SUBSURFACE WELL SAFETY VALVE WITH CURVED FLAPPER AND METHOD OF MAKING.

摘要

A subsurface well safety valve having a curved flapper closure member and method making. The curved flapper has a concave sealing surface coacting with a valve seat. A flow tube has a lower end contoured to the flapper sealing surface. A flapper can be made out of a tubular member in which the inside has been honed providing a flapper with a concave surface which forms a sealing surface.