable materials. The flame tamers 50a-c include a plurality of openings, which are generally aligned and are aligned parallel to the longitudinal axis of the respective flame 15 tamer 50a-c between a first end 58 and a second end 60. ;Turning to Figure 2a, the flame tamer 50a shown also includes first louvres 62 towards the first end 58 of the flame tamer 50a from about the longitudinal mid-point of the flame tamer 50a. The louvres 62 each define a single opening 52 and are shaped to direct more heat in the direction of the front wall of the firebox 12 than if the openings 52 were TO provided without the louvres 62. Towards the second end 60 of the flame tamer 50a, second louvres 63 are provided that each define a pair of openings 53, that are overall not arranged to direct heat towards the front or rear of the flame tamer 50a. Heated air can flow out of the openings around either side of the louvres 63, but only out of one side of the louvres 62. Therefore, due to the asymmetry of the flame tamer 50a, the 25 arrangement of louvres 62 near to the openings 52 assists in the flame tamer 50a directing relatively more heat towards the first end 58 of the flame tamer 50a relative to the second end 60. As shown in Figure 2a, the louvres 62 may define a larger single opening 52, whereas the louvres 63 define two smaller openings 53. In one embodiment the opening 52 may have approximately double the area of each of the 30 openings 53. ;005173457 ;11 ;Turning to Figure 2b, the flame tamer 50b has louvres 63 like those provided in the flame tamer 50a, which are distributed to define openings 53 that are spaced apart at increased intervals with increasing distance from the first end 58b. The differential spacing means that there are a relatively higher number of openings per unit length provided at the first end 58b relative to the second end 60b. ;Turning to Figure 2c, the flame tamer 50c has louvres varying in size from large 63a to small 63b to define pairs of openings 53a and 53b respectively that are closer together towards the first end 58c relative to the second end 60c. The space between the louvres is constant along the length of the flame tamer 50c. Accordingly, as there is a higher TO density of openings per unit length towards the first end 58c, then more heat passes the flame tamer 50c at this end. ;In addition to or as an alternative providing a higher density of openings 52 per unit length towards one end of the flame tamer 50, the size of the openings could be varied to provide larger openings at the end where an increased amount of heat passage is 15 required relative to if the openings were uniform in size. ;Referring to Figures 3a to 3c three exemplary burners 22a-c are shown. The burners 22a-c each include a generally elongate body 72, having a first end 74 and a second end 76. The burners 22a-c are connectable to a gas supply (not shown) using a standard connector 78, which is located at the first end 74. The body 72 is arranged to 20 communicate the gas from the first end 74 to the second end 76 of the body 72. A plurality of apertures 30 of varying size or distribution per unit length are located along both sides of the body 72 (one side only visible in Figures 3a to 3c). The apertures 30 are configured to deliver more gas at the first end 74 of the burner 22 relative to the second end 76 of the burner if there was a constant gas pressure within the body 72. ;25 One or more cross-lighting apertures 80 may be provided to ignite the other side of the burner 22 once one side has been ignited. The cross-lighting aperture (s) 80 may be located towards the first end 74 of the burner 22 to assist in providing more heat output at the first end and to alter the pressure profile from front to back. ;005173457 ;12 ;Turning to Figure 3a, the apertures 30 include apertures ranging from a large aperture 79, located at the first end 74 to a small aperture 81 located at the second end 76. The apertures 30 are shown as circular in each of the embodiments in Figures 3a-c, but this is not essential and other shapes of aperture may be utilised. The arrangement of the 5 apertures 30 of the burner 22a allows for increased gas flow at the first end 74 where the gas pressure is constant in the gas body 72, than if the apertures 77 were all the same size. ;Referring to Figure 3b, the apertures 33 of the burner 22b are all the same shape and ^ size, but are spaced closer together towards the first end 74b of the burner 22b. This TO means that the apertures of the burner are configured to deliver more gas at the first end of the burner relative to the second end of the burner if there was constant gas pressure in the body, or to compensate for variations in gas pressure and/or flow in particular with regards to a closed end burner so that a relatively constant flow of gas along the length of the burner is achieved. Accordingly, in one embodiment, any 15 variation in combined area per unit length of apertures, by number and/or size thereof, can be used to vary the gas delivery or to compensate for variations in gas pressure and/or flow, in particular with regard to a closed end burner so that a relatively constant flow of gas along the length of the burner is achieved. ;The diameter of the apertures in the embodiment shown is 2.7mm. The spacing between the first two holes at the first end of the burner 74b is 5.0mm, with an increase in the spacing of 0.1mm per hole. The spacing at the second end 76b is therefore maximal, at 8.5mm. It would be appreciated that these spacings are exemplary only, and alternate aperture diameters and spacing may be selected. ;Alternative methods of creating this difference in gas delivery between the ends of the 25 burner may be used. For example, it may be possible to use internal baffles that restrict the flow out of the apertures at the second end relative to the first end. ;Turning to Figure 3c, the apertures 33 of the burner 22c at the first end 74c are arranged in three rows towards the first end 74c, in two rows in a mid porion, and in a single row towards the second end 76c. This results in an increased number of ;apertures per unit length of the burner at the first end 74c relative to the second end 76c. It would be appreciated that this arrangement is exemplary only, and alternative arrangements of the apertures (including with different numbers of rows) are possible. ;It would be appreciated that any one of the burners 22 of the present invention may be used with any one of the flame tamers 50 of the present invention. It would be appreciated that other embodiments of the flame tamer and burner according to the present invention may also be combined. Furthermore, it would be appreciated that a burner according to an aspect of the present invention may be used with a standard barbecue or cooker having a standard flame tamer or a barbecue or cooker without a flame tamer. Also, it would be appreciated that it would be possible to use the flame tamer according to a further aspect of the present invention with a standard burner. ;It will be understood that the invention disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention. ;It will also be understood that the term "comprises" (or its grammatical variants) as used in this specification is equivalent to the term "includes" and should not be taken as excluding the presence of other elements or features. ;005261082v1.doc ;1. ;5 ;15 ;2. ;20 ;3. ;25 4. ;5. ;30 *