WO2010002826A1

WO2010002826A1 - Gas burner assembly with gas collector and igniter

Info

Publication number: WO2010002826A1
Application number: PCT/US2009/049146
Authority: WO
Inventors: Eric Schlosser
Original assignee: Weber-Stephen Products Co.
Priority date: 2008-07-02
Filing date: 2009-06-30
Publication date: 2010-01-07
Also published as: AU2009267117A1; ZA201100652B; US20100003626A1; CL2010001579A1; CN102084185A; CA2729706A1; EP2294337A1; AR074162A1; MX2010014348A; BRPI0913922A2

Abstract

Various embodiments of a gas burner igniter assembly are shown, described, and claimed herein. One embodiment of an igniter comprises an electrode at least partially encapsulated in an insulating body. The body of the igniter includes a sleeve portion and a hood portion, whereby the hood portion is disposed in close proximity to an outlet port of a gas burner. The body of the igniter, including the hood portion, is made from a non-conductive and heat and corrosion resistant material to withstand the harsh conditions to which it is subjected. The hood portion is configured to at least partially surround and cover a tip of the electrode, thereby facilitating an accumulation of a combustible gas/air mixture near the electrode. The sleeve portion is an elongated tubular member which is connected to a lead wire at a first end and the hood portion at the second end. The gas burner igniter assembly includes a bracket for holding the igniter in close proximity to the gas burner.

Description

TITLE

GAS BURNER ASSEMBLY WITH GAS COLLECTOR AND IGNITER

FIELD OF THE INVENTIONS The embodiments described and claimed herein relate generally to ignition systems for gas-fired barbecue grills. More specifically, some embodiments relate to corrosion resistant gas collector for a gas burner igniter.

BACKGROUND OF THE INVENTIONS Electronic igniters for barbecue grills are well known in the art. Many prior art igniters, such as those described in U.S. Patents 4,1241,817 ("the '817 patent") and 6,749,424 ("the '424 patent), use an electric potential to create a ignition spark which travels between an electrode and a ground surface. The specific devices described in the '817 and '424 patents utilize gas collector boxes, which are disposed in close proximity to a gas burner, for capturing a combustible gas/air mixture for an igniter. The igniters of the '817 patent and '424 patents generally comprise a gas collector box, an insulated electrode and a ground wire which is attached to the collector box, whereby the ignition spark is intended to travel between the electrode and the collector box. The electrodes of the '817 and '424 patents are insulated with a ceramic sleeve which prevents sparks from occurring at unintended locations. The collector boxes of the '817 and '424 patents are constructed from thin- walled sheet metals. While the prior art ignitions systems, such as those briefly described above, provide an adequate means for igniting barbecue grills, the prior art systems suffer from previously unresolved problems. For example, the prior art collector boxes tend to quickly degrade or rust, as they are subjected to extremely harsh conditions in use. By design, the prior art collector boxes serve as a ground for the igniter and are disposed in close proximity to the burners. As such, the prior art collector boxes are repeatedly subjected to sparks from the electrode and extreme heat from the burner tube.

SUMMARY OF THE INVENTIONS

The various embodiments shown and described herein solve at least some of the above- mentioned problems of the prior art. For example, one embodiment of a gas burner assembly comprises a gas burner, an igniter, an ignition device, and a bracket. The igniter has a ceramic body and electrode. The ignition device is configured to generate a spark between the electrode and a ground. The gas burner includes at least one port for providing a combustible gas. The bracket is configured to position the gas collector portion of the igniter in close proximity to the burner port. The ceramic body of the igniter includes a gas collection portion which is configured to capture at least some of the combustible gas from the burner port. A second embodiment of a gas burner assembly also includes a gas burner, an igniter, an ignition device, and a bracket. The gas burner provides a combustible gas through at least one port. The igniter includes a body and an electrode. The igniter body is made from a non- conductive and heat and corrosion resistant material and has an insulating sleeve portion and a hood portion, which are integral. The sleeve portion has a first end and a second end and the hood portion depends from the second end of the sleeve portion. The electrode extends through the sleeve portion from the first end to the second end, where the electrode extends outside of the sleeve portion into a partially enclosed volume defined by the hood portion. The insulating portion of the igniter body is configured to prevent sparks at undesired locations and the hood portion is configured to capture at least some of the combustible gas emanating from the burner.

