Patent ID: 8434736

Claim:
A fluid passage valve comprising: a main body comprising a valve body which is disposed rotatably through a shaft, and a valve chamber in which the valve body is accommodated; a movable seat having a seating surface on which the valve body is seatable; and an elastic member for urging the movable seat in a direction opposite to the valve body, wherein: the valve body includes at least a spherical surface portion the shaft is installed on the valve body such that an axis thereof is disposed at a position offset from a center of curvature of the spherical surface portion, the movable seat includes a communication hole therein, an axis of which lies substantially perpendicularly to the axis of the shaft, the spherical surface portion of the valve body abuts against the seating surface thereby producing a valve-closed condition by closing the communication hole, and a valve-open condition is produced by separating the valve body from the movable seat and opening the communication hole.