Patent ID: 7992840

Claim:
A gate valve, comprising: a valve body having a flow passage from a first port to a second port with a gate cavity disposed between the first port and the second port, the gate cavity intersecting the flow passage; a valve bonnet coupled to the valve body with a bonnet opening; a gate slidably coupled to the valve body in the gate cavity, the gate adapted to slidably move at an angle to a centerline of the flow passage to block the flow when the gate is in a closed position to cover a cross-sectional area of the flow passage and allow flow when the gate is at least in a partially open position when the gate does not entirely cover the cross-sectional area of the flow passage; a stem rotatably coupled through the bonnet opening to the gate and adapted to move the gate reciprocally across the cross-sectional area of the flow passage between the closed and open positions; a seat pocket disposed on each side of the gate cavity in the valve body, the seat pocket having a bore that forms an outer perimeter of the seat pocket and a back face in the valve body distal from the gate cavity to create a stepped surface around the flow passage; and a seat disposed in each seat pocket and adapted to seal between the gate and the valve body, comprising: a seat body having: a flow opening aligned with the flow passage; a gate face disposed toward the gate; a perimeter surface adapted to fit into the bore of the seat pocket; and a rear face disposed toward the back face of the seat pocket, the rear face having a shaped first metal radial sealing surface adapted to seal against the back face of the seat pocket in metal-to-metal contact.