Pressure energized gate valve seat and seal assembly

1. A gate valve, comprising:

a valve body having a gate cavity intersecting a channel having a proximal channel portion and a distal channel portion on opposing sides of the gate cavity, wherein a three-dimensional frame of reference comprises three mutually orthogonal directions, wherein an X axis corresponds to a center line of the channel, a Y axis is a center line of the gate cavity, and a Z axis orthogonal to the X axis and the Y axis;

a gate positioned in the gate cavity and moveable between a closed position blocking flow through the channel and an open position allowing flow through the channel, the gate having a proximal gate face and a distal gate face extending perpendicular to the channel; and

a proximal seat between a proximal valve body portion and the gate, the proximal seat having a first proximal seat face adjacent a proximal valve body face and a second proximal seat face adjacent the proximal gate face;

a proximal annular groove on a radial outer surface of the proximal seat;

a proximal axial seal positioned in the proximal annular groove in direct contact with the proximal seat and the valve body;

a proximal conduit extending through the proximal seat between the proximal channel portion and the proximal annular groove;

a distal seat between a distal valve body portion and the gate, the distal seat having a first distal seat face adjacent a distal valve body face and a second distal seat face adjacent the distal gate face;

a distal annular groove on a radial outer surface of the distal seat;

a distal axial seal positioned in the distal annular groove in direct contact with the distal seat and the valve body; and

a distal conduit extending through the distal seat between the distal channel portion and the distal annular groove.

2. The gate valve of claim 1 , wherein the proximal seat is a monolithic seat and the distal seat is a monolithic seat.

3. The gate valve of claim 1 , wherein the proximal seat simultaneously contacts the proximal valve body face and the proximal gate face during pressure conditions; and

the distal seat simultaneously contacts the distal valve body face and the distal gate face during pressure conditions.

4. The gate valve of claim 1 , wherein there is not a seal element positioned between the proximal valve body face and the first proximal seat face; and

there is not a seal element positioned between the proximal valve body face and the first proximal seat face.

5. The gate valve of claim 1 , wherein the proximal axial seal comprises a first proximal unidirectional seal and the distal axial seal comprises a first distal unidirectional seal.

6. The gate valve of claim 1 , wherein the proximal axial seal is a bi-directional seal assembly comprising a first proximal unidirectional seal with a first proximal hat ring and a second proximal unidirectional seal with a second proximal hat ring; and

the distal axial seal is a bi-directional seal assembly comprising a first distal unidirectional seal with a first distal hat ring and a second distal unidirectional seal with a second distal hat ring.

7. The gate valve of claim 1 , wherein the proximal axial seal is a bi-directional seal assembly comprising a first proximal unidirectional seal with a first proximal hat ring and a second proximal unidirectional seal with a second proximal hat ring;

a first passage through the first proximal hat ring between the proximal annular groove and the first proximal unidirectional seal;

a second passage through the second proximal hat ring between the proximal annular groove and the second proximal unidirectional seal;

the distal axial seal is a bi-directional seal assembly comprising a first distal unidirectional seal with a first distal hat ring and a second distal unidirectional seal with a second distal hat ring;

a first passage through the first distal hat ring between the distal annular groove and the first distal unidirectional seal; and

a second passage through the second distal hat ring between the distal annular groove and the second distal unidirectional seal.

8. The gate valve of claim 1 , wherein:

the proximal seat and the distal seat have a maximum ±0.001 inch thickness tolerance;

the gate has a maximum ±0.001 inch thickness tolerance; and

a seat pocket length from the proximal valve body face to the distal valve body face has a maximum ±0.002 inch thickness tolerance.