Patent Publication Number: US-2011056481-A1

Title: Gas fireplace burner with built-in pilot system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of Canadian Patent Application No. 2,678,231, which was filed on Sep. 8, 2009, and is incorporated herein in its entirety by reference. 
     FIELD OF THE INVENTION 
     This invention relates to an improved ignition system for gas fireplaces. In particular, the invention relates to the arrangement of a pilot burner in relation to the main burner of a gas fireplace and its surrounding structure. 
     BACKGROUND OF THE INVENTION 
     The presence of a pilot to ignite the main burner of a gas fireplace is recognized as a safe means to ignite the main flame, as compared to a ‘direct spark’ ignition system where a spark is used to ignite accumulated gas flowing out of the main burner, sometimes with an unexpectedly large explosion. However the look of pilot burner assembly generally detracts from the aesthetic appeal of the fireplace. For that reason, in traditional gas fireplaces having artificial log sets, the pilot assembly is often intentionally camouflaged by the log set. 
     It is presently in fashion for consumers to seek a clean, modern look for home appliances and furnishings: to that desire, a few years ago the market saw the introduction of a gas fireplace style called a ‘linear burner’. This style of burner provides a contemporary look using rocks or glass beads as a decorative medium around the flame, as opposed to the artificial logs used in traditional gas fireplaces. However, without the logs to act as camouflage, the pilot burner becomes visible in a contemporary look fireplace. 
     The effectiveness of a pilot burner is also subject to it being properly installed. If the pilot burner is placed too far away from the main burner, or too high or too low in relation to it, it may fail to ignite the burner, again resulting in potentially dangerous build up of gas. 
     It is an object of this invention to eliminate the unsightly appearance of a pilot in a gas fireplace, particularly but not exclusively in a linear burner style of gas fireplace, yet retain the safety aspect of a pilot as compared to a direct spark ignition system. 
     It is another object of the invention to avoid the appearance of a separate pilot candle alongside a main burner when the fireplace is in operation, which can occur when the pilot burner assembly is not properly camouflaged. 
     These and other objects of the invention will be better understood by reference to the detailed description of the preferred embodiment which follows. 
     SUMMARY OF THE INVENTION 
     The present invention provides a pilot burner that is directly adjacent and provides a flame that appears as a continuous extension of the flame from the main linear burner. The pilot burner is provided within the linear burner enclosure that otherwise directs gas from the gas supply toward a linear series of openings at the top of the enclosure. By being situated within the main burner enclosure, the pilot burner is effectively invisible to the user. 
     The invention retains the safety characteristics of the pilot over the direct spark ignition system, while avoiding the unsightliness of the pilot burner and eliminating the candle effect of a pilot flame spaced from the main burner. 
     In one aspect, the invention comprises a burner and pilot assembly for a gas fireplace comprising a substantially hollow burner enclosure, a plurality of burner outlet apertures at the top of the enclosure, a pilot burner mounted within a portion of the enclosure. The pilot burner underlies a portion of the outlet apertures such that flame from the pilot burner extends from some of the outlet apertures. 
     In a more specific aspect of the invention, the pilot burner is mounted in a walled compartment within the main burner enclosure. 
     In a further aspect, the main burner enclosure comprises a bottom plate that also acts as the bottom portion of the walled compartment which also includes at least one air inlet aperture. 
     In yet a further aspect, a venturi element is provided to control the inlet of combustion air to a portion of the compartment that contains the outlet of the pilot burner. 
     In another aspect, the invention comprises the foregoing features as applied specifically to a linear style burner. 
     The foregoing was intended as a broad summary only and of only some of the aspects of the invention. It was not intended to define the limits or requirements of the invention. Other aspects of the invention will be appreciated by reference to the detailed description of the preferred embodiment and to the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described by reference to the detailed description of the preferred embodiment and to the drawings thereof in which: 
         FIG. 1  is a perspective view of a prior art linear style burner for a gas fireplace; 
         FIG. 2  is a perspective view of the linear style burner according to the preferred embodiment of the invention; 
         FIG. 3  is an exploded view of the burner of  FIG. 2 ; 
         FIG. 4  is a plan view of the burner of  FIG. 2 ; 
         FIG. 5  is a cross-sectional view of the burner of  FIG. 4  taken along line  5 - 5 ; and, 
         FIG. 6  is a right end view of the burner of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  illustrates a ‘linear burner’ style gas fireplace assembly. The assembly generally consists of a substantially hollow burner  10  and a pilot assembly  12 . 
     Hollow burner  10  comprises opposed inclined side plates  14  (only one of which is visible in  FIG. 1 ), opposed end plates  16  (only one of which is visible in  FIG. 1 ), a top burner plate  18  having a series of linear apertures  20 , and a bottom burner plate (not shown in  FIG. 1 ). The bottom burner plate accommodates a gas supply conduit  22  for supplying gas to the hollow interior of the burner  10 . The gas is collected within the hollow burner enclosure and exhausted through the apertures  20  at the top of the burner. 
     Pilot assembly  12  includes a bracket  24  for mounting the assembly to the side of the burner  10 . A pilot burner  26  and pilot flame diverter  28 , a pilot igniter  30  and a pilot flame sensor  32  are mounted in bracket  24 . 
     In use, this style of burner would be partly covered with rocks or glass beads to barely cover the top burner plate  18 . It will be appreciated that in such configuration, the pilot burner  26  and diverter  28  remain visible, as well as presenting a distinctly separate candle-like flame besides the flame generated by the burner  10 . 
       FIGS. 2 to 6  illustrate the preferred embodiment of the present invention. The hollow burner  34  consists of opposed inclined side walls  36 ,  38 , a top burner plate  40  having linear apertures  42 , opposed end walls  44 ,  46  and a bottom burner plate  48 . Bottom burner plate  48  includes an aperture  50  for receiving gas supply conduit  52 . 
     The pilot burner  54  is mounted within an aperture  56  that is provided in bottom burner plate  48  alongside air inlets  58 . A divider plate  60  isolates the pilot burner  54  and the pilot flame from the main portion of the enclosure  62 . A venturi bracket  64  regulates the mixing of combustion air supplied through air inlets  58  and of the gas emitted from the outlet of pilot burner  54 . Pilot burner  54  and its associated venturi bracket  64  are therefore enclosed in a compartment between divider plate  60  and end wall  44  and are not visible from the exterior of the burner  34 . 
     In the preferred embodiment, pilot flame sensor  66  and pilot igniter  68  are mounted to end wall  44  by means of a bracket  70 . 
     When the pilot burner is lit, the pilot flame extends upward from the apertures in the portion of the top burner plate  40  that directly overlies the pilot burner  54 . When the burner  34  is lit, the pilot flame therefore appears to be a continuous and integral extension of the flame emitted from main burner  34 . In addition, as the pilot burner  54  is now supplied integrally with the housing of burner  34 , there is little possibility of incorrect positioning of the pilot burner in relation to the main burner thereby ensuring reliable ignition of the main burner. 
     It will be appreciated by those skilled in the art that the preferred embodiment has been described in some detail but that certain modifications may be practiced without departing from the principles of the invention.