Flapper check valve assembly

A valve system, comprising:

• a body defining an inner volume and a wall that surrounds the inner volume;
• a swing assembly disposed inside the inner volume, the swing assembly comprising:
• a disc movable between an open position and a closed position;
• and
• an arm connected to the disc;
• and
• a key assembly positioned on an exterior surface of the body, the key assembly comprising:
• a hollow hub with a body and a keyway, wherein the keyway is formed as a cutout on an inner surface of the hollow hub;
• and
• a shaft concentric with the hollow hub, the shaft including a body and a keyseat, wherein the keyseat is formed as a cutout on an outer surface of the shaft;
• wherein the shaft of the key assembly extends through the wall and detachably connects to the arm of the swing assembly.

A swing check valve, comprising:

• a body defining an inner volume and a wall that surrounds the inner volume, the inner volume having a generally cylindrical flow path, and a disc receiving recess;
• and
• a swing assembly disposed inside the inner volume, the swing assembly comprising a disc, wherein:
• the disc is movable between:
• (1) a closed position in which the disc is positioned substantially within the cylindrical flow path;
• and (2) an open position in which the disc is entirely received in the disc receiving recess;
• and
• the disc includes a protrusion that extends furthest at a radial center portion of the disc, and in the closed position, a furthest extent of the protrusion of the disc being flush with a generally cylindrical outer extent of the generally cylindrical flow path.