Abstract:
A convertible burner for gas-fueled cigarette pocket lighters for use with flint and wheel ignition, the burner including a burner body having a central gas fuel passageway and an air inlet channel in fluid communication with the central passageway and may have a plurality of integrally formed passageways around the periphery of the burner body. An air control structure in the form of a collar is movable to a first position with respect to the burner body to close the air inlet channel and form a post-mix burner for flint and wheel ignition, and to a second position with respect to the burner body to admit air via the air inlet channel to form a pre-mix burner after ignition. The relative movement can be longitudinal or peripheral, and the peripheral movement can be circumferential. In one embodiment, the collar surrounds and is immediately adjacent to the air inlet channel.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the benefit of U.S. Provisional Application No. 60/519,144, filed Nov. 10, 2003, the entire contents of which are incorporated by reference. 
     
    
     FIELD OF INVENTION  
       [0002]     The present invention relates to cigarette or pocket lighters generally, and specifically to pocket lighters with flint and striking wheel ignition.  
       BACKGROUND OF THE INVENTION  
       [0003]     There are two primary types of gas-fueled pocket lighters presently available. The first type of gas-fueled device utilizes a post-mix burner. Post-mix burners pull oxygen for combustion from the air surrounding the gas outlet. This combustion type is characterized by a low velocity, low temperature yellow flame sometimes referred to as a traditional or lazy flame.  
         [0004]     A second type of gas-fueled device is a pre-mix burner. This type of burner pulls oxygen for combustion through holes in the base of the burner and combines the oxygen and fuel prior to combustion. This combustion type is characterized by a high velocity, blue flame. These burners, by virtue of their improved efficiency, provide higher flame temperatures, and more complete combustion. The devices are commonly referred to as blue flame, torch flame, or invisible flame, lighting devices.  
         [0005]     There are two primary ignition systems that are typically used with gas-fueled cigarette or pocket lighters. The first type is the flint and wheel ignition mechanism. A hardened striking wheel is rotated against a flint made of a pyrophoric material. The engagement of the striking wheel with the flint produces a spark that ignites the fuel as it leaves the gas outlet. Another type of ignition system is piezoelectric. In this type of ignition system, a high voltage charge is generated when a crystal is struck. A spark is created when this charge jumps across a preset gap between an electrical contact and the gas nozzle (which is constructed of a conductive material). This spark ignites the gas as it leaves the nozzle.  
         [0006]     The pre-mix burners offer advantages over post-mix burners including better efficiency of combustion, higher heat, and higher velocity, which makes the flame more stable and less likely to be blown out by the wind. The flint and wheel type ignition offers some advantages over piezoelectric ignition systems including being more reliable and consistent, and less costly to produce. Attempts to combine the pre-mix burner with flint and wheel ignition have met the following difficulties. Because of the velocity of the pre-mix burner, it is difficult to ignite the air/fuel mixture with flint and wheel type ignition systems. Also, the dust and debris generated by the flint and wheel ignition system has a tendency to accumulate and clog the air orifices and the gas orifice on the pre-mix burner.  
         [0007]     To overcome the above drawbacks, devices have been developed to incorporate a dual i.e., separate burner approach in combination with the flint and wheel ignition. These devices generally offer the following features. First, the device can provide both a post-mix and a pre-mix flame from the same device or lighter, but using separate burners. Some of these devices utilize a flint and striking wheel and others use piezoelectric ignition. In addition, some devices ignite one burner and then utilize the existing flame to ignite the other burner. The dual burner approach suffers from drawbacks including increased complexity, and therefore increases the cost with an adverse effect on reliability. Accordingly, what is needed is a gas operated pocket lighter that combines a single burner capable of operating as a pre-mix burner along with the flint and wheel ignition system.  
       SUMMARY OF THE INVENTION  
       [0008]     The present invention meets the above-described need by combining the functions and features of a pre-mix and post-mix burner into a single burner. When used in conjunction with a flint and wheel ignition, the ignition cycle is staged so that the post-mix burner is ignited first. Once ignition occurs, the post-mix flame is converted to a pre-mix flame in the second stage. Because a single convertible burner is used, there is no need for redundant components or parallel gas delivery systems. The conversion from pre-mix to post-mix burner for ignition is accomplished by closing the air supply orifices to the burner. Conversely, the conversion from the post-mix configuration to the pre-mix configuration is accomplished by opening the air supply for the pre-mix mode of the burner. Furthermore, it has been found that the conversion from post-mix to pre-mix may be accomplished quite rapidly, while still maintaining reliable post-mix ignition and subsequent pre-mix combustion.  
