In the following discussion, numerous specific details are set forth to provide a thorough understanding of the present invention. However, those skilled in the art will appreciate that the present invention may be practiced without such specific details. In other instances, well-known elements, processes or techniques have been briefly mentioned and not elaborated on in order not to obscure the present invention in unnecessary detail and description. Moreover, specific details and the like may have been omitted inasmuch as such details are not deemed necessary to obtain a complete understanding of the invention, and are considered to be within the understanding of persons having ordinary skill in the relevant art.
FIG. 1 illustrates a perspective top view of a radiant panel burner. The radiant panel burner 110 comprises a mixer 115, a plenum chamber 130 (i.e., chamber 130), a perforated ceramic grid 135 with ports 136, and a radiant panel 140. While in a preferred embodiment the grid 135 is made of a perforated ceramic material such as ceramic foam, hard ceramic (cordierite), or ceramic fiber plaque, it could also be made from a perforated metal foam, metal wire mesh or other comparable perforated material that can support surface combustion with a high level of radiant heat. The mixer 115 is a tubular intake element that connects to, and terminates on the interior of, the plenum chamber 130 (see FIG. 2), and is capable of delivering a gas & air mixture into the chamber 130. In a preferred embodiment, the plenum chamber 130 is a rectangular container that stores said gas/air mixture. Above the chamber 130 sits a perforated ceramic grid 135, which is the primary emitter of heat in the system. Ports 136 are evenly distributed throughout the grid 135, and permit the aforementioned gas/air mixture to flow from the plenum chamber 130 and be ignited on the grid's surface. Lying between 1 to 1.5 inches above the ceramic grid 135, the radiant panel 140 is an angled plate that serves as a secondary emitter of heat. Thus, there is an air gap between the radiant panel 140 (secondary heat emitter) and the ceramic grid 135 (primary heat emitter) in which the ignition and combustion of the gas occurs.
The radiant panel 140 is preferably composed of a durable metal such as steel or ceramic that can withstand high temperatures without distortion or corrosion. Its length portions are open below the panel, while its width portions possess supporting extensions 141 that extend perpendicularly outward from the sides of the panel 140, making contact with two of four perimeter extensions 139. Said supporting extensions 139 extend perpendicularly outward from the vertical sides of the plenum chamber 130 and support the weight of the radiant panel 140. In a heating capacity, the radiant panel 140 evenly distributes combustive gases, acts as a radiant emitter to provide high quality radiant heat to the cooking surface, distributes convective heat, and returns a portion of heat energy back to the ceramic emitter for fast heat-up and efficiency. Additionally, the radiant panel 140 protects the ports 136 of the grid 135 from cooking matter that inevitably falls from a cooking surface above (e.g. grill surface). The resulting burner system provides a very controlled, high temperature, high efficiency heat propagation that is also very durable under intense cooking conditions.
Burner operation begins with natural or propane gas passing through a mixer, where it is combined with 100% of the air required for combustion. An internal baffle (see baffle 231 of FIG. 2) inside the plenum chamber 130 distributes the gas/air mixture evenly under the perforated ceramic grid 135. The gas/air mixture passes through the ports 136 in the ceramic grid 135 and is ignited on the surface. This surface combustion heats the surface of the ceramic to temperatures between 1,600 and 1,800 degrees Fahrenheit. The infrared or radiant heat created by the high temperature of the ceramic is projected to the radiant panel 140. A portion of the radiant heat is reflected back to the surface of the grid 135, adding additional heat to the ceramics. The radiant panel can heat up to temperatures between 900 and 1,200 degrees Fahrenheit using conventional gases (e.g. propane), radiating a significant amount of heat to the cooking surface. The radiant panel 140 also functions to distribute convective heat from the combustive gases to the cooking surface. The air beneath the radiant panel 140 is heated and forced upward around the radiant panel 140 to provide convective heating (as described further in connection with FIG. 3). In addition to the radiating and distributing of heat, the radiant panel 140 also protects the perforated ceramic grid 135 from grease, liquids and solid debris from the grilling surface above. When used in a barbecue or gas grille, multiple burners can further provide a uniform heat distribution pattern at the cooking surface. Additional advantages include reduced flare-ups, ease of maintenance, rapid heat-up, and wind resistance.
