Patent attributes
A valve for a line going to a subsurface safety valve can be blocked off with a valve that is initially held in a closed position. An upper spring pushes collets against a shoulder to keep a seal on a support assembly for the collets within an initial bore in a sealing relation. Application of pressure to the line urges the support assembly to move with respect to the collets and causes the collets to become unsupported. This initial movement of the support assembly is against a second spring that is weaker than the upper spring. The upper spring forces the collapsed collets into a smaller bore while the support assembly is retained against reverse movement at the urging of the second spring by a ratchet assembly. The seal is shifted into a bigger bore to allow flow through the valve and into or beyond the subsurface safety valve.
