Abstract: A drive assembly for a progressive cavity pump includes a frame supported by the wel piping and a polish rod connected to the sucker rod. The polish rod is received by a rotary union formed by a sleeve portion rotatable with respect to a body portion with a seal structure that seals the sleeve and body portions during rotation. A mechanical drive, such as a hydraulic motor, electric motor or engine, has an output shaft that is linear with the polish rod and that has an axial passageway which receives the polish rod. A coupler mechanically couples an upper portion of the polish rod to the output shaft. The invention also includes a method of rotating a progressive cavity pump by this assembly.

Abstract: A pump having a reciprocating piston/plunger unit adapted to be actuated by a railway wheel rolling over it has a unitary plunger and piston, with the piston double-acting so that when the outlet pressure exceeds a certain value, the plunger remains retracted. An accumulator is provided in fluid communication with the outlet so as to store accumulated hydraulic pressure.

Abstract: Hydraulic cylinders made of fiber-resin composite materials have a central piston chamber section and bell-shaped internally threaded end sections. Cylinders are made by winding resin coated fibers over a mandril over which externally threaded sleeves are slipped and spaced apart so as to define the end sections. After curing the resin, the winding is cut in the areas of the sleeves to separate the cylinders. An expendable strip is wound onto the sleeves and in the cutting operation is cut into. A bearing, a seal cavity and an enlarged inside diameter at a piston rod end of the cylinder may also be provided using a method of the invention, with the cylinders being cut apart between the ends of sleeves and between the other ends of the cylinders.