The present invention provides a method and system for providing on-site electrical power to a fracturing operation, and an electrically powered fracturing system. Natural gas can be used to drive a turbine generator in the production of electrical power. A scalable, electrically powered fracturing fleet is provided to pump fluids for the fracturing operation, obviating the need for a constant supply of diesel fuel to the site and reducing the site footprint and infrastructure required for the fracturing operation, when compared with conventional systems.

An injection molding system, water jet cutting machine or other industrial system has a synthetically controlled variable displacement fluid working machine which outputs hydraulic fluid to one or more fluid consumers, such as rams or hydraulic motors, through hydraulically stiff fluid retaining volumes and receives hydraulic fluid back from one or more fluid consumers through the same or other said hydraulically stiff fluid retaining volumes. Individual piston cylinder assemblies can be allocated to different outputs. There may be no valve between the machine and the consumers. A working chamber of the machine can be caused to undergo a motoring cycle to enable the machine to output more power than is received from a motor driving the machine. An accumulator can be used to provide a source of hydraulic compliance. The machine can be controlled using pressure control, flow control, feed forward control or variable power/variable power limit control.

An injection molding system, water jet cutting machine or other industrial system has a synthetically controlled variable displacement fluid working machine which outputs hydraulic fluid to one or more fluid consumers, such as rams or hydraulic motors, through hydraulically stiff fluid retaining volumes and receives hydraulic fluid back from one or more fluid consumers through the same or other said hydraulically stiff fluid retaining volumes. Individual piston cylinder assemblies can be allocated to different outputs. There may be no valve between the machine and the consumers. A working chamber of the machine can be caused to undergo a motoring cycle to enable the machine to output more power than is received from a motor driving the machine. An accumulator can be used to provide a source of hydraulic compliance. The machine can be controlled using pressure control, flow control, feed forward control or variable power/variable power limit control.

An apparatus comprising a synthetically commutated machine with one or more services, a prime mover coupled to the machine, a hydraulic circuit extending between the services and hydraulic loads to fluidically connect the services to the hydraulic loads such that groups of one or more services are fluidically connected to respective groups of one or more hydraulic loads. The apparatus configured such that the flow of hydraulic fluid to or from a group of services of the machine is controlled responsive to measuring a flow rate and/or pressure requirement of the hydraulic loads which are fluidically connected to the services, or receiving a demand signal indicative of a demanded pressure and/or flow rate based on a pressure and/or flow demand of hydraulic loads which are fluidically connected to the services.

A four-quadrant radial piston hydraulic device includes a housing, plunger assemblies, an eccentric spindle rotatably disposed on the housing, pilot-operated check valves one-to-one corresponding to the plunger assemblies, two-way cartridge valves one-to-one corresponding to the plunger assemblies, a distribution shaft and a confluence plate. A reversing slide valve is disposed on the confluence plate. A working method of a four-quadrant radial piston hydraulic device is also provided. When the radial piston hydraulic device is used as a hydraulic motor and a hydraulic pump, it is capable of realizing two-way rotation, which solves a limitation of valve flow distribution in motor application.

A four-quadrant radial piston hydraulic device includes a housing, plunger assemblies, an eccentric spindle rotatably disposed on the housing, pilot-operated check valves one-to-one corresponding to the plunger assemblies, two-way cartridge valves one-to-one corresponding to the plunger assemblies, a distribution shaft and a confluence plate. A reversing slide valve is disposed on the confluence plate. A working method of a four-quadrant radial piston hydraulic device is also provided. When the radial piston hydraulic device is used as a hydraulic motor and a hydraulic pump, it is capable of realizing two-way rotation, which solves a limitation of valve flow distribution in motor application.

A pump has at least one pump element that comprises a pump piston that is driven in a reciprocating movement by a drive shaft having at least one cam and that defines a pump working chamber which, during the suction stroke of the pump piston is selectively filled with pumped medium via an inlet valve. The at least one cam is a multiple cam having multiple cam delivery areas for the delivery strokes of the pump piston. The inlet valve is configured to be electrically actuated. The inlet valve is closed when the pump piston is situated in the cam delivery area to be used for the delivery. The inlet valve is opened when the pump piston is situated in a cam delivery area that is not to be used for the delivery. Cam profiles of the cam delivery areas of at least one multiple cam are of different design.

A system and method for machinery performing work with hydraulic actuators. Radial hydraulic pumps are aligned end-to-end along a common driveshaft axis to form a multi-pump assembly having a plurality of piston/cylinder units extending in a radial direction. Two or more piston/cylinder units are associated with one another to form multiple piston/cylinder groups. A plurality of control valves combines individual output flows from the two or more associated piston/cylinder units into respective common output flows for each respective piston/cylinder group. A plurality of flow control devices varies the common output flow from each respective piston/cylinder group by throttling inlet flow to the two or more associated piston/cylinder units in each respective piston/cylinder group. Each respective common output flow is directed from each respective piston/cylinder group to a hydraulic actuator on the heavy machinery to control its direction of movement.

A system and method for machinery performing work with hydraulic actuators. Radial hydraulic pumps are aligned end-to-end along a common driveshaft axis to form a multi-pump assembly having a plurality of piston/cylinder units extending in a radial direction. Two or more piston/cylinder units are associated with one another to form multiple piston/cylinder groups. A plurality of control valves combines individual output flows from the two or more associated piston/cylinder units into respective common output flows for each respective piston/cylinder group. A plurality of flow control devices varies the common output flow from each respective piston/cylinder group by throttling inlet flow to the two or more associated piston/cylinder units in each respective piston/cylinder group. Each respective common output flow is directed from each respective piston/cylinder group to a hydraulic actuator on the heavy machinery to control its direction of movement.

A pump unit for supplying fuel, preferably diesel oil, to an internal combustion engine has at least two cylinders (10), which are formed in at least one head (9), are slidingly engaged by respective pistons (13), and communicate hydraulically with respective fuel inlets (11) in the cylinders (10) via respective interposed intake valves (15) provided with respective valve bodies (16) incorporated in the head (9); the inlets (11) of all the cylinders (10) being closed by a single cover (33) fixed to the head (9).