| 摘要 |
PURPOSE: A safety valve is provided to achieve a compactness in size of the valve with an improved operation. CONSTITUTION: A cylindrical first shutoff member(14) is pushed, by a pushing spring(21), at a first valve seat(11) of a main valve(5). A restricting passage(16) and a shutoff valve actuating chamber(17) are formed in sequence in a cylindrical hole(14a) of the first shutoff member(14). An interlocking wall(23) for interlocking with a predetermined length at a final point of time of the movement for shutting off the first shutoff member, is arranged between an inlet(P) and an outlet(R) in an inter space radially from the first valve seat. A valve-opening holding chamber(25) is formed by an interlocking portion(24) of the interlocking wall. Further, the shutoff valve actuating chamber is communicated to a second valve seat(31) of a pilot valve, thus allowing a second shutoff member(34) to contact the second valve seat by a pushing spring(37). The second valve seat(31) has a sealing sectional area(S) smaller than that(T) of the first valve seat, which in turn is smaller than a pressure sectional area(U) of the shutoff valve actuating chamber, and which in turn is smaller than a pressure sectional area(V) of the valve-opening holding chamber.
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