MXPA96001663A - Gaseous fuel burner and double probe electrode for the mi - Google Patents

Abstract

The present invention relates to a fuel gas burner assembly, comprising: a) an annular burner base having an inlet portion and an enlarged portion with a plurality of slits disposed around the periphery and a burner cap that closes said base and having a plurality of grooves forming primary flame generating gates with the grooves in said base; b) said base having a cavity formed in the periphery and one of said primary flame generating gates communicating with said and a cut-out of igniter formed in said cavity; c) a tubular insulator received in said cutout, said insulator of ceramic material, said insulator defined an air passage therethrough, and d) an electrode member disposed in said insulator and having an end portion. bifurcated that extends outward from one end of said insulator, where said insulator is received in said ingnitor cutout and said extr Electrode electrode fork is spaced adjacent to said cap for spark discharge between ell

Description

BURNER OF GASEOUS FUEL AND ELECTRODE OF SPARK OF DOUBLE PROBE FOR THE SAME BACKGROUND OF THE INVENTION The present invention relates to gaseous fuel burners for domestic kitchen appliances and particularly to burners of the type used in grill or stove applications where a receptacle or cooking vessel is seated on the surface of the burner to heat the food or liquids inside the container. The grill burners are typically ignited by the user opening a rotary valve in the supply line to provide a flow of combustible gas to the burner, upon which a set of contacts is simultaneously closed to electrically energize an ignitor having an electrode arranged to provide a spark in the stream of air and fuel mixture emanating from a gate in the burner. If an alternating current voltage is used for the spark ignitor, when ignition of the air and fuel mixture occurs and the presence of the flame around the ignitor electrode, the phenomenon of flame rectification occurs; and the change in the current can be detected electrically as an indication or proof of the presence of the flame. This technique has been widely used to combine the function of the ignitor or igniter with that of a flame sensor and provide electrical circuits that can respond to the change in alternating current to eliminate the spark voltage to the ignitor. It is also known to provide circuits which, when flame loss occurs, electrically detect the change of a current in the electrode and re-energize the spark voltage of the ignitor automatically. However, if transient air currents extinguish the flame around a burner of several annular gates over only a portion of the periphery, the flame sensor may not be able to determine if the flame has been completely extinguished and an annoying -energization of the ignitor. The condition can also occur where variations in the line pressure of the fuel gas cause greater fluctuations in the flame. In this way, for so long it has been desired to provide means or a way to prevent the loss of flame in the region of the igniter flame sensor when the flame is being held in other regions of the burner and to generally stabilize the flow of the generating gates. of flame in the burner. It has been further desired to improve the effectiveness of a flame igniter for a grate burner and to provide such functions in a burner that is of sufficiently low manufacturing cost to be competitive in the high volume market of household appliances. SUMMARY OF THE INVENTION It is an object of the present invention to provide a fuel gas burner for a grate having a spark igniter disposed in a cavity formed adjacent to certain flame generating gates and providing flame stabilization passages between the gas generating gates. call. It is a further object of the present invention to provide a spark igniter assembly for a grate fuel gas burner with the ignitor assembly having a tubular refractory body with an electrode disposed therethrough, one end of the bifurcated electrode to provide double forming surfaces of spark. It is a further object of the present invention to provide an ignitor assembly for a grate fuel gas burner, the igniter having a tubular refractory body having a tubular electrode received therethrough with an air passage therethrough along the electrode . The grate burner of the present invention has a tubular inlet portion with an enlarged diameter portion formed at its remote end and defining a fuel and air mixture cavity that is closed by a burner cap along a line of division. An ignition cavity is formed in the periphery with a cutout or opening formed in the cavity, with an ignitor received at the opening. The ignitor has a tubular body of refractory material with a flange of enlarged diameter formed at one end which registers against the surface of the cutout in the cavity. An elongate electrode is received through the tubing igniter body, one end extending beyond the pleasing and bifurcated flange to provide double spark formation surfaces. In the preferred form, the bifurcated end of the electrode is disposed at right angles to the direction of elongation. Brief Description of the Drawings Figure 1 is a cross-section of the grate burner of the present invention in the assembled condition. Figure 2 is an enlarged sectional view taken along the indicator lines of section 2-2 of Figure 1. Figure 3 is an axonometric view of the burner base of the embodiment of Figure 1. Figure 4 is an enlarged view of a portion of Figure 3 seen from the rear. Figure 5 is an enlarged portion of a left end view of the embodiment of Figure 1. Figure 6 is an axonometric view of the igniter assembly of the embodiment of Figure 1. Figure 7 is a similar view. to figure 6 of another embodiment of the igniter. Detailed Description Referring to Figures 1-3, the assembly of the present invention is generally indicated at 10 and includes a base or body 12 having a reduced diameter inlet portion defining an inlet 14 and a flange portion of diameter enlarged 16 formed at its remote end of the inlet and defining a fuel and air mixture cavity 18 which is closed by a burner cap 20 registered against it. The dividing line between the lid 20 and the base 12 is formed with interdigitated portions which are preferably crenellated, as shown in the drawings, but which may also be formed in a triangular or sinusoidal toothed pattern. The alternate interdigitations or teeth denoted by the reference number 22 serve as registration surfaces for the cover 20 against the annular portion 16 of the base 12 and define between them a plurality of primary flame generating gates 24 communicating with the cavity full 18. With reference to figures 3 and 4, the base 12 is shown with the lid 20 removed and has an ignition recess or cavity 26 formed in its periphery, said cavity having formed therein an independent ignition gate that communicates the cavity 18 with the cavity 26. In presently preferred practice, the base 12 and the cap 20 are formed of formed aluminum; and, to facilitate manufacturing, the ignition gate is partially formed as a slot 29 in the lid and partially as a slot 28 even in the base.The cavity 26 has an opening 30 formed through the flange at the bottom of the cavity, as shown in Figures 3 and 4. With reference to Figures 5 and 6, an ignitor assembly generally indicated at 32 has a body tubular 34 formed of refractory or ceramic material and has a radially outward, enlarged flange 36 formed at one of its ends. An elongated conductive electrode, preferably a flat strip 38, is received therethrough and extends outwardly from the lower end of the tubular body 34 for external electrical connection thereto. The opposite end of the electrode 38 is bifurcated and extends outwardly through the flanged end of the igniter body. The bifurcated portions indicated by the reference numerals 40, 42 are formed externally of the flange 36 at a right angle generally with the direction of elongation of the strip 38. The bifurcated portions 40, 42 preferably extend in parallel relation generally spaced with the end face of the flange 36. Referring to Figure 6, the internal periphery of the body 34 of the ignitor has a pair of parallel slots or guides, arranged opposite, 44, 46 formed therein. The "conductive" strip of the electrode is held in place with a ceramic adhesive. The guide slots 44, 46 are configured to provide an air passage 47 around the electrode 38 through the tubular body 34.