         [0009]     In one aspect the present invention includes a convertible burner for a gaseous fuel lighter having a burner body assembly having central passageway therethrough. The gaseous fuel is preferably butane or a similar fuel, capable of storage in the lighter as a liquid, while changing to a gas phase for combustion. The fuel may include one or more alkane hydrocarbons, such as butane alone or a combination of butane and propane. The burner body may have a plurality of peripheral passageways located about the periphery thereof. A burner body assembly may include the burner body and a housing supporting the burner body, with the housing having at least one air inlet channel in fluid communication with the central passageway. The burner also includes a collar surrounding at least a part of the burner body assembly having the air inlet channel. The burner body assembly and the collar are relatively movable with respect to each other to selectively block and unblock fluid communication between the air inlet channel and the external air environment. The burner is convertible between a post-mix configuration when the fluid communication is blocked and a pre-mix configuration when the fluid communication is unblocked. In one aspect of the present invention, the central passageway has a longitudinal axis and the relative movement between the burner body assembly and the collar is colinear with the longitudinal axis. A flint and wheel ignition system is used with the convertible burner to ignite a post-mix flame which the convertible burner then transforms into a pre-mix flame with the same burner.  
         [0010]     In another aspect, the present invention may include a method of using a flint and wheel ignition system to ignite a flame in a single burner of a lighter in the post-mix configuration and then transforming the burner to the pre-mix configuration. The method may include the steps of providing the burner body having the central passageway therethrough and may include providing the plurality of peripheral passageways at a periphery of the burner body, and at least one air inlet channel. The method may also include surrounding at least the part of the burner body or burner body assembly which has the air inlet channels with the collar. In the first relative position between the collar and the burner body, the burner is in the post-mix configuration wherein the collar blocks air from entering the central passageway and the plurality of air inlet channels. Ignition using the flint and wheel occurs in the post-mix configuration, with fuel passing through the central passageway not mixed with air until after the fuel exits the burner body. A further step in the method of operation may include causing a second relative position between the collar and the burner body wherein the collar permits air to enter the central passageway and the plurality of air inlet channels such that the burner body and collar form a pre-mix configuration. In the pre-mix configuration, fuel passing through the central passageway is mixed with air before exiting the burner body.  
         [0011]     In another aspect, the present invention may include a method of making a flint and wheel ignited single burner for a gaseous fuel lighter, with the burner capable of operating initially in the post-mix configuration during ignition and then transforming to pre-mix configuration. The method may include the steps of providing the burner body assembly having at least the burner body, with the assembly having a central passageway therethrough. A part of the burner body assembly has at least one air inlet channel in fluid communication with the central passageway, and the method may further include providing a collar sized to closely interfit with at least the part of the burner body assembly having the at least one air inlet channel, and assembling the burner body assembly and the collar together in a loose-fitting relationship so that the burner body assembly is movable relative to the collar after assembly. In this aspect, the burner can selectively block air in the external air environment from passing through the at least one air inlet channel to mix with fuel in the central passageway when the burner body assembly and collar are in a first relative position during which ignition is accomplished by the flint and wheel ignition system. Furthermore, the burner can thereafter selectively admit air from the external air environment through the at least one air inlet channel to mix with fuel in the central passageway when the burner body assembly and collar are in a second relative position. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     The invention is illustrated in the drawings in which like reference characters designate the same or similar parts throughout the figures of which:  
         [0013]      FIG. 1  is a simplified view partly in section of a first embodiment of the burner in a post-mix configuration.  
         [0014]      FIG. 2  is a view similar to that of  FIG. 1 , except with the burner in a pre-mix configuration.  
         [0015]      FIG. 3  is a simplified view partly in section of a second embodiment of the burner of the present invention.  
         [0016]      FIG. 4  is a section view of a burner corresponding to that of  FIG. 3 , shown in a post-mix configuration.  
         [0017]      FIG. 5  is a section view of the burner corresponding to that of  FIG. 3 , except shown in a pre-mix configuration.  
