Dynamic slab gate valves

A slab gate valve comprising:

• a valve body formed with a through-bore in a first direction and formed with a gate cavity in a second direction orthogonal to the first direction;
• a slab gate having a first portion and a second portion, wherein the slab gate has a first side and a second side;
• wherein the gate cavity is sized and configured to receive the slab gate;
• wherein the first portion of the slab gate is sized and configured to occlude the through-bore when the slab gate is in a closed position;
• wherein the second portion of the slab gate is formed with a flow aperture for allowing flow therethrough when the slab gate is in an open position;
• at least one stem coupled to the slab gate for selectively moving the slab gate between the open position and the closed position;
• at least one seat cavity formed in the valve body proximate an intersection of the through-bore and the gate cavity;
• at least one dynamic seat assembly disposed in the at least one seat cavity;
• wherein the at least one dynamic seat assembly comprises:
• a cylindrical seat having a first side and a second side, wherein the first side of the cylindrical seat is adjacent the slab gate,
• a seat energizer disposed between the second side of the cylindrical seat and the valve body, and
• a seat seal disposed within a seat seal channel located proximate to a perimeter of the cylindrical seat, wherein the seat seal provides a seal between the cylindrical seat and the valve body, wherein the seat seal is a single solid elastomeric seal;
• wherein the first side of the cylindrical seat contacts the slab gate to form a metal to metal only seal to prevent or reduce fluid flow from the through-bore past the metal to metal only seal;
• a lower stem coupled to the slab gate and at least partially disposed within the gate cavity;
• a downstroke lubricant cavity formed in a portion of the valve body proximate to the gate cavity for containing a lubricant for lubricating the lower stem in a downstroke;
• at least one dynamic skirt assembly, disposed adjacent to the first side of the slab gate and disposed between the at least one seat cavity and the downstroke lubricant cavity, wherein a face of the at least one dynamic skirt assembly contacts the first side of the slab gate;
• and
• wherein the at least one dynamic skirt assembly at least partially prevents fluid flow between the downstroke lubricant cavity and the flow aperture of the second portion of the slab gate when the slab gate is in the closed position.