Gaseous fuel burner and dual probe spark electrode therefor

A gaseous fuel burner having an annular base with a tubular inlet and enlarged diameter flange remote from the inlet deferring a cavity communicating with the inlet. A cap is registered against the flange rim to close the cavity and define a plurality of peripheral flame-generating ports. A pocket is formed in the periphery of the flange with an aperture formed in the pocket. A tubular ceramic igniter body with an enlarged flanged end is registered in the aperture. An elongated strip electrode is received through the igniter body in guideways; and, one end of the electrode is bifurcated and extends beyond the flange and is found at generally right angles to extend in spaced parallel arrangement with the face of the ignitor body flange for sparks discharge to the burner cap.

BACKGROUND OF THE INVENTION 
The present invention relates to fuel gas burners for cooking appliances 
and particularly burners of the type employed in cooktop or rangetop 
applications where a receptacle or cooking vessel is seated on the surface 
of the burner for heating of the foodstuffs or liquid within the vessel. 
Cooktop burners are typically ignited by the user opening a rotary valve 
in the supply line to provide a flow of the fuel gas to the burner 
whereupon a set of switch contacts are simultaneously closed for 
electrically energizing an igniter having an electrode disposed to provide 
a spark in the stream of fuel air mixture emanating from a port in the 
burner. If an alternating current voltage is employed for the spark 
ignitor, upon ignition of the fuel air mixture and the presence of flame 
about the ignitor electrode, the phenomenon of flame rectification occurs; 
and, the change in the current may be electrically detected as an 
indication or proof of the presence of flame. This technique has been 
widely employed for combining the function of the ignitor with that of a 
flame sensor and providing electrical circuitry which could respond to the 
change in alternating current to turn off the sparking voltage to the 
ignitor. It is also known to provide circuitry which, upon the loss of 
flame, electrically detects the change of a current in the electrode and 
reenergizes the ignitor spark voltage automatically. However, if transient 
air currents extinguish the flame about an annular plural port burner on 
only a portion of the periphery, the flame sensor may not be able to 
determine whether the flame has been totally extinguished and an annoying 
reenergization of the ignitor occurs. The condition may also occur where 
variations in the line pressure of the fuel gas cause major fluctuations 
in the flame. 
Thus, it has long been desired to provide a way or means of preventing 
flame loss in the region of the flame sensing ignitor when flame is being 
sustained in other regions of the burner and to generally stabilize the 
flow from the flame generating ports in the burner. It has further been 
desired to improve the effectiveness of a spark ignitor for a cooktop 
burner and to provide such functions in a burner which is sufficiently low 
in manufacturing cost to remain competitive in the high-volume domestic 
appliance marketplace. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a fuel gas burner for a 
cooktop having a spark ignitor disposed in a pocket formed adjacent 
certain flame-generating ports and to provide flame stabilization passages 
intermediate the flame-generating ports. 
It is a further object of the present invention to provide a spark ignitor 
assembly for a cooktop fuel gas burner with the ignitor assembly having a 
tubular refractory body with an electrode disposed therethrough with one 
end of the electrode bifurcated for providing dual sparking surfaces. 
It is a further object of the present invention to provide an ignitor 
assembly for a cooktop fuel gas burner, the ignitor having a tubular 
refractory body having a conductive electrode received therethrough with 
an air passage therethrough along the electrode. 
The cooktop burner of the present invention has a tubular inlet portion 
with an enlarged diameter portion formed at the remote end thereof and 
defining a fuel air mixture cavity which is closed by a burner cap along a 
parting line. An ignition pocket is formed in the periphery with a cut-out 
or aperture formed in the pocket with an ignitor received in the aperture. 
The ignitor has a tubular body of refractory material with an enlarged 
diameter flange formed at one end which is registered against the surface 
of the cut-out in the pocket. An elongated electrode is received through 
the tubular ignitor body with one end extending beyond the enlarged flange 
and bifurcated for providing dual sparking surfaces. In the preferred form 
the bifurcated end of the electrode is disposed at right angles to the 
direction of elongation.

