Patent Application
20110104621
The present invention relates to outdoor gas appliances. More particularly this invention relates to pilot igniter systems for outdoor gas appliances such as open fireplaces, barbecues or fire pits.
Outdoor gas appliances such as open fireplaces and barbecues are notorious for the difficulties they present in maintaining an ignition pilot flame for the purpose of igniting the main burners. Since the appliances are outdoors and the primary burner and the adjacent pilot are exposed to the elements, they are subject to environmental conditions, particularly to gusts of wind that tend to extinguish the pilot.
The prior art has seen numerous attempts to overcome this difficulty by designing particular shapes of enclosures for the pilot with a view to isolating the pilot (within the enclosure) from the movement of air around the burners. However as the pilot is adjacent the log set, sand pan, piping or flame distributing structures, the pilot enclosure must fit within a limited space and needs to conform to the location and shapes of the flame distributing elements that crowd it.
Despite the need to fit the pilot enclosure within a limited space and shape, the enclosure must still be large enough in volume to allow a sufficient supply of oxygen to initiate and maintain ignition. Most of such prior art attempts have been unsatisfactory, resulting in unsightly or ineffective enclosure structures that do not prevent blow outs of the pilot.
It is therefore an object of the present invention to provide a pilot ignition system for an outdoor appliance of the type having a burner that is exposed to ambient wind, but that provides improved reliability of the pilot in windy and other environmental conditions.
There is provided a pilot ignition system for an outdoor gas appliance wherein the pilot igniter is isolated from the atmospheric elements such as ambient wind by physically distancing it from the appliance burners. The distance between the pilot and the burner would normally prevent the pilot from igniting the primary burner. According to the preferred embodiment of the invention, this is overcome by providing a jet of gas to a nozzle slightly upstream of the pilot, the jet of gas being directed toward the burner end of the enclosure. The jet of gas is ignited by the pilot resulting in a torch or jet of flame extending from the pilot igniter through the downstream length of the enclosure and to the primary burner. The jet of flame bridges the distance between the pilot and the burner, while the distance itself isolates the pilot igniter from environmental effects in the vicinity of the burner.
According to one aspect of the invention, a pilot ignition system for an outdoor gas appliance comprises a pilot igniter that is isolated from the atmospheric elements by physically distancing it from the appliance burners, and a nozzle for generating a stream of gas past the pilot igniter to create a torch or jet of flame that bridges the distance between the pilot igniter and the burners.
In a more particular aspect of the invention, the pilot igniter and the nozzle are recessed in an elongated enclosure that opens to the burners at a distal end in relation to the pilot igniter and nozzle, the enclosure containing and directing the resulting jet of flame to the burners.
Preferably the elongated enclosure extends into the appliance to an area that is protected from the exterior environment. In this arrangement, the pilot igniter is sufficiently recessed into the enclosure that it is substantially unaffected by gusts of wind occurring in the immediate vicinity of the burners.
The foregoing was intended as a broad summary only and of only some of the aspects of the invention. Other aspects of the invention will be more fully appreciated by reference to the detailed description of the preferred embodiment. Moreover, despite this disclosure, the actual invention, inventive apparatus, methods, concepts and inventive ideas for which this patent is sought are ultimately defined only by the formal claims of this application, not by the details of the summary or of the preferred embodiment.
The invention will be described by reference to the detailed description of the preferred embodiment and to the drawings thereof in which:
The preferred embodiment of the invention is embodied in an outdoor gas barbecue 10, illustrated in
Support structure 12 extends around the pit 14 and defines an air cavity 15 beneath the pit 14. A suitably dampened air inlet 17 is provided in the support structure 12 to allow outside air to communicate with the air cavity 15 and to thereby provide combustion air to the igniter assembly 22.
Gas inlet conduit 20 supplies gas to the igniter assembly 22 and the burners 18. As will be described below, control valve 26 regulates the supply of gas to the burners 18, a pilot igniter 34 (see
The igniter assembly 22 will now be described by reference to
Cylindrical enclosure 24 houses torch tube 32 as well as pilot igniter 34 that extends partially into torch tube 32 through an aperture 36. Enclosure 24 protects and contains the flame elements (torch tube 32 and igniter 34) while also providing controlled damping of turbulence for combustion air. Enclosure 24 includes air inlets 28 providing air communication with air cavity 15 and the bottom of cylinder 24 is also open. Aperture 36 provides air communication between the interior of torch tube 32 and the interior of enclosure 24.
Torch tube 32 is elongated and extends from the bottom of enclosure 24 to the top of enclosure 24, with an outlet opening 33 adjacent the burners 18. The bottom of torch tube 32 is sealed around gas jet supply nozzle 44. Gas jet supply nozzle 44 provides a stream of pressurized gas directed upward along the length of torch tube 32. A venturi sleeve 46 is welded to the inside wall of torch tube 32 and is positioned such that the stream of pressurized gas from the gas jet supply nozzle 44 is directed through the sleeve 46. Pilot igniter 34 is located slightly downstream the venturi sleeve 46.
The pressure supplied through gas jet supply line 42, the dimensions of gas jet supply nozzle 44 and the size of venturi sleeve 46 are chosen such that the resulting stream of pressurized gas will, when ignited by pilot igniter 34, create a torch or jet of flame 29 extending the length of torch tube 32 to the burners 18.
Pilot igniter 34 is supplied by igniter gas supply line 38 and gas is supplied to gas jet supply nozzle 44 through gas jet supply line 42. In operation, automatic valve 26 initiates ignition by first opening igniter gas supply line 38 and triggering ignition of the igniter 34. Once ignition is detected by means of a sensor (not shown), gas jet supply line 42 and burner gas supply line 40 are opened. A jet of flame 29 is generated within torch tube 32 and ignites the burners 18 that are being supplied from burner supply tube 31. As best appreciated by reference to
Once the burners are operational, the automatic gas valve 26 shuts off the gas supply to the pilot igniter 34 and to the gas jet supply nozzle 44.
Due to the remoteness of the pilot igniter 34 from the burners 18 and the outside environment that surrounds them, the invention provides an effective means of avoiding pilot blowout in windy and other environmental conditions, while nonetheless providing an effective ignition system for the main burners.
In alternative embodiments, the entire igniter assembly 22 may be provided without necessarily housing it within a larger air cavity in the gas appliance. The dimensions of the protective enclosure 24 and the air inlets 28, as well as the extent to which the bottom of the enclosure 24 is open may be chosen to substantially provide protection and to control air turbulence at the pilot igniter thereby allowing the igniter assembly to be housed in the open air rather than in a dedicated air cavity beneath the appliance.
Other structural arrangements can be contemplated that provide substantial isolation of the pilot igniter from the elements by physically distancing it from the burners, and the generation of a torch to bridge the distance between them.
It will therefore be appreciated by those skilled in the art that the preferred and alternative embodiments have been described in some detail but that various modifications may be practiced without departing from the principles of the invention.
