| 摘要 |
PROBLEM TO BE SOLVED: To provide a pressure reducing valve capable of preventing leakage in the event of breakage of a pressure-displacement converting element such as diaphragm, piston or the like. SOLUTION: This pressure reducing valve comprises an air passing passage 28 communicating with the outside, which is provided within a spring chamber 16 water-tightly sealed by a pressure-displacement converting element 14 connected to a valve element 6 through a valve rod 23 and displaced by the pressure fluctuation of a secondary pressure chamber 4 and a spring cover 13 containing a regulating spring 15 for energizing the pressure-displacement converting element 14 to the opening direction of the valve element 6. Air is generally passed to the spring chamber 16 to prevent the fluctuation of the internal pressure of the spring chamber 16 by a temperature change. A means 30 for water-tightly blocking the air port 29 of the air passing passage 28 by the pressure water entered thereto from the secondary pressure chamber 4 through the spring chamber 16 in the breakage of the pressure-displacement converting element 14 is provided in the air passing passage 28, whereby the leakage is prevented.
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