DETAILED DESCRIPTION 
Referring to FIGS. 1-3, the assembly of the present invention is indicated 
generally at 10 and includes a base or body 12 which has a reduced 
diameter inlet portion defining an inlet 14 and an enlarged diameter 
flange portion 16 formed at the end thereof remote from the inlet and 
defining a fuel air mixture cavity 18 which is closed by a burner cap 20 
registered thereagainst. The parting line between the cap 20 and the base 
12 is formed with interdigitated portions which are preferably castellated 
as shown in the drawings but which may also be formed as sinusoidal or in 
a triangular toothed pattern. 
The alternate interdigitations or teeth denoted by reference numeral 22 
serve as registration surfaces for the cap 20 against the annular portion 
16 of the base 12 and define therebetween a plurality of primary 
flame-generating ports 24 which communicate with the plenum cavity 18. 
Referring to FIGS. 3 and 4, the base 12 is shown with the cap 20 removed 
and has an ignition pocket or recess 26 formed in the periphery thereof, 
which pocket has formed therein an independent ignition port which 
communicates the cavity 18 with the pocket 26. In the presently preferred 
practice the base 12 and cap 20 are formed of cast aluminum; and, to 
facilitate manufacturing, the ignition port is formed partially as a 
groove 29 in the cap and partially as a matching groove 28 in the base. 
Pocket 26 has an aperture 30 formed through the flange in the bottom of the 
pocket as shown in FIGS. 3 and 4. 
Referring to FIGS. 5 and 6, an ignitor assembly indicated generally at 32 
has a tubular body 34 formed of refractory or ceramic material and has an 
enlarged radially outwardly extending flange 36 formed at one end thereof. 
An elongated preferably flat strip conductive electrode 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 ignitor body. The bifurcated portions indicated by reference 
numerals 40,42 are formed externally of the flange 36 at generally right 
angles to the direction of elongation of the strip 38. The bifurcated 
portions 40,42 preferably extend in generally spaced parallel relationship 
to the end face of flange 36. 
Referring to FIG. 6, the inner periphery of the body 34 of the ignitor has 
a pair of oppositely disposed space parallel guide grooves or ways 44,46 
formed therein. The electrode "conductor" strip is held in place with a 
ceramic adhesive. The guide grooves 44,46 are configured to provide an air 
passage 47 about the electrode 38 through tubular body 34. 
Referring to FIG. 7, an alternative embodiment of the ignitor assembly is 
illustrated generally at 132 and has a tubular body 134 with an enlarged 
flange 136 at one end thereof with a generally flat conductive electrode 
strip 138 received therethrough with one end thereof 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 which extends in generally spaced parallel 
arrangement with the end face of flange 136. The arrangement of FIG. 7 
thus provides increased surface area on the electrode parallel to the 
undersurface of the burner cap 20 for spark discharge thereto from the 
electrode. The bifurcated end of the electrode 38,138 provides for 
additional separated areas of spark discharge on the undersurface of cap 
20 to thereby improve the reliability of the ignitor and increase the 
amount of spark area to ignite the fuel mixture emanating from the 
ignition port 28. The spark electrode design of the present invention also 
provides increased area of electrode to function as a flame-sensing probe 
after ignition, a function which is known in the art. The tubular form of 
the ignitor body 34 provides for secondary air to be drawn through the 
ignitor body passage 47 to aid in combustion of the flame in the pocket 26 
from the ignition port formed by grooves 28,29. 
Referring FIGS. 2, 3 and 5, recesses 50,52 are provided in the burner base 
on the radially inner surface of the wall of pocket 26 and disposed on 
opposite sides of the ignitor groove 28; and, corresponding projections 
54,56 extend downwardly from the undersurface of cap 20 and interdigitate 
with the recesses 50,52 to orient the ignitor groove 28 in the 
undersurface of the cap with the groove 28 formed in the base to form the 
ignitor port. The material between recesses 50,52 in the ignitor base 
serve to provide extra material radially inwardly of the burner pocket 
wall to extend the length of the groove 28; and, the corresponding port 
formed by closure of the cap thereover provides attenuation of pressure 
fluctuations through the ignitor port to thereby stabilize the ignitor 
flame. 
The present invention thus provides an improved gas burner having an 
annular base or body having a tubular inlet portion with an enlarged 
annular flanged end with a pocket formed in the periphery thereof with an 
ignitor received through an aperture in the pocket for spark discharge to 
the undersurface of a burner cap. The burner body flange defines a mixing 
cavity beneath the burner cap communicating with the inlet. The ignitor 
employs a tubular ceramic body with an enlarged diameter end flange having 
an elongated strip conductive electrode received in a pair of oppositely 
disposed parallel guideways formed within the ignitor body. One end of the 
electrode extends from an end of the ignitor body for electrical 
attachment thereto; whereas, the opposite end of the electrode extends 
through the ignitor body beyond the enlarged flange and is bifurcated and 
formed at generally right angles to the ignitor body to extend in spaced 
parallel relationship with the end face of the flange. The ignitor body is 
received in an aperture formed in the ignitor pocket. The ignitor 
construction provides an electrode having increased area for spark 
discharge and flame sensing. In one embodiment the bifurcated ends are 
open; and, in another embodiment are connected by a generally U-shaped 
member. 
Although the present invention has been described hereinabove with respect 
to the illustrated embodiments, it will be understood that the invention 
is capable of modification and variation and is limited only by the 
following claims.