Cartridge-type ball valve

A ball valve, comprising:

• a valve housing including a vertical side wall and a non-vertical end wall;
• a valve seat having a bottom wall parallel to the non-vertical end wall;
• a seal positioned between the bottom wall of the valve seat and the non-vertical end wall of the valve housing;
• a valve ball engaging the valve seat;
• and
• a central flow passage extending through the non-vertical end wall of the valve housing, the valve seat, and the valve ball;
• wherein at least a first section of each of the bottom wall of the valve seat and the non-vertical end wall of the valve housing are inclined toward the central flow passage at an angle of between about 20° and about 70° relative to the vertical side wall of the valve housing;
• wherein the seal is positioned between the first section of the bottom wall of the valve seat and the first section of the non-vertical end wall of the valve housing;
• wherein in a closed position the valve seat is configured to move relative to the valve housing a distance sufficient to cause the seal to disengage from the first non-vertical end wall of the valve housing and to provide an equalizing fluid passage between the valve seat and the valve housing in response to a fluid pressure.

A ball valve assembly, comprising:

• a first valve seat and a second valve seat, wherein each of the first valve seat and the second valve seats includes a vertical interior side wall and a bottom wall having a non-vertical section with a seal groove;
• a seal positioned in the seal groove in the non-vertical section of each of the first valve seat and the second valve seat;
• a valve ball sized to seal against the first valve seat and the second valve seat;
• a central flow passage extending through the first valve seat, the valve ball, and the second valve seat;
• wherein the non-vertical section of the bottom wall of the first valve seat is inclined toward the central flow passage at an angle of between about 20° and about 70° relative to the vertical interior side wall of the first valve seat.