Abstract: A fluid flow valve, the fluid flow valve having a body comprising a body inlet, a body outlet, and a housing; a movable member positioned within the housing and having a lower face, the movable member being movable between a position spaced from a position in said body when said valve is in an open position and movable to a sealing position when said valve is in a closed position; an elongated channel between the body inlet and the body outlet, wherein the channel has at least an essentially uniform internal diameter, with the exception of a raised seat therein, from the body inlet to the body outlet, and a raised seat positioned within the channel, wherein the lower face of the movable member is in the sealing position when positioned against the raised seat and a lip formed in the body.

Abstract: In a preferred embodiment, a dual contained purge connection for a dual containment valve, the valve having a body with inlet and outlet passageways and primary and secondary flow paths defined therein, the purge connection including: a purge fitting fixedly attached to the body and in communication with the primary flow path; and a housing having a closed distal end, surrounding the purge fitting, and having a proximal end removably attached to the body, an interior volume of the housing external to the purge fitting and surrounding the purge fitting being in communication with the secondary flow path.

Abstract: In a preferred embodiment, in a fluid flow valve having a body and having a movable member with lower face, the movable member being movable between a position spaced from a sealing position in the body when the valve is in an open position and movable to the sealing position when the valve is in a closed position, the improvement including: an annular sealing member disposed in the outer periphery of the lower face of the movable member to sealingly engage a portion of the body when the valve is in the closed position.

Abstract: In a preferred embodiment, in a fluid flow valve having a body and having a movable member with lower face, the movable member being movable between a position spaced from a sealing position in the body when the valve is in an open position and movable to the sealing position when the valve is in a closed position, the improvement including: an annular sealing member disposed in the outer periphery of the lower face of the movable member to sealingly engage a portion of the body when the valve is in the closed position.