Abstract: A mud saver valve for insertion within the drill string to retain mud in the drill pipe and prevent the mud column from flowing past the valve when pumping is interrupted. The valve body has a tubular body and a piston having an axial passage for the flow of drilling mud. This piston is biased within the body by a spring and axially movable in response to the mud flow. A check valve plug is disposed within the bore which may be removed to run wireline tools. The plug is seated within a reduced diameter portion of the body and includes a replaceable inner sleeve which engages the piston to prevent flow through the valve. The inner sleeve is replaced as it becomes worn due to the erosive forces of the drilling mud.

Abstract: A mud saver valve for insertion within the drill string to retain mud in the drill pipe preventing the mud column from flowing past the valve when pumping is interrupted. The mud saver valve includes an internal check valve which permits increased flow of mud upward through the valve when a predetermined downhole pressure is reached. The increased flow of the check valve prevents a blow-out of the plug spear in the event sudden upward pressure is encountered. The check valve forms a part of the plug spear which is removable from the mud saver valve to facilitate the running of wireline tools.