The invention relates to a method for actuating an electrically commutated fluid working machine (1), wherein the actuation of the electrically controllable valves (11) of the electrically commutated fluid working machine (1) is effected dependent on the fluid requirement and/or mechanical power requirements. In addition, on actuation of the electrically controlled valves (11) the electrical power required for actuating the electrically controllable valves is taken into account.

The invention relates to a method for actuating an electrically commutated fluid working machine (1), wherein the actuation of the electrically controllable valves (11) of the electrically commutated fluid working machine (1) is effected dependent on the fluid requirement and/or mechanical power requirements. In addition, on actuation of the electrically controlled valves (11) the electrical power required for actuating the electrically controllable valves is taken into account.

A hydraulic machine (1) comprising first and second brake elements (92, 93), a spring washer (65) tending to urge the first and second brake elements (92, 93) in a braking direction, and a brake release piston (61) configured to act on the spring washer (65) in a direction opposing the braking direction, the hydraulic machine being characterized in that the brake release piston (61) comprises a primary brake release piston (61a) associated with a primary brake release chamber (62a), and a secondary brake release piston (61b) associated with a secondary brake release chamber (62b), said primary and secondary chambers (62a, 62b) extending radially around the shaft (2) in such a manner that projections of the primary brake release chamber (62a) and of the secondary brake release chamber (62b) onto a plane perpendicular to a longitudinal axis (X-X) defined by the axis of rotation of the hydraulic machine (1) are superposed, at least in part.

A hydraulic machine (1) comprising first and second brake elements (92, 93), a spring washer (65) tending to urge the first and second brake elements (92, 93) in a braking direction, and a brake release piston (61) configured to act on the spring washer (65) in a direction opposing the braking direction, the hydraulic machine being characterized in that the brake release piston (61) comprises a primary brake release piston (61a) associated with a primary brake release chamber (62a), and a secondary brake release piston (61b) associated with a secondary brake release chamber (62b), said primary and secondary chambers (62a, 62b) extending radially around the shaft (2) in such a manner that projections of the primary brake release chamber (62a) and of the secondary brake release chamber (62b) onto a plane perpendicular to a longitudinal axis (X-X) defined by the axis of rotation of the hydraulic machine (1) are superposed, at least in part.

A modular power generator is provided. In some embodiments, the modular power generator can utilize or otherwise leverage one or more harvesting modules, each consisting of one or more nitinol elements, to harvest low grade thermal energy, converting it into high grade mechanical energy. The mechanical energy can be decoupled from the power generator by a mechanical energy storage mechanism, an energy transfer mechanism, and a control mechanism. Stored mechanical energy can be utilized on demand or asynchronously with respect to the generation of the mechanical energy.

A modular power generator is provided. In some embodiments, the modular power generator can utilize or otherwise leverage one or more harvesting modules, each consisting of one or more nitinol elements, to harvest low grade thermal energy, converting it into high grade mechanical energy. The mechanical energy can be decoupled from the power generator by a mechanical energy storage mechanism, an energy transfer mechanism, and a control mechanism. Stored mechanical energy can be utilized on demand or asynchronously with respect to the generation of the mechanical energy.

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.

An axial reciprocation device having a main piston and an anchor piston coupled to one another via a swivel joint interconnecting 20 a pair of connecting rods, the main piston positioned in a main cylinder bore and the anchor piston positioned in an anchor piston bore of a housing, such that the main piston is configured for axial reciprocation in the main cylinder bore; wherein variable positioning of the anchor piston along the anchor piston bore results in variable displacement of the main piston of hydraulic fluid with respect to an inlet/outlet port of the housing.

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.