(under subclass 39.821) Combustion devices wherein the ignition device comprises structure which either, (a) is capable of being made incandescent prior to and to produce initial combustion operation of the combustion device, or (b) is capable of being raised to and maintained for a sustained period of time in an incandescent state wherein the ignition device is raised to this state during an uninterrupted period of combustion of the combustion device.
(1) Note. A typical example of the type of ignition device provided for in (a) above would be an electrical filament through which an electrical current is passed causing the filament to become heated and incandescent. Similarly, a typical example of the type of ignition device provided for in (b) above would be a ceramic structure which upon being heated by combustion heat retains this heat for a very long time and therefore can be used to re-ignite a combustion device in which combustion has ceased.
