| 摘要 |
PCT No. PCT/JP97/00724 Sec. 371 Date Jul. 16, 1998 Sec. 102(e) Date Jul. 16, 1998 PCT Filed Mar. 7, 1997 PCT Pub. No. WO97/33110 PCT Pub. Date Sep. 12, 1997A safety valve of the type that includes a sleeve (1) with a high pressure port (11) and a low pressure port (12); a valve seat (2) and a poppet (3), both slidably inserted in the sleeve and adapted to be brought together to provide a valve interface that is capable of establishing and blocking a fluid communication between the high pressure port and the low pressure port; and a spring (7) adapted to force the poppet against the valve seat, wherein a difference in force between a fluid pressurized in the high pressure port acting on a pressure receiving surface of the poppet and the spring acting against said pressurized fluid urges the poppet to open the valve interface, thereby relieving the high pressure port by a portion of the pressurized fluid admitted out thereof into the low pressure port. The safety valve comprises a damper chamber (A) formed between the sleeve and the valve seat mentioned above, whose volume is reduced by a sliding movement of the valve seat against the action of the above mentioned spring; and a constriction adapted to bring the damper chamber into fluid communication with a low pressure side, the constriction (35) having an area of the fluid communication that is variable in such a way that it may be reduced by a sliding movement of the valve seat against the action of the spring and that it may be increased by a sliding movement in an opposite direction of the valve seat under the action of the spring.
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