US Patent 9291031 Isolation tool

A down hole pressure isolation tool is placed in a pipe string and includes a pair of pressure discs having one side that is highly resistant to applied pressure and one side that ruptures when much lower pressures are applied to it. The weak sides of the pressure discs face each other. Rather than rupturing the discs by dropping a go-devil into the well, a first of the discs is ruptured or broken by the application of fluid pressure from the well head or surface. Formation pressure is then used, in different ways according to the different embodiments, to rupture the remaining disc.