Flapper valve with improved flapper

A flapper valve which comprises:

• a valve body which includes first and second ends, a flow bore which extends between the first and second ends, and an enlarged diameter cavity which intersects the flow bore;
• a valve seat which comprises a through bore that is aligned with the flow bore;
• a retainer which is positioned radially outwardly of the cavity;
• and
• a flapper which is pivotally connected to the retainer, the flapper comprising:
• a sealing side which is configured to engage the valve seat when the flapper is in a closed position;
• a core which is made of a rigid material, the core having a first side which corresponds to the sealing side of the flapper;
• a continuous circular stop ring which is connected to or formed integrally with the core on the sealing side of the flapper, the stop ring projecting outwardly from the first side of the core and being configured to engage the valve seat when the flapper is in the closed position;
• and
• a resilient coating which includes at least one of a radially inner portion that is disposed on the core radially inwardly of the stop ring and a radially outer portion that is disposed on the core radially outwardly of the stop ring, the at least one of the radially inner portion and the radially outer portion being configured to sealingly engage the valve seat when the flapper is in the closed position;
• wherein the stop ring and the at least one of the radially inner portion and the radially outer portion are configured such that, as the flapper moves into the closed position, the at least one of the radially inner portion and the radially outer portion will engage the valve seat before the stop ring engages the valve seat;
• whereby the stop ring limits the extent to which the at least one of the radially inner and the radially outer portion is compressed against the valve seat when the flapper is in the closed position.