Auto Reignition - Kitchen Appliances

Kitchen Appliances

Most gas ranges and cooktops use sparking devices to ignite the burner flame. This eliminates the need for a pilot flame, which wastes energy. Most of these sparking device-equipped ranges require the user to control the ignition sparking manually, resulting in a three-step process required to operate the burner:

1. turn burner knob to a position that opens the gas valve and activates the sparking (typically labeled "Lite")
2. wait for ignition, typically 0.5 to 2 seconds
3. turn burner knob past lite position, to stop the sparking noise and burning out the ignition electrode, to a desired flame intensity

One implementation of a gas burner with auto reignition senses the electrical conductivity of the flame. This nonzero flame conductivity is because combustion of natural gas releases enough free electrons to support a small current in air. An electronic circuit then starts or stops the igniter from sparking, based on whether the flame is lit. This reduces the number of steps to turn a burner on from three to one:

1. turn knob to a desired flame intensity—while confirming flame ignites

This is an elegant solution, compared to detecting flame via a thermocouple, a photoresistor or a mercury-filled sensor. No extra components or electrical connections between the sparker electrode and the spark module electronics are required.

This convenience and safety feature is found only (as of June 2009) on higher priced gas ranges and cooktops.