Waterwell pump assembly

A pump assembly adapted to be supported at a selected pumping level within a tubular well casing and effective to repeatedly withdraw quantities of liquid and gas from said casing and discharge the same at ground level, said pump assembly comprising an elongated vertically disposed cylinder having a circular bottom wall provided with a central inlet port for the admission of gas and liquid upwardly into the cylinder, a unidirectional foot valve normally seated upon said port and closing the same, said foot valve being responsive to differential fluid pressure on opposite sides of said bottom wall and being effective to admit gas and liquid upwardly through said port when fluid pressure beneath said bottom wall exceeds the fluid pressure within the cylinder, a pump shaft reciprocal vertically within said cylinder and coaxial therewith, a combined plunger and traveling valve assembly within said cylinder and including an inverted cup-shaped plunger having a top wall fixedly secured to the lower end of said pump shaft and a depending cylindrical side wall provided with circumferentially spaced ports therethrough, a tubular clamping nipple threadedly received within the lower rim region of said side wall, an elastomeric sealing ring interposed between said nipple and the lower rim of said plunger and establishing a lip seal with the cylinder, and a lift valve normally closing the upper end of said tubular nipple, said lift valve being responsive to pressure of fluid beneath said plunger during the downstroke of the latter to bypass such fluid upwardly through said nipple and plunger, and being responsive to pressure of fluid above said plunger to prevent such upward passage of fluid, the upper end of said cylinder being formed with an enlarged diameter extension which establishes a valve housing, the juncture region between said cylinder and extension providing an annular ledge which establishes a valve seat, a floating head valve member disposed within said valve housing and encompassing said pump shaft, said head valve member including an annular disk-like valve body and an upstanding cylindrical wall concentric with the pump shaft, a packing gland disposed within said cylindrical wall and effective between the pump shaft and wall, a gland nut threadedly received in the upper end of said cylindrical wall, an elastomeric sealing ring mounted on the underneath side of said disk-like valve body and normally seated on said valve seat, a cylindrical drop tube encompassing said pump shaft and having its lower end threadedly received in the upper end of said cylindrical wall, and a compression spring interposed between the lower end of said drop tube and disklike valve body exteriorly of the cylindrical wall and serving to yieldingly bias said valve member against said valve seat.