| 摘要 |
PROBLEM TO BE SOLVED: To provide a spherical valve eliminating its defect while making the most of a strong point of the spherical valve of which the center of the spherical valve body is decentered. SOLUTION: The spherical valve 10 is constituted of a valve drum 11, the spherical valve body 12 arranged in the inside of the valve drum 11, a normal seal 14 set on the downstream side of the valve drum 11 and a maintenance seal 13 set on the upstream side. A rotational center (p) of the spherical valve body 12 is decentered by a from a center P of the spherical valve body 12, the normal seal 14 is set with the center of the spherical valve body 12 as its standard and the maintenance seat 13 is set with the rotational center (p) of the spherical valve body 12 as its standard. It is devised to close the valve by pressing the normal valve against the spherical valve body 12 by adding hydraulic pressure from a back surface of the maintenance seal 13 at the time of replacing the normal seal 14, etc., and, during which, to carry out maintenance such as replacement of the normal seal 14, etc. COPYRIGHT: (C)2004,JPO
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