MULTIPLE SPRING SUBSURFACE SAFETY VALVE

摘要

A subsurface safety valve features vertically stacked springs that are each independently supported in the valve housing and each having an opposite end that bears on a shoulder connected to the flow tube. When mounted this way their applied force is additive as they are in effect mounted in parallel between the housing and the flow tube for overcoming hydrostatic pressure in deep set applications that can exceed 20,000 feet. The stacking also allows the cross-sectional area of the flow tube to be maximized for a given housing outside diameter dictated by well conditions.