Metering device for introducing a liquid additive into a main liquid flowing along a pipe, includes a pump for withdrawing additive from a container and metering it, this pump including a first inlet for receiving a flow of main liquid which drives the pump, a second inlet for picking up additive and an outlet for the resulting mixture; a Venturi installed in the pipe, and connected in parallel with the pump, the first pump inlet connected by a first line to the Venturi inlet while the outlet connected by a second line to the Venturi throat; a first element for varying the restriction at the Venturi neck, and a second element sensitive to the pressure drop across the pump for controlling the first element to reduce the bore section when the pressure drop across the pump increases, and increase the bore section when the pressure drop across the pump decreases.

The temperature of a working medium is managed appropriately. A pressure intensifier includes a double-acting drive cylinder having first and second compartments separated by a piston driven by a working medium, high-pressure cylinders that discharge the fluid, a closed-circuit working medium pump that drives the pressure intensifier by sucking and discharging the working medium from and to the first and second compartments, first and second working medium channels, a collector that collects the working medium from the first and second working medium channels into a tank, and a low-pressure selector that selects, when the pressure of the working medium discharged toward the first or second compartment exceeds a predetermined threshold, the working medium discharged from the first or second compartment, and directs the selected working medium to the collector.

Methods and systems relate to a pressure exchanger which exchanges pressure energy from a high pressure clean fluid system to a relatively low pressure harsh fluid system for use in pressurizing the harsh fluid and directing the fluid to a wellbore as high pressure harsh fluid without the harsh fluid contacting identified portions of the pressure exchanger.

A pumping assembly includes a hydraulic pump having a hydraulic ram tied to a reciprocating annular piston having a central bore. When the annular piston moves in an upward direction, the hydraulic ram moves toward an extended position extending from the housing. When the annular piston moves in a downward direction, the hydraulic ram moves toward a retracted position retracted within the housing. A polish rod extends up through the central bore of the annular piston and is held in position by a polish rod clamp positioned on top of the hydraulic ram. The polish rod moves with the hydraulic ram. Other pumping systems, devices, and methods are also disclosed.

The present invention concerns a hydraulic pressure amplifier device comprising a casing (10) having two chambers (12, 14) of different cross-sections which house a staged piston (20) comprising two piston sections (22, 24) with cross-sections respectively el matching the chambers (12, 14), and means (30) for controlling the movement of the piston (20), characterised by the fact that the control means (30) are formed of an electronic control driven by means for estimating the ends-of-stroke of the piston (20) without an end-of-stroke sensor or mechanical stop.

A substance dispensing system that includes a hydraulic drive system is disclosed. The hydraulic drive system includes a hydraulic valve having a variable pressure setting, the hydraulic valve operable between a closed position in which a hydraulic pump moves hydraulic fluid to a hydraulic cylinder and an open position in which the hydraulic pump moves the hydraulic fluid to a hydraulic reservoir. The substance dispensing system of the present disclosure provides a system that recirculates hydraulic fluid in a hydraulic drive system instead of recirculating a substance back to a container via a pump. The substance dispensing system of the present disclosure allows for precise, accurate, and instantaneous control of an external force in a substance dispensing system.