| 摘要 |
PURPOSE:To prevent a drive mechanism from thermal effect by remote driving a valve body by the use of a pair of bellows to insulate thermally the drive mechanism from fluid in a path. CONSTITUTION:When a movable wall 6b of the drive side bellows 6 is lowered by operating a motor rotary actuator 9 in the required direction, the volume of inside space 6d in the bellows 6 is reduced to raise pressure of working fluid 7 in this space. Thus, the working fluid 7 in a fluid flow path 5 enters an inside space 4d of the driven side bellows 4 to extend this bellows so that a valve body 3 is moved in the closing direction. When the motor rotary actuator 9 is operated in the reverse direction, the driven side bellows 6 is contracted to move the valve body 3 in the opening direction. |