Referring to Figure 7, an alternative embodiment of the ignitor assembly is generally illustrated at 132 and has a tubular body 134 with an enlarged flange 136 at one end thereof with a generally flat electrode conductive strip 138 received therethrough. , one of its ends extending outwardly from flange 136 and bifurcated as indicated by reference numerals 140, 142. The bifurcated portions 140, 142 are interconnected by a generally U-shaped bar portion 143 extending in arrangement parallel, generally spaced with the end face of the flange 136. The arrangement of FIG. 7 in this manner provides increased surface area to the bottom surface of the burner cap 20 for spark discharge thereto from the electrode. The bifurcated end of the electrode 38, 138 provides additional sparking areas on the bottom surface of the cap 20 to thereby improve the reliability of the igniter and increase the amount of spark area to ignite the fuel mixture emanating from the igniter. of the ignition gate 28. The spark electrode design of the present invention also provides increased electrode area to function as a flame sensing probe after ignition, a function that is known in the art. The tubular shape of the igniter body 34 allows secondary air to be drawn through the passage 47 of the igniter body to assist in combustion of the flame in the cavity 26 from the ignition gate formed by the slots 28, 29. Referring to FIG. to Figures 2, 3 and 5, the recesses 50, 52 are provided in the base of the burner on the radially internal surface of the wall of the cavity 26 and arranged on opposite sides of the igniter slot 28; and corresponding projections 54, 56 extend downwardly from the bottom surface of the cap 20 and interdigitate with the recesses 50, 52 to orient the igniter slot 28 on the bottom surface of the cap with the slot 28 formed in the base to form the ignitor gate. The material between the recesses 50, 52 at the base of the igniter serves to provide additional material radially inwardly of the wall of the burner cavity to extend the length of the slot 28; and the corresponding gate formed by closing the lid on it provides attenuation of pressure fluctuations through the ignitor gate to thereby stabilize the flame of the igniter. The present invention in this manner provides an improved gas burner having an annular body or base having a tubular inlet portion with an annular end., enlarged with flange, with a cavity formed in its periphery with an ignitor received through an opening in the cavity for spark discharge to the lower surface of a burner cap. The flange of the burner body defines a mixing cavity below the burner cap which communicates with the inlet. The igniter employs a ceramic tubular body with an enlarged diameter end flange having an elongated conductive strip electrode received in a pair of opposingly arranged parallel guides formed within the igniter body. One end of the electrode extends from one end of the ignitor body for electrical connection to the same; while the opposite end of the electrode extends through the body of the ignitor beyond the enlarged flange and bifurcates and forms generally at right angles to the body of the ignitor to extend in parallel spaced relationship with the end face of the flange. The body of the igniter is received in an opening formed in the cavity of the igniter. The construction of the igniter provides an electrode that has an increased area for spark discharge and flame detection. In one embodiment, the bifurcated ends are open, and in another embodiment, they are connected by a generally U-shaped member. Although the present invention has been described above with respect to the illustrated embodiments, it will be understood that the invention is capable of modifications and variations and is only limited by the following claims.