FIG. 2 illustrates a cross-sectional side view through the center of the radiant panel burner. The depicted cross-section is made through dashed line “A” of FIG. 1, which passes through length of the radiant panel burner 210. The radiant panel burner 210 comprises a mixer 215, a plenum chamber 230 with interior baffle 231, a perforated ceramic grid 235 with ports 236, and a radiant panel 240. The mixer 215 further comprises a bracket 216 with an orifice adapter 217. The bracket 216 holds the orifice adapter 217 off from the venture and is where the air is mixed with the combustible gas. The orifice adapter 217 permits attachment to a gas source (i.e., natural or propane gas) such as by being threaded into a valve or gas manifold. A controlled quantity of said gas is channeled through to an orifice 218 found on the interior terminal end of the orifice adapter 217. The orifice 218 permits an appropriate quantity of gas to enter through to the mixer 215 via the bracket 216, thus mixing with all of the air necessary for combustion. As shown in FIG. 2, the mixer 215 initially enters into the plenum chamber 230, then extends further to penetrate the interior of baffle 231. Here, the flow of the gas/air mixture is controlled and distributed evenly under the perforated ceramic grid 235. Ports 236 permit the flow of said mixture through the grid 235 and onto its surface, where combustion can occur. From here, radiant heat is not only output to the radiant panel 240 and grilling surface above, but simultaneously conserved and exchanged with the ceramic grid 235 below. Additional convective heat is extended to the grilling surface via the radiant panel 240. The substantial level of control over gas/air flow throughout the radiant panel burner 210 allows for much more conservative gas usage. Moreover, the multi-step intake, mixture, and dissemination process ensures highly efficient energy output.
FIG. 3 illustrates a cross-sectional front view through the center of the radiant panel burner and a method for controlled heat emission and transfer. The depicted cross-section is made through dashed line “B” of FIG. 1, which passes through the width of the radiant panel burner 310. The radiant panel burner 310 comprises a mixer 315, a plenum chamber 330 with interior baffle 331, a perforated ceramic grid 335 with ports 336, and a radiant panel 340. The gas/air mixture fed into the plenum chamber 330 and interior baffle 331 via the mixer 315 is evenly distributed and fed through ports 336, reaching the surface of the ceramic grid 335 where ignition occurs. Wavy line 300 indicates said ignition, or surface combustion. From this combustion, substantial levels of radiant heat are propagated upward toward the bottom surface of the radiant panel 340, causing high levels of radiant heat to be propagated above and beyond the top exterior surface of the panel 340. Upward motion arrows 301 indicate this rising radiant heat.
Meanwhile, a portion of the radiant heat propagated within the space between ceramic grid 335 and panel 340 is returned to the grid 335, for additional heating of the ceramic element. Downward motion arrows 302 indicate this quantity of returned radiant heat, which is directed at and absorbed by the ceramic grid 335. As such, this radiant heat energy 302 is not wasted, but rather, transferred to the ceramic grid 335, which in turn becomes further heated. This provides conservation of heat 302 provides added efficiency not found in conventional burners. Accompanying these quantities of radiant heat is a portion of convective heat pushed through the open length portions of the radiant panel 340 and upward to a grilling surface. Curved motion arrows 303 indicate convectively propagated heat flowing upward and outward out from beneath the radiant panel 340. As shown, radiant panel 340 is not flat or planar, but rather, slightly angled and slopes downward from its center toward its terminal lengthwise edges. Its top surface is thus slightly raised along a line parallel to the length axis of the burner 310. The angled sections of the radiant panel 340 terminate in downward projections 350. Thus, this cross-sectional view across the width of the secondary heat emitter shows a symmetric surface that slopes downward from the centerline (which coincides with the “340” label) of the radiant panel to its perimeter edge and then terminates in a vertical or nearly vertical downward projection. These downward projections help protect the combustion/ignition area (air gap) from the wind and contaminants, and isolates this area to promote faster and more efficient heating.