The ignition device is configured to generate a spark between the electrode and a ground. The bracket is configured to position the gas collector portion of the igniter in close proximity to the burner port.

A third embodiment of a gas burner assembly comprises a gas burner, an electrode, a ground, a hood, and an ignition device. The gas burner provides a combustible gas through at least one port. The electrode is positioned above the gas burner and is in close proximity to the ground. The hood is disposed at least partially above the electrode and is made from a ceramic material. The hood has at least one wall which at least partially encloses a volume for capturing at least some of the combustible gas. The ignition device generates a spark between the electrode and the ground.

A fourth embodiment of a gas burner assembly is for a barbecue grill. The gas burner assembly includes a gas burner tube, an igniter, an ignition device, a bracket, and a grounded lead wire. The gas burner tube has a plurality of spaced apart ports for providing a combustible gas. The igniter includes a body and an electrode, wherein the body is made from a ceramic material and has an insulating sleeve portion and a hood portion. The hood portion having at least one wall which at least partially encloses a volume. The sleeve portion has a first end and a second end and the hood portion depends from the second end of the sleeve portion. The electrode extends through the sleeve portion from the first end to the second end, where the electrode extends outside of the sleeve portion into the volume defined by the hood portion. The insulating portion of the igniter body is configured to prevent sparks at undesired locations and the hood portion is configured to capture at least some of the combustible gas emanating from the burner. The ignition device is configured to generate a spark between the electrode and a ground. The bracket is configured to position the gas collector portion of the igniter in close proximity to the burner port and includes a first portion for engaging with the igniter and a second portion for engaging with the burner tube. The grounded lead wire is functionally interconnected with the burner tube, whereby the burner tube is the ground.

Some of the embodiments described above include an insulating sleeve and a gas collector which are integrally cast from a ceramic or other non-conductive and heat and corrosion resistant material. Such a construction provides significant advantages as compared to the sheet metal gas collectors of the prior art. For example, the non-conductive and heat and corrosion resistant material provides the gas collector with a much longer life than the metal gas collector boxes of the prior art. Moreover, because at least some igniter assembly designs require a ceramic material for insulating the electrode anyway, the additional cost for integrally molding the gas collector is minimal.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, objects, and advantages of the inventions described and claimed herein will become better understood upon consideration of the following detailed description, appended claims, and accompanying drawings where:

Figure 1 is a perspective view of a first burner tube ignition assembly which includes a first embodiment of a ceramic igniter and a first embodiment of a bracket for holding the igniter;

Figure 2 is a side view of the same;

Figure 3 is a bottom view of the first embodiment of the ceramic igniter;

Figure 4 is a sectional view of the same; Figure 5 is a perspective view of a second embodiment of a bracket for holding an igniter;

Figure 6 is a perspective view of a second burner tube ignition assembly which includes a first embodiment of a ceramic igniter and a third embodiment of a bracket for holding the igniter; Figure 7 is a close up perspective view of the third embodiment of the bracket;

Figure 8 is a perspective view of a third burner tube ignition assembly which includes a first embodiment of a ceramic igniter and a fourth embodiment of a bracket for holding the igniter;

Figure 9 is a sectional view of the third burner tube ignition assembly; Figure 10 is a first close-up perspective view from the front of the fourth embodiment of the bracket; and,

Figure 11 is a second close-up perspective view from the rear of the fourth embodiment of the bracket.

It should be understood that the drawings are not necessarily to scale and that the embodiments are sometimes illustrated by graphic symbols, phantom lines, diagrammatic representations and fragmentary views. In certain instances, details which are not necessary for an understanding of the embodiments described and claimed herein or which render other details difficult to perceive may have been omitted. It should be understood, of course, that the inventions described herein are not necessarily limited to the particular embodiments illustrated. Indeed, it is expected that persons of ordinary skill in the art of grill design may devise a number of alternative configurations that are similar and equivalent to the embodiments shown and described herein without departing from the spirit and scope of the claims.

Like reference numerals will be used to refer to like or similar parts from figure to figure in the following description of the drawings.

