| 摘要 |
PROBLEM TO BE SOLVED: To simplify a structure, surely carry out an operation so as to improve a handling performance by providing a thin film sensor wherein a conductive passage is drawn with a conductive material on a thin film surface capable of breaking when a safety valve is operated so as to specify a breaking position, and displaying an operation of the safety valve by opening of the conductive passage. SOLUTION: A thin film sensor 5 is formed into a nearly pentagonal shape, a thin film material 5a capable of easily breaking is stuck on all surface of the sensor 5, and the thin film material 5a has a such small strength that breaking pressure by a pressure difference between both surfaces of the thin film material 5a is not under the influence of a set pressure of a safety valve. A spread-eagle shaped conductive passage 12, terminals 14, and an annular breaking belt 13 which is crossed at nearly right angle with the conductive passage 12 and having an opening part 13a on a terminal, are displayed on a surface of the thin film material 5a. The safety valve is operated, gas is discharged, pressure acts on the thin film sensor 5 by pressure caused by leakage, the breaking belt 13 is broken, and the conductive passage 12 is opened. Only when a current is shut off by opening of an electric circuit, display is operated by means of lighting a lamp, transmission of an alarm, and the like in a safety valve operating display. Accordingly, the display is operated on the safety side at all times by fail safe function, and thereby, its reliability is improved.
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