Patent ID: 8813848

Claim:
A down hole well isolation tool comprising a housing having a longitudinal passage therethrough, a first end and a second end; a first disc having a first side capable of withstanding a first pressure differential and a second side capable of withstanding a second pressure differential substantially greater than the first pressure, the second side of the first disc facing the first housing end; a second disc having a first side capable of withstanding a third pressure differential and a second side capable of withstanding a fourth pressure differential substantially greater than the third pressure differential, the second side of the second disc facing the second housing end; the first and second discs temporarily blocking flow through the longitudinal passage and comprising at least part of an enclosure resisting pressure applied from the first end of the housing and from the second end of the housing; the housing providing a passageway from adjacent the first end of the housing into the enclosure; and a gas generating assembly between the discs, fixed at a location between the discs prior to activation of the gas generating assembly, and an ignition train adapted to initiate the assembly upon a pressure command from adjacent the first end of the housing into the enclosure.