| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a butterfly valve in which valve body is precisely held at a closing posture while restraining opening/closing torque of a valve.SOLUTION: A butterfly valve has a seat ring 2 made of an elastic body, and a valve body 3 fitted with it. The valve body 3 rotates integrally with a valve shaft 7. A first protrusion 15 and a second protrusion 16 to hold an outer periphery of the valve body 3 under a closing posture from inside and outside are formed on an inner periphery of the seat ring 2. The first protrusion 15 and the second protrusion 16 are aligned in two lines in a circumferential direction, and the first protrusion 15 is positioned on a side of a flat receiving part 14. Even when there is no braking force in the valve shaft 7, rotation of the valva body 3 is blocked by the first protrusion 15 and the second protrusion 16. The first protrusion 15 is interrupted, and therefore, a burden on an actuator can be reduced by reducing torque required for opening/closing the valve body 3.</p> |
