| 摘要 |
PROBLEM TO BE SOLVED: To provide an eccentric butterfly valve capable of miniaturizing an actuator and the like, and reducing costs while securing high sealability. ! SOLUTION: A butterfly valve has a valve case 1 of which the inside has the circular shape, a disc-shaped valve element 2, and a valve shaft 3 penetrating through the valve case 1. The valve shaft 3 is inserted and fixed to boss portions 8, 9 projecting from the valve element 2. A valve seat 5 has a valve seat sheet 7 made of rubber. The valve shaft 3 is inclined by a proper angle θ2 to a Z-axis when observed from a Y-axis direction so that it is separated from the valve seat sheet 7 in accordance with approaching an actuator. In the final valve closing period, crushing action to the valve seat sheet 7 by the valve element 2 is advanced toward an upper part from a lower part, and in the initial valve opening period, separation of the valve element 2 from the valve seat sheet 7 is advanced toward the lower part from the upper part, so that the |
