Butterfly valve locking apparatus

A locking device for a valve of the type having a plate mounted in a flow conduit and movable between an open position wherein the plate allows passage of fluid material through the conduit from one side of the plate to the other side thereof, and a closed position wherein the plate blocks passage of fluid through said flow conduit, said conduit having an opening through which an actuating member extends and which includes a locking arm movable by said actuating member between an unlocking position wherein said locking arm is out of engagement with said plate and a locking position wherein said locking arm engages one side of said plate, said actuating member having a portion that extends externally of the conduit thereby allowing access to said actuating member by an operator, said conduit including a transverse bore and said actuating member comprising a shaft extending through said bore and externally thereof, said actuating member comprising a shaft having a longitudinal axis and a portion located internally of said conduit and being attached to said locking arm adjacent a portion of said locking arm so that rotation of said shaft about said longitudinal axis will effect rotation of said locking arm about said longitudinal axis between said unlocking position wherein said locking arm is out of contact with said plate and said locking position wherein said arm engages said plate to restrain movement of said plate.