| 摘要 |
<p>A ball type valve for high pressure lines is designed so that the spherical valve member is offset from the centerline of the valve stem in such a manner that the spherical valve member in the open position has a cylindrical fluid passage in parallel alignment with the flow axis of the inlet and outlet passages, but in the closed position is transversely disposed across the valve chamber so that the cylindrical flow passage is perpendicular to the flow axis of the inlet and outlet passages. Due to the eccentric placement of the valve stem onto the spherical valve member, and the eccentric placement of the bore of the bonnet in which the valve stem rotates relative to the centerline of the bonnet, and the eccentric placement of the bonnet opening relative to the centerline of the inlet and outlet passages, the spherical valve member rotates in an arc from open position to closed position so as to approach the valve seat tangentially with a wiping motion and at an angle of approach so that the spherical valve member is self-locking. Further, the design of the valve is such that in open position, the surface of the spherical valve member engages the wall of the valve chamber to prevent further rotation. This eliminates the need for an external stop and prevents rotation of the spherical valve member beyond the full open position.</p> |
