| 摘要 |
A control system for fluid fuel burners, particularly for blue-flame oil burners, utilizes flame conduction to control energizing of the light emitting portion of an optical coupler. Circuit means including the light responsive portion of the optical coupler is effective, in the presence of a predetermined level of illumination from the light emitting portion which occurs in the absence of a burner flame, to enable flow of a combustible fuel-air mixture and energizing of ignition means, and, in the subsequent absence of the predetermined level of illumination when burner flame exists, to terminate energizing of the ignition means and to enable continued flow of the combustible mixture. The control system further includes means for reducing the rate and level of illumination of the light emitting portion so that it requires a predetermined time period for the light emitting portion to be energized to the predetermined level of illumination. This predetermined time period prevents initial energizing of the system in the event of a false flame indication, and enables uninterrupted system operation in the event of a momentary loss of flame conduction.
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