摘要 |
Disclosed is a butterfly valve having a seat, when viewed in cross-section, of generally U-shaped configuration, and an insert configured with appropriately shaped cooperating surfaces. The sealing effectiveness of the valve is enhanced by line pressure regardless of the direction of application of such pressure, the torque characteristics of the valve are relatively low, the ability to withstand temperature cycles is good, and the seat is restrained from destructive interference with the disc. |