DETAILED DESCRIPTION OF THE DRAWINGS Referring first to Figures 1-4, an embodiment of an igniter 30 is shown. The igniter 30 is comprised of a body 31 into which an electrode 38 is inserted. The body 31 of the igniter is made from a ceramic, such as aluminum oxide (alumina) that has a purity of approximately 92%- 94% by weight, which is a readily available material. It is contemplated that other alternative materials could be used, such as materials which are non-conductive and are heat and corrosion resistant.

The body 31 includes an integrally cast gas collector (or hood) portion 32 and sleeve portion 34. The sleeve portion 34 is configured to mate with the apertures 45, 47 of the bracket 40, and includes a stop 36 which is configured to engage with the wing 44 to locate the electrode 38 above the orifices 22, 24. Although the sleeve portion 34 and the apertures 45, 47 as shown have a square cross section, it is contemplated that the sleeve 34 and apertures 45, 47 could comprise other shapes, such as round, square, or any other shape. The gas collector (or hood) portion 32 is positioned directly above the orifices 22, 24 of the burner 20 and includes a single, continuous, generally parabolic wall which at least partially encloses a volume. The gas collector (or hood) portion 32 captures the flammable gas and air thereby forming a combustible mixture for the igniter 30 and covers the electrode thereby protecting it from the elements (gas barbecue grills are intended to be ignited with the cover open; as such, the hood protects the electrode from wind and rain). It is contemplated that the gas collector 32 could comprise other shapes and/or additional walls. For example, the collector portion 32 could comprise a continuous curvilinear wall or multiple planar walls which form a box-like or other shaped gas collector. As better shown in Figures 3 and 4, the electrode 38 extends through the length of the sleeve portion 34 from a first end 33 of the sleeve portion 34 to a second end 35 of the sleeve portion 34. In one embodiment, the sleeve portion 34 of the igniter 30 has at least two desirable properties. First, it insulates the electrode to prevent sparks from occurring at undesirable locations. Second, because it is heat resistant, it will not melt due to the extreme heat that is generated by the burner 20. The first end 33 of the sleeve portion is sufficiently distanced from the heat source of the burner 20 whereby the electrode 38 can be connected to a lead wire 60 which is insulated with a material which has a lower melting temperature than the sleeve portion 34. Although not shown, it is intended that the lead wire 60 interconnect the electrode 38 with a device which is capable of creating an electric potential which is required to create a spark, such as a piezoelectric ignition device or other electric ignition devices.

At the second end 35 of the sleeve 34, the electrode 38 extends outside of the sleeve 34, whereby a tip 39 of the electrode 38 is disposed generally within a volume defined by the gas collector portion 32. The tip 39 is bent in the direction of the burner 20, thereby reducing the distance a spark must travel when the igniter 30 is activated. To facilitate a spark, it is intended that the electrode 38 be positioned approximately 3/16" (with a 1/32" tolerance) from the burner tube, although the device may still work if the spacing criteria is not met.

Referring now to Figure 1, a perspective view of a first embodiment of a gas burner igniter assembly 10 is provided. While the gas burner igniter assembly 10 is shown attached to a gas burner 20 of the type which is typically used for gas barbecue grills, it is contemplated that a person of ordinary skill in the art could easily configure the igniter assembly for use with other types of appliances, such as lamps, furnaces, cooktops, indoor and outdoor fireplaces or any other device which requires ignition of a flammable gas.

The particular burner 20 shown in Figure 1 (and 6) is an annular tube which includes a first set of orifices (or ports) 22 which are spaced apart along the length of the burner tube for distributing flammable gas along the length of the burner tube 20. The burner tube 20 includes a second set of orifices 24 near one end of the first set of orifices 22. The second set of orifices 24 are aligned transverse to the first set 22, whereby the orifices 24 are spaced apart around a portion of the circumference of the tube 20. The igniter assembly 10 is attached to the burner tube 20 near a first end of the burner tube 20, generally above the first and second set of orifices 22, 24. Two of the orifices from the first set of orifices 22 are directly below the hood 32 of the igniter 30 to provide sufficient combustible gas for ignition. Depending upon the orientation and size of the orifices, more or less orifices may be used. The second set of orifices 24 serve to provide a source of combustible gas for manual ignition, if required.

