PURPOSE: To detect abnormality in an equipment and change with time the lapse of by providing a sensor for detecting the physical property of a sealed liquid at a part where the sealing flow of a differential pressure transfer equipment is housed for monitoring the output of the sensor.
CONSTITUTION: When a small crack or a void occurs in liquid-contact diaphragms 114a and 114b of a differential pressure transfer equipment due to damage caused by corrosion etc., a process fluid penetrates or is diffused into a sealed flow 120 inside pressure-reception chambers 126a and 126b. Therefore, change in physical property occurs in the liquid 120 so that its specific dielectric constant also begins to change. At this time, the between parallel flat-plate capacitors of the physical property change detection sensors 150a and 150b provided inside the pressure reception chambers 126a and 126b simultaneously changes. The capacitance change is sent to a signal processing circuit 122 via insulation terminals 132 and 131 and is converted to electrical signal, thus allowing the differential pressure transfer equipment itself to detect that the diaphragms 114a and 114b are damaged or failed rapidly and also an upper- level instrumentation equipment controlling the differential pressure transfer equipment to detect it.
YAMAMOTO YOSHIKI
NAGASU AKIRA
KOBAYASHI TERUO
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