| 摘要 |
PURPOSE:To realize a stable detection of the oxygen content in the room air with a small erroneous action by inactivating the oxygen content detecting element for a predetermined period of time after starting the combustion and providing an converting element making the operation of the above oxygen content detecting element effective after lapse of a predetermined period of time. CONSTITUTION:A signal A of an ionic current of flame is compared with a basic voltage D in a voltage comparator 3. The result of the comparison is supplied to a signal F. Counting is started after a reset signal E is released by a timer 2 for setting a predetermined time (about 15min), and when the reset signal E is in a nonreleasing state and during the counting operation, a signal meaning nonoxygen-starvation is supplied to a signal B, and after the counting a signal meaning oxygen starvation is produced. If either one or both of the signal F and the signal B show an oxygen starvation state, the signal C becomes nonoxygen starvation. When both signal F and signal B become an oxygen starved state, the signal E is released simultaneously with the combustion starting. |
