A lift apparatus and method for driving a downhole reciprocating pump is disclosed. The apparatus includes a hydraulic cylinder having a piston and a hydraulic fluid port, the piston being coupled to a rod for driving the reciprocating pump, the piston being moveable between first and second ends of the cylinder in response to a flow of hydraulic fluid through the hydraulic fluid port. The apparatus also includes a variable displacement hydraulic pump coupled to receive a substantially constant rotational drive from a prime mover for operating the hydraulic pump, the hydraulic pump having an outlet and being responsive to a displacement control signal to draw hydraulic fluid from a reservoir and to produce a controlled flow of hydraulic fluid at the outlet. The apparatus also includes a hydraulic fluid line connected to deliver hydraulic fluid from the outlet of the hydraulic pump through the hydraulic fluid port to the cylinder for causing the piston to move through an upstroke away from the first end and toward the second end of the cylinder. The apparatus further includes a valve connected between the hydraulic fluid port and the reservoir, the valve being responsive to a valve control signal for controlling discharge of hydraulic fluid from the hydraulic fluid port of the cylinder back to the reservoir to facilitate movement of the piston through a downstroke away from the second end toward the first end of the cylinder. The valve is operable to prevent flow of hydraulic fluid through the valve during the upstroke and the hydraulic pump is operable to prevent flow of hydraulic fluid back into the outlet of the hydraulic pump during the downstroke.

A lease automatic custody transfer (LACT) system includes a pump assembly and meter system. The pump assembly is configured to pump a volume of fluid out of a storage container into a conduit. The pump assembly causes a pulsating flow of the volume of fluid through the conduit. The meter system is coupled to the conduit and includes a meter device and a processing system. The meter device is configured to obtain a plurality of measurements corresponding to the volume of fluid flowing through the conduit. The processing system is communicatively coupled to the meter device and configured to determine a flow parameter value based on the plurality of measurements.

The invention relates to a multi-chamber with ultra-high-pressure or hydraulic motor compressors or motor pumps for compressing gas or liquid at ultra-high pressure, formed by several different-sized concentric chambers, wherein each chamber contains smaller chambers, there being installed between the chambers motors or pumps that enable fluid to be introduced into the inner chambers at increasingly greater pressure.

A nitriding layer (13) is formed on the front surface side of a base material of a cylinder block (7) including an opening side end surface (7B) and each cylinder hole (12). Then, a piston sliding surface (12A) of each cylinder hole (12) is formed as a compound layer-removed hole (17) by removing a compound layer (16) that is located on the front surface side of the nitriding layer (13) by using polishing means such as, for example, honing and so forth. Further, a compound layer-removed surface (18) is formed on a part (A) where a compound layer-removed hole (17) and a cylinder inlet side tapered surface (12B) of each cylinder hole (12) intersect by using the polishing means such as, for example, the honing and so forth. This compound layer-removed surface (18) is formed as a tapered-state inclined surface of an angle α.

A nitriding layer (13) is formed on the front surface side of a base material of a cylinder block (7) including an opening side end surface (7B) and each cylinder hole (12). Then, a piston sliding surface (12A) of each cylinder hole (12) is formed as a compound layer-removed hole (17) by removing a compound layer (16) that is located on the front surface side of the nitriding layer (13) by using polishing means such as, for example, honing and so forth. Further, a compound layer-removed surface (18) is formed on a part (A) where a compound layer-removed hole (17) and a cylinder inlet side tapered surface (12B) of each cylinder hole (12) intersect by using the polishing means such as, for example, the honing and so forth. This compound layer-removed surface (18) is formed as a tapered-state inclined surface of an angle α.

Certain exemplary embodiments can provide a piston comprising a piston head, a connecting rod coupled to the piston head, a stabilizer bar, a retaining ring, and a stabilizer bar collar. The stabilizer bar collar defines one or more apertures. The one or more apertures are constructed to receive the stabilizer bar. The piston is constructed to reduce energy losses in an engine comprising the piston.

According to at least one aspect, the present disclosure provides a piston pump comprising: a piston unit configured to reciprocate by driving of a motor cam; a sleeve unit disposed to surround at least a part of the piston unit and having a space in which brake oil is stored; and a check valve unit facing the sleeve unit and discharging the brake oil to an outside of the sleeve unit when a pressure of the brake oil increases, wherein the piston unit includes a first piston having a first end in contact with the motor cam and reciprocating, a second piston having a first end coupled to a second end of the first piston and configured to press the brake oil, and a spring cap coupled to a second end of the second piston and disposed to accommodate an inlet spring therein.

According to at least one aspect, the present disclosure provides a piston pump comprising: a piston unit configured to reciprocate by driving of a motor cam; a sleeve unit disposed to surround at least a part of the piston unit and having a space in which brake oil is stored; and a check valve unit facing the sleeve unit and discharging the brake oil to an outside of the sleeve unit when a pressure of the brake oil increases, wherein the piston unit includes a first piston having a first end in contact with the motor cam and reciprocating, a second piston having a first end coupled to a second end of the first piston and configured to press the brake oil, and a spring cap coupled to a second end of the second piston and disposed to accommodate an inlet spring therein.

A hydrostatic axial piston pump has adjustable swept volume and is configured for fluidic connection to a hydraulic motor of a hydrostatic propulsion drive in a hydraulic circuit. The hydrostatic axial piston pump includes an adjusting unit configured to adjust the swept volume. The adjusting unit has an actuating cylinder with a first actuating pressure chamber, in which a first actuating pressure can be set via a first pressure reducing valve. The first actuating pressure is dependent on a first current at a first electromagnet of the first pressure reducing valve. An electronic control device is configured to store a model of the first current in a manner which is dependent on a requested speed.

Systems, methods and devices are described providing a selective hydraulic or electrically powered prime mover that is a bi-directional power unit system, including movement within a device used to compress and/or expand a fluid and provide fluid movement. The use of a hydraulic power unit is involved and comprises at least a pump or other fluid moving device, a first set of selective control valves delivering pressurized fluid to the device(s), and a second set of selective control valves returning unpressurized fluid from the device(s), a reservoir comprising a compensator tank, a port for operation at ambient pressure, and a pressure measuring device measuring ambient pressure allowing for unbalanced flow to and from the device as well as thermal expansion or compression. The use of a multiport and in some cases a swashplate pump that incorporates the features and functions of several valves for the system is also described.