Translating cavity valve

1. A valve assembly comprising:

a valve body;

an opening extending through the valve body along a longitudinal axis;

a valve member arranged within the opening, the valve member being movable, along the longitudinal axis, between an open position and a closed position;

an upper seal positioned within a top seal orifice formed in the valve member, the upper seal positioned to seal against at least a first portion of the valve body; and

a lower seal positioned within a bottom seal orifice formed in the valve member, the lower seal positioned to seal against at least a second portion of the valve body, wherein both the upper seal and the lower seal travel with the valve member as the valve member moves between the open position and the closed position, the upper seal and the lower seal defining a cavity that maintains a substantially constant value throughout movement of the valve member; and

a bypass ending through an axial length of the valve member, the bypass fluidly coupling a lower void and an upper void arranged at different ends of the opening.

2. The valve assembly of claim 1 , wherein the bypass is arranged within an outer diameter of the valve member, the bypass being fluidly isolated from a flow passage extending through the valve member.

3. A valve assembly comprising:

a valve body;

an opening extending through the valve body along a longitudinal axis;

a valve member arranged within the opening, the valve member being movable, along the longitudinal axis, between an open position and a closed position;

an upper seal positioned within a top seal orifice formed in the valve member, the upper seal positioned to seal against at least a first portion of the valve body; and

a lower seal positioned within a bottom seal orifice formed in the valve member, the lower seal positioned to seal against at least a second portion of the valve body, wherein both the upper seal and the lower seal travel with the valve member as the valve member moves between the open position and the closed position, the upper seal and the lower seal defining a cavity that maintains a substantially constant value throughout movement of the valve member; and

a seal integrity system, the seal integrity system obtaining a pressure reading for a volume between the upper seal and a stem packing, the seal integrity system identifying a leak in the upper seal when the pressure reading exceeds a threshold.

4. A valve assembly comprising:

a valve body;

an opening extending through the valve body along a longitudinal axis;

a valve member arranged within the opening, the valve member being movable, along the longitudinal axis, between an open position and a closed position;

an upper seal positioned within a top seal orifice formed in the valve member, the upper seal positioned to seal against at least a first portion of the valve body; and

a lower seal positioned within a bottom seal orifice formed in the valve member, the lower seal positioned to seal against at least a second portion of the valve body, wherein both the upper seal and the lower seal travel with the valve member as the valve member moves between the open position and the closed position, the upper seal and the lower seal defining a cavity that maintains a substantially constant value throughout movement of the valve member; and

a top bevel arranged axially higher than the upper seal, the top bevel having an upper slanted face extending radially outward from the longitudinal axis; and

a bottom bevel arranged axially lower than the lower seal, the bottom bevel having a lower slanted face extending radially outward from the longitudinal axis.

5. A valve assembly, comprising:

a valve body, the valve bodying having a flow bore extending along a flow bore axis;

an opening extending through the valve body along a longitudinal axis, the opening intersecting the flow bore;

a valve member positioned within the opening, the valve member being movable between an open position that aligns a flow passage with the flow bore and a closed position that aligns a block with the flow bore; and

a cavity defined by an upper seal of the valve member and a lower seal of the valve member, the cavity being translatable along the longitudinal axis in response to movement of the valve, the upper seal and lower seal each engaging the valve body to block fluid ingress into the opening, and

wherein a first sealing plane of the upper seal is non-intersecting with a valve seat.

6. The valve assembly of claim 5 , wherein a second sealing plane of the lower seal is non-intersecting with the valve seat.

7. A valve assembly, comprising:

a valve body, the valve bodying having a flow bore extending along a flow bore axis;

an opening extending through the valve body along a longitudinal axis, the opening intersecting the flow bore;

a valve member positioned within the opening, the valve member being movable between an open position that aligns a flow passage with the flow bore and a closed position that aligns a block with the flow bore; and

a cavity defined by an upper seal of the valve member and a lower seal of the valve member, the cavity being translatable along the longitudinal axis in response to movement of the valve, the upper seal and lower seal each engaging the valve body to block fluid ingress into the opening, and

a bypass ending through an axial length of the valve member, the bypass fluidly coupling a lower void and an upper void arranged at ends of the opening.

8. The valve assembly of claim 7 , wherein the bypass is arranged within an outer diameter of the valve member, the bypass being fluidly isolated from the flow passage.

9. A valve assembly, comprising:

a valve body, the valve bodying having a flow bore extending along a flow bore axis;

an opening extending through the valve body along a longitudinal axis, the opening intersecting the flow bore;

a valve member positioned within the opening, the valve member being movable between an open position that aligns a flow passage with the flow bore and a closed position that aligns a block with the flow bore; and

a cavity defined by an upper seal of the valve member and a lower seal of the valve member, the cavity being translatable along the longitudinal axis in response to movement of the valve, the upper seal and lower seal each engaging the valve body to block fluid ingress into the opening, and

a top bevel arranged axially higher than the upper seal, the top bevel having an upper slanted face extending radially outward from the longitudinal axis; and

a bottom bevel arranged axially lower than the lower seal, the bottom bevel having a lower slanted face extending radially outward from the longitudinal axis.

10. A valve assembly, comprising:

a valve body, the valve bodying having a flow bore extending along a flow bore axis;

an opening extending through the valve body along a longitudinal axis, the opening intersecting the flow bore;

a valve member positioned within the opening, the valve member being movable between an open position that aligns a flow passage with the flow bore and a closed position that aligns a block with the flow bore; and

a cavity defined by an upper seal of the valve member and a lower seal of the valve member, the cavity being translatable along the longitudinal axis in response to movement of the valve, the upper seal and lower seal each engaging the valve body to block fluid ingress into the opening, and

a seal integrity system, the seal integrity system obtaining a pressure reading for a volume between the upper seal and a stem packing, the seal integrity system identifying a leak in the upper seal when the pressure reading exceeds a threshold.