Abstract: A deep well pump for positioning in a bottom hole assembly and having at least one fluid pump and at least two fluid powered motors with the pump and motor pistons carried in alignment on the piston rod. The pump includes passages for delivering a power fluid to one end of each of the motor cylinders and for receiving exhaust fluid from the other end of the motor cylinders, and a valve for reversing this operation. A first sleeve is positioned around the first motor cylinder defining a power fluid path from one end of the first cylinder to one end of the second cylinder, a second sleeve is positioned around the first sleeve defining an exhaust fluid path from the other end of the first motor cylinder, and a third sleeve is positioned around the second motor cylinder defining an exhaust fluid path from the other end of the second motor cylinder, with the first and second exhaust fluid paths interconnected.

Abstract: A deep well pump for positioning in a bottom hole assembly and having at least one fluid pump and at least two fluid powered motors with the pump and motor pistons carried in alignment on the piston rod. The pump includes passages for delivering a power fluid to one end of each of the motor cylinders and for receiving exhaust fluid from the other end of the motor cylinders, and a valve for reversing this operation. A first sleeve is positioned around the first motor cylinder defining a power fluid path from one end of the first cylinder to one end of the second cylinder, a second sleeve is positioned around the first sleeve defining an exhaust fluid path from the other end of the first motor cylinder, and a third sleeve is positioned around the second motor cylinder defining an exhaust fluid path from the other end of the second motor cylinder, with the first and second exhaust fluid paths interconnected.

Abstract: A method and apparatus are provided for automatically and continuously balancing the unbalanced thrust resulting from the operation of a fluid pump which is driven by a fluid pressure motor. A hydrostatic-type thrust bearing is employed on the common shaft of the fluid pump and motor by applying pressures to opposite sides of the circular flange of such hydrostatic thrust bearing to compensate for any unbalance in thrust occuring during operation of the pump without requiring any axial movement of the hydrostatic thrust bearing flange. Because of the lack of flange movement, the thrust bearing operates with a constant fluid film thickness.