| 摘要 |
PROBLEM TO BE SOLVED: To reduce turn torque of a valve element by mounting a seat ring on an inner peripheral face of a valve main body with sufficiently large elastic tightening force to mount the seat ring stably. SOLUTION: This butterfly valve is constituted in such a way that the seat ring made of an elastic sealing material is mounted in the valve main body through which a cylindrical flow passage passes, the disc-like valve element coming into contact with the seat ring and leaving it is turnably supported, a valve rod shaft support part is formed in the direction of diameter of the valve main body to support a valve rod supporting the valve element, and an actuator is connected with an outer end of the valve rod on one side to drive and rotate the valve element. Compression allowance of the seat ring for the inner peripheral face of the valve main body is reduced in a central part of the seat ring and is increased in its both side parts. The seat ring is held on the inner peripheral face of the valve main body by elastic tightening force in both side parts to allow slight travel accompanying the valve element of the central part of the seat ring with which the valve element comes into pressure-contact and reduce movable torque of the valve element. COPYRIGHT: (C)2005,JPO&NCIPI
|
