Abstract: A pump jack system for vertically reciprocating a downhole pump in an oil and gas well. The pump jack system includes a cylinder assembly having a drive cylinder and two balance cylinders. A piston in the drive cylinder may be used to provide an upstroke of a sucker rod string of a downhole pump. The pistons in the balance cylinders may be used to provide a downstroke of the sucker rod string. Lower chambers in the balance cylinders counterbalance the lifting and lowering of the piston in the drive cylinder. The pump jack system also includes an accumulator for maintaining a relative constant fluid pressure in the lower chambers of the balance cylinders.

Abstract: A system and method to determine linear and approximate rotational position of a reciprocating and rotating hydraulic cylinder. The system uses two magnetic rings offset a distance, each ring having a continuous arc of magnetic material terminating in a blind zone, where the blind zone produces a magnetic field substantially different from the continuous arc region. The magnetic fields are used to detect location and rotation by an magnetic sensor that interacts with the magnets and blind zone.

Abstract: An apparatus and method for imparting an angularly rotational movement. The apparatus includes a cylinder having an internal portion, a rod operatively positioned within the internal portion of the cylinder, a first bearing operatively positioned about rod; a second unidirectional bearing operatively positioned about the rod and a motion program for selectively inputting incremental radial motion to the rod. The apparatus may also include a force generator for linearly moving the rod in a linear axial motion along an axis of the cylinder.

Abstract: A method of measuring a density of two liquid phases in a mixture with a gas phase. The three phase mixture is fed into an inlet vertical column of a flow loop where the gas phase is separated from a liquid mixture of the two liquid phases. The gas phase rises to an upper section of the inlet vertical column, while the liquid mixture flows to a lower section. A differential pressure of the liquid mixture is measured in the lower section. A density of the liquid mixture is calculated using the measured differential pressure of the liquid mixture. A volume or mass percentage is determined for each of the liquid phases in the liquid mixture. A volumetric flow rate is measured. A volumetric flow rate and accumulated volume of each liquid phase is calculated based on the volume or mass percentage of that liquid phase in the liquid mixture.