The igniter assembly 10 generally comprises an igniter 30, a bracket 40 and lead wires 60, 70. The bracket 40 serves to position the igniter 30 in close proximity to the orifices 22, 24 of the gas burner 20. The first embodiment of the bracket 40, as shown in Figures 1 and 2, has a first portion which engages with the igniter 30 and a second portion which engages with the burner tube. The first portion of the bracket 40 includes a first set of opposing wings 44, 46. Each of the wings 44, 46 includes an aperture 45, 47 which are aligned for receiving and holding the igniter 30 therein. The wing 46 is at a slight angle with respect to the other wing 44 and holds the igniter 30 is place by a friction fit. Although the wing 46 is tilted towards the wing 44, it is contemplated that the wing 44 could also be parallel with or titled away from the wing 46. The second portion of the bracket 40 comprises a second pair of wings 42a, 42b which are welded to the burner tube. The bracket 40 also includes a ground terminal 48 which is adapted to engage with a grounded lead wire 70. In the shown embodiment, the ground terminal 48 is a male ground terminal. While the ground terminal 48 depends from the wing 42a, it is contemplated that the ground terminal 48 could depend from any other portion of the bracket 40.

A second embodiment of the bracket 140 is shown in Figure 5. The second embodiment of the bracket 140, like the first embodiment 40, includes a first portion which engages with the burner tube 20, a second portion which engages with the igniter 30, and a ground terminal 148.

In contrast to the first embodiment of the burner tube, however, the second portion of the bracket 140 is not permanently attached to the burner tube 20 by welding. Instead, the first portion of the bracket 140 includes resilient gripping members or spring members 142a, 142b which grip the burner tube 20 and can be attached and removed from the burner tube without the use of tools. In that regard, the bracket 140 is suitable for use in retrofit applications to replace earlier- generation igniters and gas collector boxes which have deteriorated. The snap-fit connection 142a, 142b makes it simple for consumers to change out the deteriorated igniter assemblies. To install a new igniter 30 on an existing barbecue grill, the consumer simply snaps the bracket 140 into place on the burner tube 20, inserts the igniter 30 into the first portion of the bracket 140, and connects the lead wires 60, 70 to the igniter 30 and the bracket 140.

A third embodiment of a bracket 240 is shown in Figures 6 and 7. The third embodiment of the bracket 240 comprises two members 240a, 240b that can be disassembled to allow the burner tube and the first member 240a of the bracket 240 to be separately shipped from the supplier(s). As compared to the first embodiment, this configuration allows the burner tubes 20 to be more compactly boxed for shipment and prevents bending of the wings 244, 246 during shipping. The first member 240a of the bracket 240 engages with the igniter 30 and the second member 240b engages with the burner tube. The first member 240a includes a first set of opposing wings 244, 246, which are identical in nearly all respects to the wings 44, 46 of the first embodiment, and a ground terminal 248 which is adapted to engage with a grounded lead wire 70. The underside of the second member 240b is welded to the burner tube 20.

The first and second members 240a, 240b are configured for mating engagement. In the shown embodiment, the first and second members 240a, 240b are configured for sliding engagement. In particular, the second member 240b includes upturned wing members 242a, 242b which form slots for receiving corresponding wing members 243 a, 243b of the first member 240a. The first and second members 240a, 240b include locking members 245a, 245b which engage to firmly hold the first and second members 240a, 240b together. In the shown embodiment, the locking members 245 a, 245b provide a snap-fit. The locking member 245 a is an aperture (as shown) or recessed dimple (not shown) and the locking member 245b is a raised portion or raised dimple which is received by the locking member 245 a. The first member 240a includes a stop 247 which abuts the upturned wing member 243b when the first member 240a is properly positioned in mating engagement with the second member 240b.

In Figures 8-11, another embodiment of an igniter assembly 310 is shown which includes a fourth embodiment of a bracket 340. Figures 8-9 show the igniter assembly 310, along with e burner 120, in a barbecue grill firebowl 80. Figures 10-11 show close-up perspective views of the igniter assembly 310. As a means of improving assembly time and reducing the labor required to assemble the barbecue grill, the igniter assembly 310 is configured to be installed concurrently with the burner 120 in the firebox 80 of a barbecue grill.

In the shown embodiment, the burner 120 is a tube having a curvilinear, loop configuration, a series of orifices 122 oriented in an upward direction about the entire loop, and a series of three orifices 122a, 122b, 122c. The three orifices 122a, 122b, and 122c are aligned transverse to orifices 122 about a portion of the circumference of the burner 120. It is contemplated, that other sizes, types, and configurations of burners 120 can be used.

