US Patent 7494107 Gate valve for plus-atmospheric pressure semiconductor process vessels

An isolation valve is preferably applied to the semiconductor industry for sealing a process vessel and also operates effectively at plus-atmospheric pressures. A double containment gate valve assembly includes a housing and a movable head assembly within the housing. The housing includes a first access opening and a second access opening. The head assembly is configurable into a first position where an access path through the first and second access openings is clear, and a second position where the access path is blocked.