US Patent 7533693 Side-mounted position indicator for flapper check valve

The present invention is a side-mounted position indicator for use with a flapper check valve. The indicator is located outside the valve body and attaches to an internal, cylindrically-shaped roller that allows limited rotation about one axis. This roller has a tripper rod that extends from one side of the roller and has a round, non-marring plastic ball on its opposite end. The ball is held in contact with the valve flapper using a mechanical spring. A separate flush port is provided to allow for periodic internal cleaning without substantial disassembly.