         [0018]      FIG. 6  is a more detailed view of a burner of the present invention according to the first embodiment shown in a post-mix configuration.  
         [0019]      FIG. 7  is a view of the burner of  FIG. 6 , except shown in a pre-mix configuration.  
         [0020]      FIG. 8  is a top plan view of a burner body and partially cutaway view of a diffuser ring useful in the practice of the present invention.  
         [0021]      FIG. 9  is a perspective view of the burner body of  FIG. 8 .  
         [0022]      FIG. 10  is a view similar to that of  FIG. 6 , except for an embodiment having a burner assembly without a diffuser ring, shown in a post-mix configuration.  
         [0023]      FIG. 11  is a view of the embodiment of  FIG. 10 , except shown in a pre-mix configuration.  
         [0024]      FIG. 12  is a view of the embodiment of  FIG. 10  shown with the flint and wheel ignition system.  
         [0025]      FIG. 13  is an enlarged view of the embodiment of  FIG. 10  shown with another flint and wheel ignition system.  
         [0026]      FIG. 14  is a view similar to that of  FIG. 13 , except with additional parts of the lighter shown to illustrate a way of switching the burner from a post-mix configuration to a pre-mix configuration. 
     
    
     DETAILED DESCRIPTION  
       [0027]     Referring to the Figures and most particularly to  FIG. 1 , the burner  10  of the present invention includes a centrally disposed gas fuel passageway  13  surrounded by a plurality of peripheral passageways  16 . The centrally disposed gas fuel passageway  13  is disposed in the center of a burner body  19  that is constructed of a suitable material. The peripheral passageways  16  are integrally formed about the perimeter of the burner body  19  which is shown in a round configuration. It will be evident to those of ordinary skill that other shapes for the body  19  may also be suitable such as square, rectangular, etc.  
         [0028]     The central passageway  13  is in fluid communication with and includes an extension  13 ′ in a housing  108  holding the burner body  19 . Central passageway  13  is in fluid communication with a valved fuel reservoir (not shown) that typically contains a combustible fuel such as butane (or a similar fuel) under pressure to keep the fuel in the liquid phase in the reservoir. It is to be understood that the passageway  13  in the burner body  19  and the extension  13 ′ in the housing together constitute an overall central passageway. The operation of the reservoir will be evident to those of ordinary skill in the art, and therefore is not discussed in detail herein. Once the fuel exits the reservoir, it changes to the gas phase, and travels through passageway  13 , exiting where the flame  23  is shown in  FIG. 1 . A flint and wheel igniter system, which may be of the type disclosed in U.S. Pat. No. 6,247,920 (assigned to the assignee of the present invention and the entire contents of which are incorporated herein by reference), is used to ignite the gaseous fuel as it exits the passageway  13 . The flint and wheel ignition system will be described in more detail in connection with  FIGS. 12 and 13 . The burner  10  is mounted such that the opening of passageway  13  is disposed in operative relation to the flint such that sparks from the flint are capable of igniting the gas as it exits passageway  13 . The burner assembly of the burner body  19  and housing  108  has at least one air inlet channel  114  in fluid communication with central passageway  13 , more particularly, with the extension  13 ′ of passageway  13 .  
         [0029]     In the configuration of a first position  120  shown in  FIG. 1 , the burner  10  operates as a post-mix burner because the air inlet channels  114  are closed off by a collar  110 . The flint and striking wheel combination ignites the gas exiting the passageway  13  and draws oxygen from the air surrounding the exit to produce a post-mix or yellow flame  23 . While the passageways  16  are shown open to a plenum  106  upstream of the burner body  19  in  FIG. 1 , it is to be understood that the gaseous fuel will propagate through and be ignited at the outlet of passageway  13  in burner body  19 , but not through passageways  16  in the post-mix configuration of position  120  shown in  FIG. 1 .  
         [0030]     The collar  108  slides back and forth between the positions shown in  FIGS. 1 and 2  along a longitudinal axis indicated by arrows  25 . The longitudinal axis is defined by the central passageway  13  and is parallel to arrow  116  which represents the fuel flow through central passageway  13 .  
         [0031]     Turning to  FIG. 2 , when the collar  108  is moved to a second position  122 , one or more air inlet apertures  112  in collar  110  are aligned with air inlet channels  114 , providing fluid communication therebetween and to an external ambient air environment  130  such that air can enter along arrows  118  and mix with the fuel passing through the central passageway  13  to provide a pre-mix burner capable of producing a pre-mix or blue flame  26 .  
