| 摘要 |
<p>A valve assembly (10) including a body (16) defining a passageway (18) having a longitudinal axis (20), a rotatable shaft (22) extending into the passageway (18), generally perpendicular to the axis of the passageway (18), and a flapper (12) secured to the shaft (22) within the passageway (18) and movable upon rotation of the shaft (22) between an opened position and a closed position. The flapper (12) includes a groove (24) in an outer circumference (26), and a seal (14) is received in the groove (24). The seal (14) has an outer circumference (28) greater than the outer circumference (26) of the flapper (12) so the entire outer circumference (18) of the seal (14) contacts a wall (30) of the passageway (18) when the flapper (12) is moved to the closed position. The seal (14) also has an inner circumference (32) greater than an inner circumference (34) of the groove (24) of the flapper (12) such that an enclosed space (36) is defined between the seal (14) and the groove (24). An aperture (38) provides fluid communication between the enclosed space (36) and the passageway (18).</p> |