The firebowl 80 includes a mounting ledge 82 which extends into a socket 84 for holding and securing the burner 120 and igniter assembly 310. The mounting ledge 82 is configured to receive a common fastener (not shown), such as a nut and bolt, for securing the burner 120 and igniter assembly 310 in place. As shown, the mounting ledge includes an aperture 86, or through hole, for receiving the fastener and is provided with a recessed socket 88 on the underside of the aperture 86. The socket 88 has a shape which corresponds to a nut (not shown) whereby the socket 88 receives and holds the nut to prevent rotation thereof. The nut may be welded in the socket 88. Both the burner 120 and the bracket 340 include flange portions 124, 342, respectively. The flange portions 124, 342 each include apertures or slots 126, 344 that are configured to align with the aperture 86 in an assembled configuration. In the shown embodiment, the burner 120 has a slot to allow the assembler to adjust the position of the burner 120 relative to the igniter assembly 310. In the assembled position, the hood portion 32 of the igniter 30 is positioned generally above orifices 122a, 122b, 122c, which provide combustion gas to the igniter assembly 310. The hood portion 32 of the igniter extends outward from the bracket 340 to mitigate or prevent the flames from directly impinging upon the bracket 340. Like the previous embodiments, the bracket 340 includes a ground terminal 348. The ground terminal 348 of the fourth embodiment 340, however, is spring loaded to retain the igniter 30 in place.

The brackets 40, 140, 240, 340 are fabricated from a conductive material, such as sheet metal which is stamped and/or formed into shape. As discussed in more detail above, the brackets 40, 140, 240, 340 include push-on type ground terminals 48, 148, 248, 348 which are configured for attachment to a grounded lead wire 70 to ground the bracket. The connections between the burner 20, 120 and the bracket 40, 140, 240, 340 serve to pass the ground from the bracket to the burner 20, 120 . In this manner, when the igniter 30 is activated, a spark passes between the igniter 30 and the grounded burner 20 thereby igniting the flammable gas.

Although the inventions described and claimed herein have been described in considerable detail with reference to certain embodiments, one skilled in the art will appreciate that the inventions described and claimed herein can be practiced by other than those embodiments, which have been presented for purposes of illustration and not of limitation. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.

Indeed, it is expected that persons of ordinary skill in the art of grill design may devise a number of alternative configurations for the brackets and igniter that are similar and equivalent to the embodiments shown and described herein. For example, the brackets need not be formed from a conductive material. In such a case, the grounded lead wire could be directly connected to the burner tube. Also, the bracket need not be attached to the burner tube. It is contemplated that the bracket could be attached to other components, whereby the bracket could be configured to position the igniter in close proximity to the gas source. Even further, while the embodiments above describe the bracket and igniter as separate components, it is contemplated that the bracket and the igniter could be integrated into a single component. Even further yet, while the embodiments above describe the burner tube as being grounded whereby the ignition spark travels between the electrode and the burner, it is contemplated that a ground wire could also be embedded in the igniter body. In such a case, a portion of the ground wire (or an extension thereof, such as a plate) would be exposed near the wall of the collection portion of the igniter, whereby the ignition spark would travel between the wall of the collector portion and the electrode. Even further, while the embodiments of the ceramic igniter describe the sleeve portion and collector portion to be integrally cast, it is contemplated that the igniter need not be integrally cast. In fact, the sleeve portion and the collector portion need not be a single component.

Claims

I CLAIM:

1. A gas burner assembly comprising: a gas burner for providing a combustible gas through at least one port; an igniter comprising a body and an electrode, the body having a gas collector portion, the gas collector portion being configured to capture at least some of the combustible gas; an ignition device for generating a spark between the electrode and a ground; a bracket for positioning the gas collector portion of the igniter in close proximity to the at least one port; and, the body of the igniter being comprised of a non-conductive and heat and corrosion resistant material.

2. The gas burner assembly of claim 1 wherein the body further comprises a sleeve portion being integral with the collector portion and wherein the bracket holds the body at the sleeve portion.

3. The gas burner assembly of claim 2 wherein the bracket has at least one wing with an aperture and the sleeve portion has a stop, whereby the sleeve portion is adapted to mate with the aperture and the stop is adapted to engage with a periphery of the aperture to position the collector portion in close proximity to the at least one port of the burner.

