| 摘要 |
<p>A subsurface safety valve has a resilient valve seat and an upwardly closing flapper plate whose sealing surfaces each have a match spherical radius of curvature. The sealing surface of the valve seat is a concave spherical segment of elastomer material and the sealing surface of the flapper plate is a convex spherical segment. The matching spherical surfaces are lapped together to provide a metal-to-metal seal along the interface between the nested convex and concave sealing surfaces. This permits angular displacement of the flapper plate relative to the valve seat without interrupting positive sealing engagement. The concave spherical seating surface of the resilient valve seat will tolerate a limited amount of misalignment of the flapper plate which may be caused by operation in low differential pressure, sandy well conditions.</p> |
