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 hydraulic apparatus including an electronically commutated machine having a plurality of working chambers which are controlled on each cycle of working chamber volume to carry out active or inactive cycles of working chamber volume allows only a plurality of defined fractions of cycles to be active cycles to avoid generating frequencies of active cycles which cause low frequency resonances. The demand signal may be quantised into fractions m/n where n is an integer below a threshold selected to avoid repeating patterns of active cycles of more than a cut-off length.

A hydraulic apparatus including an electronically commutated machine having a plurality of working chambers which are controlled on each cycle of working chamber volume to carry out active or inactive cycles of working chamber volume allows only a plurality of defined fractions of cycles to be active cycles to avoid generating frequencies of active cycles which cause low frequency resonances. The demand signal may be quantised into fractions m/n where n is an integer below a threshold selected to avoid repeating patterns of active cycles of more than a cut-off length.

A reciprocating pump assembly includes a fluid end section having a pressure chamber and a plunger bore that fluidly communicates with the pressure chamber. The reciprocating pump assembly includes a plunger configured to be held within the plunger bore of the fluid end section, and a linear actuator operatively connected to the plunger such that the linear actuator is configured to reciprocate the plunger within the plunger bore during operation of the reciprocating pump to thereby pump fluid through the fluid end section.

A hydraulic device having: a plurality of main piston-cylinder arrangements, each of the respective pistons having a fixed stroke length and configured for axial reciprocation within their respective cylinder; a plurality of flow control valves for switching between a lockdown state and an unlocked state of one or more of the plurality of main piston cylinder arrangements during operation of the hydraulic device; and one or more control valves for directing the plurality of flow control valves between their respective unlock and lock positions.

A hydraulic device having: a plurality of main piston-cylinder arrangements, each of the respective pistons having a fixed stroke length and configured for axial reciprocation within their respective cylinder; a plurality of flow control valves for switching between a lockdown state and an unlocked state of one or more of the plurality of main piston cylinder arrangements during operation of the hydraulic device; and one or more control valves for directing the plurality of flow control valves between their respective unlock and lock positions.

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.

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.

A hydraulic circuit arrangement includes a plurality of electronically-commutated pumps providing flow to a common hydraulic line, the plurality of electronically-commutated pumps including one or more quantized electronically-commutated pumps and one or more unquantized electronically-commutated pumps. A controller includes a pressure controller and a flow divider. The pressure controller is configured to receive a pressure signal corresponding to the pressure within the common hydraulic line, to compare the pressure signal to a demanded pressure, and to determine a target flow value required to produce the demanded pressure. The flow divider is configured to receive the target flow value and allocate the target flow value into a quantized target flow value for allocation among the one or more quantized electronically-commutated pumps and an unquantized target flow value for allocation among the one or more unquantized electronically-commutated pumps.

A hydraulic circuit arrangement includes a plurality of electronically-commutated pumps providing flow to a common hydraulic line, the plurality of electronically-commutated pumps including one or more quantized electronically-commutated pumps and one or more unquantized electronically-commutated pumps. A controller includes a pressure controller and a flow divider. The pressure controller is configured to receive a pressure signal corresponding to the pressure within the common hydraulic line, to compare the pressure signal to a demanded pressure, and to determine a target flow value required to produce the demanded pressure. The flow divider is configured to receive the target flow value and allocate the target flow value into a quantized target flow value for allocation among the one or more quantized electronically-commutated pumps and an unquantized target flow value for allocation among the one or more unquantized electronically-commutated pumps.