| 摘要 |
<p>A butterfly valve comprising a valve body (2) a disk-shaped valve member (7) pivotally provided on the valve body (2), and a seat ring (1) fixed to the valve body (2), the seat ring (1) having a circumferential protrusion (3) on an inner surface thereof, said protrusion (3) having a sealing surface (10) to engage the valve member (7). In order to allow satisfactory closing of the valve the protrusion (3) has a greater width in a position (13) circumferentially remote from the rotation axis of the valve member (7) than adjacent that axis.</p> |