The slight angle in the shape of the radiant panel 340, which may ideally be in the range of 3-6 degrees, provides many advantages. First, the shape helps the panel maintain its shape at high temperatures. Further, the angled shape has the effect of spreading out the radiant heat over a broader area, thus promoting a uniform temperature distribution. The angled shape also prevents oils, fats, and other cooking by-products from accumulating on the radiant panel 340. Thus, the non-flat, convex shape of the radiant panel 340 provides numerous performance advantages. Alternatively, the slope of the radiant panel may be curved (i.e. curved convex surface) rather than linear (i.e. linear convex surface). Thus, as used herein, the term “convex” refers to a slight protrusion or bulge in the upward direction (towards the grilling surface above and away from the plenum chamber) irrespective of whether the bulge is in the form of a linear or curved surface.
Unlike conventional infrared burners, the flame is effectively enclosed, which provides numerous advantages as well. First, the radiant panel enhances the performance of the infrared burner by reflecting part of the radiant energy back to the surface of the primary emitter (i.e. perforated ceramic grid 335). This allows the burner to heat more rapidly and increases the temperature of the primary emitter for more efficiency. By distributing the combustion gases out the side of the burner, heat is better distributed across the surface of the cooking surface or grille. Moreover, because the radiant panel 340 covers the primary emitter (i.e. perforated ceramic grid 335), it protects the primary emitter from fat, grease and other cooking by-products that may fall through the grille and would otherwise fall onto the primary emitter below and cause blockage of the ports in the perforated ceramic grid which would decrease efficiency. The radiant panel 340 also protects the burner from wind and drafts that would prevent the burner from working efficiently. Finally the radiant panel 340 provides a smooth cleanable surface that is not affected by harsh chemicals such as oven cleaners.
FIG. 4 illustrates a cross-sectional front view through the center of two side-by-side radiant panel burners beneath a grilling surface 475. The depicted cross-section is made through dashed line “B” of FIG. 1, which passes through the width of the radiant panel burner 410. The radiant panel burners 410 comprise a mixer 415, a plenum chamber 430 with interior baffle 431, a perforated ceramic grid 435 with ports 436, and a radiant panel 440. The angled or curved sections of the radiant panel 340 terminate in downward projections 450. The gas/air mixture fed into the plenum chamber 430 and interior baffle 431 via the mixer 415 is evenly distributed and fed through ports 436, reaching the surface of the ceramic grid 435 where ignition occurs. Wavy line 400 indicates said ignition, or surface combustion. From said combustion, substantial levels of radiant heat are propagated upward toward the bottom interior surface of the radiant panel 440, causing high levels of radiant heat to be propagated above and beyond the top exterior surface of the panel 440. Upward motion arrows 401 indicate this rising radiant heat. Meanwhile, a portion of the radiant heat propagated within the space between ceramic grid 435 and panel 440 is returned to the grid 435, for additional heating of the ceramic element. Downward motion arrows 402 indicate this quantity of returned radiant heat. Accompanying these quantities of radiant heat is a portion of convective heat pushed through the open length portions of the radiant panel 440 and upward to a grilling surface. Curved motion arrows 403 indicate this quantity of convectively propagated heat. As described above, each radiant panel 440 is slightly angled (in a linear or curved fashion) and slopes downward from its center toward its terminal lengthwise edges to provide more efficient heat transmission.
FIG. 5 illustrates a perspective top view of a plurality of radiant panel burners placed in a grilling structure. By way of example, a grilling structure 570 with grilling surface 575 utilizes standard methods of high intensity sear-burning, and is especially suited for grilling meats with infrared heat. The grilling structure 570 provides an enclosure for multiple radiant panel burners 510 (of which four are shown), to be placed two to four inches below the grilling surface 575. FIG. 5 shows said radiant panels 510 placed symmetrically into four quadrants of the grilling structure 570, for ideal, even heating results. During operation, high levels of evenly distributed radiant and convective heat rise from the radiant panels 540 of the burners 510 to reach the underside of food items 590 placed on the grilling surface 575. The present invention thus provides a highly propagative yet even transmission of heat for grilling food items, producing highly controlled, high-intensity sear-burning.
While there have been described herein what are considered to be preferred and exemplary embodiments of the present invention, other modifications of the invention shall be apparent to those skilled in the art from the teachings herein. It is noted that the embodiments disclosed are illustrative rather than limiting in nature and that a wide range of variations, modifications, changes, substitutions arc contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of other features. Many such variations and modifications may be considered desirable by those skilled in the art based upon a review of the foregoing description of preferred embodiments. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.