| 摘要 |
PURPOSE:To prevent a span from varying owing to the expansion and contraction of sealed liquid with temperature, static pressure, etc., by providing a bellows to a protection chamber which communicates with respective lead-in chambers, and pressing the top plate of the bellows against a housing with a specific force and producing differential pressure. CONSTITUTION:Lead-in chambers 3a and 3b are partitioned by seal diaphragm 10a and 10b into a lead-in side and a detection side, and a detection chamber 4 is partitioned by a pressure sensor 6 into two pressure reception sides. Further, bellows 7a and 7b having ceiling plates 9a and 9b are provided to protection chambers 5a and 5b and partitioned into an internal chamber side and an external chamber side. Then, the detection sides of the lead-in chambers 3a and 3b and the external chamber sides of the protection chambers 5a and 5b, and the external sides of the protection chambers 5a and 5b and the pressure reception side of the protection chamber 5a are linked mutually by communication paths 11a and 11b, and 12a and 12b. Then, pressure from the lead-in chambers 3a and 3b is applied to the bellows 7a and 7b and when the differential pressure exceeds specific pressure, the ceiling plates 9a and 9b move to open the openings of the communication paths 11a and 11b fully.
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