4. The gas burner assembly of claim 1 wherein the gas collector portion has at least one wall which partially encloses a volume in which at least some of the combustible gas is captured.

5. The gas burner assembly of claim 1 wherein the body is comprised of aluminum oxide ceramic that has a purity of approximately 92-94% by weight.

6. The gas burner assembly of claim 1 wherein the bracket includes a connection, the connection being configured to allow the igniter to be attached to and removed from the gas burner by hand, without the use of tools.

7. The gas burner assembly of claim 6 wherein the connection allows the bracket to snap onto the gas burner.

8. The gas burner assembly of claim 1 wherein the bracket is connected to the gas burner by a welded connection.

9. The gas burner assembly of claim 1 wherein the gas burner is the ground.

10. The gas burner assembly of claim 9 wherein the bracket is attached to the gas burner and a grounded lead wire, whereby the bracket passes the ground to the burner.

11. The gas burner assembly of claim 1 wherein the ignition system is installed in barbecue grill and the gas burner is a burner tube having a plurality of ports along the length of the burner.

12. A gas burner assembly comprising: a gas burner for providing a combustible gas through at least one port; an igniter comprising a body and an electrode, the body having an insulating sleeve portion and a hood portion, the insulating portion being configured to prevent sparks at undesired locations, the hood portion being configured to capture at least some of the combustible gas, the insulating portion and the gas collector portion being integral, the sleeve portion having a first end and a second end, the hood portion depending from the second end of the sleeve portion, the electrode extending through the sleeve portion from the first end to the second end where the electrode extends outside of the sleeve portion into a partially enclosed volume defined by the hood portion; an ignition device for generating a spark between the electrode and a ground; a bracket for positioning the gas collector portion of the igniter in close proximity to the at least one port; and, the body of the igniter being comprised of a non-conductive and heat and corrosion resistant material.

13. The gas burner assembly of claim 12 wherein the collector portion of the body is comprised of a ceramic material.

14. The gas burner assembly of claim 12 wherein the bracket has a first portion for engaging with the igniter and a second portion for engaging with the gas burner.

15. The gas burner assembly of claim 12 wherein the gas burner and the bracket are mounted to a firebowl of a barbecue grill using a single fastener.

16. The gas burner assembly of claim 12 wherein the bracket comprises a first portion welded for holding the igniter and a second portion that is connected to the gas burner by a welded connection, whereby the first portion is configured to mate with the second portion.

17. The gas burner assembly of claim 12 wherein the gas burner is the ground.

18. The gas burner assembly of claim 12 wherein the bracket has at least one aperture for receiving the sleeve portion and the sleeve portion has a stop, whereby the stop is adapted to engage with a periphery of the aperture to position the hood portion in close proximity to the at least one port of the burner.

19. A gas burner assembly comprising: a gas burner for providing a combustible gas through at least one port; an electrode being disposed in close proximity to the port of the gas burner and a ground being in close proximity to the electrode; a hood portion being disposed at least partially above the electrode, the hood portion having at least one wall, the wall at least partially enclosing a volume for capturing at least some of the combustible gas; an ignition device for generating a spark between the electrode and the ground; and, the hood portion being comprised of a ceramic material.

20. A gas burner assembly for a barbecue grill comprising: a gas burner tube having a plurality of spaced apart ports for providing a combustible gas; an igniter comprising a body and an electrode, the body being comprised of a ceramic material and having an insulating sleeve portion and a hood portion, the insulating sleeve portion being configured to prevent sparks at undesired locations, the hood portion having at least one wall which at least partially encloses a volume, the insulating sleeve portion and the gas collector portion being integral, the insulating sleeve portion having a first end and a second end, the hood portion depending from the second end of the sleeve portion, the electrode extending through the insulating sleeve portion from the first end to the second end where the electrode extends outside of the sleeve portion at least partially into the volume; an ignition device for generating a spark between the electrode and a ground; a bracket for positioning the gas collector portion of the igniter in close proximity to the burner tube, the bracket having a first portion for engaging with the igniter and a second portion for supporting the bracket; and, a grounded lead wire being interconnected with the burner tube, whereby the burner tube is the ground.