| 摘要 |
PURPOSE:To prevent incomplete combustion of fuel caused by the shortage of oxygen in a room or by other causes, by controlling a fuel control valve by use of an optical signal from an optical fiber which receives light produced by a red-heated body disposed at the top of the inner flame produced by a burner when it is heated by the inner flame. CONSTITUTION:A red-heated body 3 and an optical fiber 4 fixed to the body 3 are disposed at the top of inner flame 2 of the flame produced by a burner 1. One end of the optical fiber 4 is connected to a transistor 5 which converts an optical signal from the optical fiber 4 into a voltage signal, and the transistor 5 is in turn connected to a control unit 6 which controls a fuel control valve 7 in response to the voltage signal from the transistor 5. With such an arrangement, if the opening area of a primary-air port is reduced beyond the limit by some cause or other, the length of inner flame 2 is increased and its temperature is lowered. Resultantly, the intensity of light emitted from the body 3 is lowered, so that the control unit 6 is actuated by the optical fiber 4 and transistor 5 for closing the fuel control valve 7. Thus, it is enabled to prevent incomplete combustion of fuel in a reliable manner. |
