| 摘要 |
PURPOSE:To prevent accidents such as a fire and explosion, prevent inconveniences in using appliances and enhance safety, by turning OFF a main valve when a proportional control valve comes into an abnormal condition and the opening of the valve exceeds a predetermined range. CONSTITUTION:When the diaphragm 23 of the proportional control valve 5 is broken and a raw gas flows into a back pressure chamber 29, a valve opening detector 8 gives the abnormality signal to a discriminating circuit 15, a comparator 18 compares the signal with a value set on a setter 17, an an electric control circuit 13 turns OFF the main valve 1. Similarly, when a plate spring 26 is broken in a full-open combustion condition and a plunger 25 is locked by coming into contact with a solenoid 26, an operation deviated from a normal opening ranges is performed, so that the main valve 1 is turned OFF. Accordingly, accidents such as a fire and explosion and inconveniences in using appliances can be prevented, and safety can be enhanced. |