Claims (22)

1. CLAIMS 1. A fuel gas burner assembly, comprising: (a) an annular burner base having an inlet portion and an enlarged portion with a plurality of primary flame generating gates disposed around the periphery and a cover burner that closes said base; (b) said base having a cavity formed in the periphery and a flame generating ignition gate communicating with said cavity and an ignitor cutout formed in said cavity; (c) a tubular insulator received in said cut-out, said insulator formed of ceramic material, said insulator defining a passage of air therethrough; and (d) an electrode member disposed in said insulator and having a bifurcated end portion extending outward from one end of said insulator, wherein said insulator is received in said igniter cutout and said bifurcated electrode end is disposed spaced adjacent to said cap for spark discharge between them. The assembly defined in claim 1, wherein said insulator has a flange of enlarged diameter formed at said end, said flange registered against said base about said cutout. The assembly defined in claim 1, wherein said electrode extends outwardly from said insulator from an end remote from said end and is adapted for electrical connection thereto. The assembly defined in claim 1, wherein said electrode is formed of an elongate strip having said bifurcated end formed generally at right angles to the direction of elongation of said strip. The assembly defined in claim 1, wherein said insulator has a radially outwardly extending flange formed at one of its ends, and said bifurcated end of said electrode extends in parallel, generally spaced relationship with said flange. The assembly defined in claim 1, wherein said insulator has a radially outwardly extending flange formed integrally at said end. The assembly defined in claim 1, wherein said cavity has a pair of opposingly arranged walls in a generally divergent array. The assembly defined in claim 1, wherein said base includes a transfer passage communicating said cavity with one of said primary gates. The assembly defined in claim 1, wherein said ignition gate is partially formed in said base with the rest formed in said cover. 10. The assembly defined in claim 1, wherein said base includes a transfer passage that communicates between certain adjacent primary gates. The assembly defined in claim 1, wherein said base entry portion includes means defining a vacuum cleaner. The assembly defined in claim 1, wherein said cutout comprises an opening formed axially in a radially extending portion of said enlarged portion. 13. The assembly defined in claim 1, wherein said electrode is disposed in said air passage. A method of making a fuel gas burner assembly, comprising: (a) forming a burner base having a tubular portion defining an inlet and an enlarged annular portion forming a cavity communicating with said inlet and forming a plurality of flame generating gates around it that communicate with said cavity; (b) arranging a lid over said cavity of the enlarged portion; (c) forming a cavity in said enlarged portion and forming an opening in said cavity adjacent to one of said gates; (d) forming a tubular insulator and arranging it in said opening; and (e) bifurcating one end of a strip of conductive material and inserting said strip into said insulator and spacing said bifurcated end for spark discharge to said cap. 15. The method defined in claim 14, wherein said step of arranging an insulator includes forming a flange extending radially outwardly at one end of said insulator and registering said flange against said base about said opening. The method defined in claim 14, wherein said bifurcating step includes forming the bifurcated end at right angles to the strip. 17. A fuel gas burner assembly, comprising: (a) a base having a tubular inlet portion with a radially outwardly extending flange formed at one of its ends, said flange having a ring formed around its periphery; (b) a cap registered against said ring and cooperating with said ring to define a plurality of primary flame generating gates; (c) said ring having a cavity formed in its periphery with an igniting flame generating gate therein, said cavity having a cutout formed in said flange; (d) a tubular fastener formed of refractory material received in said cutout, and (e) an elongated electrode strip having a bifurcated end formed generally at right angles to the direction of elongation received in said fastener, said bifurcated end disposed for spark discharge to said lid. 18. The burner assembly defined in claim 17, wherein said tubular fastener has a pair of guided surfaces disposed therein in parallel arrangement, generally spaced, with said electrode slidably linked by said guide surfaces. 19. The burner assembly defined in claim 17, wherein said tubular fastener has a radially outwardly extending flange formed at its end adjacent said bifurcated end of said electrode. 20. A spark ignitor assembly, comprising: (a) a tubular body member formed of refractory material and having a radially outwardly extending flange formed at one of its ends, and (b) an elongated electrode formed of electrically conductive material disposed within said tubular member and extending outwardly from one end of said member adapted for electrical connection thereto, the end remote from said end being bifurcated and extending outward from said flanged end of said body member, said tubular member defining an air passage therethrough along said electrode. 21. The igniter assembly defined in claim 20, wherein said bifurcated end of said electrode extends generally at right angles to the direction of elongation. 22. The ignitor assembly defined in claim 20, wherein said body member includes therein formed a pair of generally parallel, spaced, oppositely disposed guide surfaces with said electrode slidably received therein.