| 摘要 |
PROBLEM TO BE SOLVED: To provide a relief valve capable of entering a full open state in a short time, without causing a change in valve opening pressure of respective times, even if valve opening-closing operation is performed over a plurality of times. SOLUTION: An annular seal member 13 for surrounding an opening part 11 is installed in the opening part 11 on the valve rod 5 side of a primary side port 8. A valve rod 5 is reciprocatably installed toward the annular seal member 13, and when the valve rod 5 is seated on the annular seal member 13, a seating position of the valve rod 5 is regulated so that the area of a first pressure receiving surface S1 becomes constant. Thus, this relief valve always opens under preset pressure. A second pressure receiving surface S2 is formed on the downstream side of the first pressure receiving surface S1 of the valve rod 5, and when the valve rod 5 separates from the annular seal member 13, fluid pressure of the primary side port 8 acts on the second pressure receiving surface S2. Thus, the valve rod 5 is displaced at once up to a valve opening position. COPYRIGHT: (C)2009,JPO&INPIT
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