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.