The Pow-R-Seal expanding gate valve uses a two-piece gate and segment assembly. In the fully closed position, the segment engages an end stop and the gate wedges downward, expanding the assembly to create a tight mechanical seal against both upstream and downstream seats.

During opening, the gate slides across the wedge angle of the segment, collapsing the assembly so it can travel freely between the seal faces. A lever-lock gate centralizer holds the mechanism in a neutral position until seal expansion is required.

When the segment bore aligns with the conduit bore, an end stop prevents further travel and the gate slides across the wedge angle, expanding the gate and segment to isolate flow from the valve body. A preferred flow direction helps ensure smoother operation and reduced operating torque.