Shearing gate valve

A shearing gate valve comprising

• a body having an inlet, an outlet, a valve chamber communicating with the inner ends of said inlet and said outlet, a recess surrounding the opening of each of said inlet and said outlet into said valve chamber,
• a seat ring positioned in each of said recesses within said valve chamber and having a bore therethrough to align with the inlet and outlet,
• a gate movably positioned within said valve chamber and having an opening therethrough which aligns with the bores of the mating seat rings to open and close flow through said body responsive to movement of the gate in said valve chamber,
• an insert sleeve positioned within said opening through the gate and having a bore which aligns with the mating bores in said seat rings,
• an actuator connected to said body and to said gate for moving said gate between its open and closed positions, and
• an insert ring positioned within one of said seat rings,
• said insert sleeve and said insert ring being of a hard, wear resistant material,
• said insert sleeve and said insert ring being installed and maintained in their respective positions in a compression preload condition which is sufficient to resist damage thereto during closing, sealing and shearing operations of the valve,
• said insert sleeve extends only partly through said gate opening,
• only one of said seat rings includes an insert ring to coact with said insert sleeve in shearing cables extending through said valve,
• said opening through said gate tapes to a larger opening on the side of the gate opposite to said insert sleeve,
• said seat ring on the side of the gate having a larger bore mating with the larger opening at the outlet of the gate and tapering to the smaller size of said outlet.