         [0032]     As will be evident to those of ordinary skill in the art based on the following disclosure, the collar  108  may be biased in the configuration  122  shown in  FIG. 2  by a resilient member such as spring or the like. During the ignition stage, an actuating mechanism such as a hand operated lever or push button would enable the user to overcome the resilient member so than the collar  108  moves into the position  120  shown in  FIG. 1 . After the flint and wheel (or other igniter) ignite the flame, the actuating mechanism would be released and the collar  108  would automatically return to the configuration  122  of  FIG. 2  where it operates as a pre-mix burner. As an alternative, the collar  108  can be moved back and forth between the two positions  120  and  122  manually. As a still further alternative, the burner may be biased to the post-mix configuration  120 , and selectively operable to move to the pre-mix configuration  122 .  
         [0033]     Turning to  FIGS. 3, 4 , and  5 , an alternate embodiment of the invention includes a collar  110  that rotates in the direction of arrow  102  between a closed position ( FIG. 3 ) and an open position ( FIG. 4 ). The collar  110  is provided with a plurality of apertures  112  that are capable of rotating in and out of alignment with the air inlet channels  114 . The arrow  102  indicates that collar  110  moves peripherally (more particularly collar  110  moves circumferentially) with respect to housing  108  and burner body  19 . It is to be understood that while a cylindrical configuration for the collar  110  and a reduced diameter portion  126  is shown in  FIGS. 3, 4 , and  5 , the collar  110  and portion  126  may have contiguous shapes other than cylindrical, while still permitting relative motion therebetween, to open and close the path between the air inlet apertures  112  in the collar  110  and the air inlet channels  114  in the housing  108 . Specifically, “peripheral movement” here means movement of the apertures  112  into and out of alignment with channels  114 , to open and close an airway path between the external air environment  130  and the central passageway  13 .  
         [0034]     With collar  110  in the first position  120 , shown in  FIG. 4 , the airway path from the external air environment  130  to air inlet channels  114  is substantially blocked by peripheral or circumferential intentional misalignment of the air inlet apertures  112  with channels  114 . In other words, a solid portion of collar  110  blocks off air from entering the channels  114 , when the collar  110  is in the first position  120 , as shown in  FIG. 4 . With the collar  110  in the first position  120 , when fuel is delivered through the central passageway  13  and ignited, a yellow flame  23  will result. In the configuration  120  shown in  FIG. 4 , the burner  10  operates as a post-mix burner. The flint and striking wheel combination ignites the gas exiting the passageway  13  and draws oxygen from the air surrounding the exit to produce the post-mix yellow flame  23 .  
         [0035]     When the collar  110  is moved relative to housing  108 , either circumferentially or peripherally, to the second position  122  shown in  FIG. 5 , and fuel is delivered through the central passageway  13 , air from the external air environment  130  will enter the air inlet apertures  112  in the collar  110  and flow through the air inlet channels  114 , after which it will mix with the fuel in the central passageway  13 , after which it will pass through the burner body  19 , both through central passageway  13  and through peripheral passageways  16 . When ignited, the air and fuel mixture exiting burner body  19  will combust with a blue flame pattern  26 . More particularly, the blue flame pattern  26  includes a principal blue flame at the exit of the central passageway  13 , and (optionally) may include a plurality of auxiliary blue flames at the exits of the passageways  16  in the burner body  19 .  
         [0036]     In the configuration or position  122  shown in  FIG. 5 , the burner  10  operates as a pre-mix burner. With the collar  110  disposed in the position  122  shown in  FIG. 5 , air can travel from the external air environment  130  in the direction of arrows  118  to enter the air inlet apertures  112  and pass through the air inlet channels  114  to mix with fuel gas in the central passageway  13  prior to ignition.  
         [0037]     As will be evident to those of ordinary skill in the art based on reading this disclosure, the rotating collar  110  may be biased to the position  122  shown in  FIG. 5  by a resilient member such as a spring or the like. An actuating mechanism such as a lever or button may be utilized to overcome the force of the resilient member to move the collar into the position shown in  FIG. 4  during ignition. After the gas is ignited by the flint and striking wheel or other igniter, the mechanism may be released and the collar automatically returned to the position shown in  FIG. 5 . As an alternative, the collar  110  may be rotated between the two positions manually. As a still further alternative, the burner  10  may be biased to the post-mix configuration  120 , and selectively operable to move to the pre-mix configuration  122 .  
