| 摘要 |
PROBLEM TO BE SOLVED: To provide a ball valve having an improved sealing property by a fluid pressure for maintaining the sealing property, suitably applicable to a low-temperature valve especially, reducing shrinkage in diameter of a ball seat, and preventing increase of valve operation torque when a low-temperature fluid is run to flow. SOLUTION: In this ball valve, a ball 14 having a through hole 14a is arranged freely rotationally inside a body 10 via annular ball seats 11 and 19. On the inside diameter side of the ball seat 11 arranged on a primary side, an action part 15 to be brought into contact with the ring type seat spring 12 is arranged, and a fulcrum 16 of the seat spring 12 is arranged on the inside diameter side of the ball seat 11 for reducing shrinkage in diameter of the ball seat 11. COPYRIGHT: (C)2004,JPO
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