Abstract: A swab is movably mounted within a well casing and automatically removes fluid from the well upon accumulated pressure at the bottom of the casing reaching a predetermined amount to raise the swab within the casing. The swab has a hollow body with an inner cylindrical bore. A control rod is slidably mounted within the bore and has a cross-sectional configuration whereby only a plurality of sliding contact lines occur between the rod and bore wall to reduce rod hangup and provide increased flow area between the rod and bore wall. A fluid inlet port is formed by an open bottom end of the swab body and is open and closed by a valve member located external of the swab body. The valve member has a generally pointed nose to reduce drag when the swab is descending into the casing, and upon contact of the nose with a stop at the bottom of the well casing, will automatically move to a closed position with the fluid inlet port.

Abstract: An interface tool freely slidable within a production pipe or conduit of an oil or gas well capable of creating a positive seal in order to lift liquids and particulates above the device to the surface where they are collected. An internal bypass valve permits the free flow of the particulates and liquids through an internal chamber of the tool during its return descent toward the producing formation. To efficiently utilize the pressure forces of gases trapped below the tool for lifting liquids to the surface when the bypass valve is closed, an elastomeric and expansible cylindrical sleeve is provided encircling a central region of the tool. Both the bypass valve and the elastomeric sleeve are operated by a slidable mechanical push rod received longitudinally within the tool body. The rod is actuated at extreme ends of the production pipe or conduit and detents provide for positive positioning of the rod during ascent and descent of the tool during well operation.