         [0038]     It may thus be seen that in  FIGS. 1 and 4 , air inlet apertures  112  in collar  110  are purposely misaligned with air inlet channels  114  in housing  108  in position  120 , preventing air from entering and mixing with the fuel, indicated by arrow  116 , in the central passageway  13 . When the collar or choke  110  is moved relative to the burner body  19  and housing  108  to the position  122  shown in  FIG. 2  or  5 , air inlet apertures  112  are aligned with air inlet channels  114 , permitting air to enter through the fluid communication path established with the external air environment  130 , as indicated by arrows  118 , where it mixes with the fuel indicated by arrow  116  in the central passageway  13 .  
         [0039]     Referring now to  FIGS. 6, 7 ,  8 , and  9 , a more detailed view of the present invention according to the first embodiment may be seen. In  FIG. 6 , the burner  10  is in the first position or post-mix configuration  120  and will produce the yellow or “lazy” flame arrangement. In  FIG. 7 , the burner  10  is in the second position or pre-mix configuration  122  and will produce the blue or “torch” flame arrangement.  FIG. 8  is a top view of a burner body  119  and a partially cutaway diffuser ring  140 . The burner body  119  and diffuser ring  140  are shown in side section view in  FIGS. 6 and 7  as taken along line  6 - 6  of  FIG. 8 .  FIG. 9  shows a perspective view of the burner body  119 .  
         [0040]     In  FIG. 6 , an air control structure in the form of a collar  210  blocks the airway path from the external air environment  130  because the air inlet apertures  112  in collar  210  are not in fluid communication with the air inlet channels  114  in housing  132 . In  FIG. 7 , the air inlet apertures  112  open the airway path from the external air environment  130  to the central or primary passageway  13  via chamber  134  and air inlet channels  114 . It is to be understood that while air inlet apertures  112  are shown in  FIGS. 6 and 7  aligned with an axis  138  of the air inlet channels  114 , alternatively the air inlet apertures  112  may be located otherwise, for example, along an axis  136  perpendicular to the axis  138 , with each of axes  136  and  138  perpendicular to the longitudinal axis  124 . A burner body  119  (similar to the simplified burner body  19  shown in  FIGS. 1-5 ) is provided with a diffuser ring  140 . Diffuser ring  140  is preferably press-fit on a shoulder  142  of burner body  119 . Burner body  119  is preferably gear-shaped (as may be seen more clearly in  FIGS. 8 and 9 ) and has an internal counterbore  144  located at the upstream end thereof. The counterbore  144  provides fluid communication between central passageway  13  and peripheral passageways  16 . In  FIGS. 6 and 7 , burner body  119 , diffuser ring  140  and housing  132  together make up the burner or burner assembly for this embodiment.  
         [0041]     In one aspect of the embodiment shown in  FIGS. 6 and 7 , auxiliary air may be permitted to enter the burner assembly radially inwardly at an auxiliary air inlet between a lower edge of the diffuser ring  140  and an upper edge of the housing  132 . When present, the auxiliary air inlet is to be understood to be in fluid communication with the peripheral passageways  16 . Alternatively, diffuser ring  140  may be elongated or repositioned to prevent entry of such auxiliary air by omitting the auxiliary air inlet from the burner assembly.  
         [0042]     Referring now most particularly to  FIGS. 10 and 11 , an alternative embodiment of the present invention may be seen. In this embodiment, the diffuser ring is omitted, and the burner body  219  and housing  132  together make up the burner body assembly. In this embodiment, the burner body  219  may be the same as burner body  119  shown in  FIGS. 6-9 , except that the upper portion forming shoulder  142  may be removed. In addition, the counterbore  144  on the bottom of the burner body  219  may also be omitted, provided that a clearance is provided below the burner body  219  and housing  132 .  
         [0043]     Referring now to  FIG. 12 , a burner  10  according to the present invention is shown in a cut away view of the lighter of U.S. Pat. No. 6,247,920. In  FIG. 12 , a flint and wheel ignition system  224  includes a flint wheel  226  and a flint  228 . A windscreen  230  surrounds the area above the burner  10 . In  FIG. 12 , the burner  10  is shown in the post-mix configuration in which rotation of the flint wheel  226  will cause sparks from the flint  228  to ignite a yellow post-mix flame in the area above the burner  10  surrounded by the windscreen  230 , when fuel is provided to burner  10  by a gas valve (not shown). After ignition, the burner  10  may be shifted to the pre-mix configuration to provide a blue flame, as described above.  
         [0044]     Referring now to  FIG. 13 , burner  10  is shown with the flint wheel  226  and flint  228  in an enlarged and more detailed view. As with  FIG. 12 , the burner is shown in a post-mix configuration. When fuel is provided to burner  10 , sparks from flint  228  caused by rotation of wheel  226  will ignite a yellow flame at burner  10 , after which the burner  10  may be shifted to the pre-mix configuration.  
         [0045]     Referring now to  FIG. 14 , additional details of the operation of the present invention may be seen. In the view shown in  FIG. 14 , a pushbutton  232  is formed as an extension of or connection to the collar  210 . As the user&#39;s thumb is rotating wheel  226 , it will begin depression of pushbutton  232  opening a gas valve (not shown) to supply fuel to burner  10  in the post-mix configuration. Sparks from flint  228  will ignite a yellow flame at the outlet of burner  10 . Continued travel of pushbutton  232  will move collar  210  with respect to housing  132  to align the air inlet apertures  112  with the air inlet channels  114 , converting burner  10  to a pre-mix configuration, such as that shown in  FIG. 7  or  11 . Release of pushbutton  232  will stop delivery of fuel to the burner  10 , and allow the burner  10  to return to the post-mix configuration.  
         [0046]     In the embodiments shown, it may be noted that the burner body and housing together make up a burner body assembly. The burner body assembly may also include a diffuser ring. Once assembled, the burner body assembly or burner preferably forms a unitary structure and the relative movement to achieve the post-mix and pre-mix configurations is preferably between the collar or other air control structure and the burner body assembly for such embodiments of the present invention. In  FIGS. 10 and 11 , fuel flow is indicated by solid arrows  220 , air flow is indicated by dashed arrows  222 , and air-fuel mixture flow is indicated by dot-dashed arrows  224 . It is to be understood that the flow paths indicated in  FIGS. 10 and 11  are applicable to  FIGS. 6 and 7 . In  FIG. 10 a  post-mix configuration is shown in which air will combine with the fuel only after the fuel exits the burner body  219 , resulting in a yellow or “lazy” flame type combustion once ignited. In  FIG. 11 a  pre-mix configuration is shown in which air combines with fuel within the burner body assembly before it exits the burner body, resulting in a blue or “torch” flame type combustion once ignited.  
         [0047]     In contrast to some prior art designs, the burner of the present invention may be distinguished by the absence of air inlets to the burner in the post-mix configuration. In the practice of the present invention only air mixing from the environment adjacent the exit or outlet of the burner is relied upon for combustion of the yellow flame. While clearance is shown between the housing  132  and collar  210  in  FIGS. 6 and 10 , it is to be understood that such clearance is insufficient to admit air to the air inlet channels  114  to support pre-mix combustion with in the position or configuration shown in  FIGS. 6 and 10 . In the practice of the present invention the combustion chamber made up of the burner body  119  and surrounding sleeve  222  is entirely closed off except for except for passages  13  and  16 .  
         [0048]     While the invention has been described in connection with certain embodiments, it is not intended to limit the scope of the invention to the particular forms set forth, but, on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims. For example and not by way of limitation, while separate longitudinal and circumferential movement between the collar and the burner body or housing has been described above, it is also contemplated that a combined movement, such as helical or sequential longitudinal and circumferential or peripheral movements may be used while still remaining within the scope of and practicing the claimed present invention wherein a single burner is operable in either a post-mix or a pre-mix configuration. Furthermore by way of example and not by way of limitation, the central passageway may be made up of a primary passageway that is not centered, or by a plurality of passageways, provided that there is at least one passageway selectively connected to the source of combustible fuel. Similarly, only one selectively openable air inlet aperture in fluid communication with the fuel passageway is necessary for the practice of the present invention, notwithstanding that various embodiments show multiple air inlet apertures.