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 solenoid valve assembly has a valve body in which a spool is slidably mounted and operated by a solenoid having a coil. A manifold member has a plurality of flow paths for supplying and discharging pressurized fluid to and from ports of the solenoid valve assembly. An intermediate block is interposed between the valve body and the manifold member. The intermediate block has a plurality of through holes for connecting ports of the manifold member to ports on the valve body. At least one sensor is housed in the intermediate block for sensing at least one of pressure and flow in at least one of the through holes.

Provided is a construction machine including a hydraulic system having a hydraulic pump, and a first hydraulic actuator and a second hydraulic actuator which are driven by hydraulic oil supplied from the hydraulic pump. The construction machine includes a first flow rate detector that detects a flow rate of drain hydraulic oil discharged from the first hydraulic actuator, a second flow rate detector that detects a flow rate of drain hydraulic oil discharged from the second hydraulic actuator, and an abnormality determination unit that determines abnormality of the first hydraulic actuator, based on a detection signal from the first flow rate detector, and determines abnormality of the second hydraulic actuator, based on a detection signal from the second flow rate detector. The first flow rate detector and the second flow rate detector each have a moving body.

A hydraulic system for an agricultural baler includes: a hydraulic motor; a hydraulically driven component fluidly coupled to the hydraulic motor such that fluid flow between the hydraulic motor and the hydraulically driven component causes the hydraulically driven component to move between a first position and a second position; a flow sensor associated with the hydraulically driven component; and a controller operatively coupled to the flow sensor and the hydraulic motor. The controller is configured to: enter a learning mode to learn a driven movement of the hydraulically driven component from the first position to the second position; determine fluid flow between the hydraulic motor and the hydraulically driven component during the driven movement while in the learning mode; associate the determined fluid flow with the driven movement; and output control signals to the hydraulic motor to reproduce the associated fluid flow and reproduce the driven movement.

An apparatus for recuperating hydraulic energy in a working machine includes at least one first differential cylinder piston device with a differential cylinder and separate rod and bottom sides, and at least one hydraulic accumulator which is hydraulically connectable with the differential cylinder piston device. The potential energy of the differential cylinder piston device retracting under pressing load is at least partly storable in the hydraulic accumulator. The rod and bottom sides are connectable with each other via at least one brake valve for recirculating hydraulic fluid from the bottom side into the rod side.

A linear actuator system includes a linear actuator and at least one integrated pump assembly connected to the linear actuator to provide fluid to operate the linear actuator. The integrated pump assembly includes a pump with at least one fluid driver comprising a prime mover and a fluid displacement assembly to be driven by the prime mover such that fluid is transferred from a first port of the pump to a second port of the pump. The pump assembly also includes two valve assembles to isolate the pump from the system. The linear actuator system also includes a controller that establishes at least one of a speed and a torque of the at least one prime mover to exclusively adjust at least one of a flow and a pressure in the linear actuator system to an operational set point.

In an exemplary method of monitoring performance of a fluid driven actuator for a valve, pressurized fluid is supplied through an actuator supply line to an inlet port of the actuator during a first time period to operate the actuator from a normal position to an actuated position. Pressure changes corresponding to a fluid flow condition in the actuator supply line are measured during the first time period, with the measured pressure changes defining a valve cycle pressure profile including a first inflection point corresponding to movement of the actuator from the normal position to the actuated position. The valve cycle pressure profile is analyzed to identify a non-compliant condition in at least one of the valve and the actuator. An output communicating the identified non-compliant condition is then generated.

A linear actuator system includes a linear actuator and an integrated pump assembly connected to the linear actuator to provide fluid to operate the linear actuator. The integrated pump assembly includes a pump with two fluid drivers, each fluid driver comprising a prime mover and a fluid displacement assembly to be driven by the prime mover such that fluid is transferred from a first port of the pump to a second port of the pump. The pump assembly also includes two valve assembles to isolate the pump from the system. The linear actuator system also includes a controller that establishes the pump in a normal mode of operation in which the prime movers are independently driven and switches to a fail-safe mode of operation in which only one prime mover is operated.

A fluid system includes a variable-speed and/or a variable-torque pump to pump a fluid, at least one proportional control valve assembly, an actuator that is operated by the fluid to control a load, and a controller that establishes a speed and/or torque of the pump and a position of the at least one proportional control valve assembly. The pump includes at least one fluid driver that provides fluid to the actuator, which can be, e.g., a fluid-actuated cylinder, a fluid-driven motor or another type of fluid-driven actuator that controls a load. Each fluid driver includes a prime mover and a fluid displacement assembly. The fluid displacement assembly can be driven by the prime mover such that fluid is transferred from the inlet port to the outlet port of the pump.

A method of deactiving an underwater hydraulic device provides a hydraulic device that is capable of being operated under water, the device having a hydraulic cylinder with a pushrod and a piston. The device is lowered below a water surface with a hose reel that is located at the water surface area such as on a marine vessel. The hose reel includes first and second hydraulic hoses that connect to the cylinder on opposing sides of the piston. Fluid flow in the first and second hydraulic hoses is continuously monitored. The ratio of the volume of fluid flowing into the cylinder from one side of the piston to the volume of fluid flowing into the cylinder from the other side of the cylinder is continuously calculated with a computer or controller. The hydraulic device is deactivated if the ratio varies from a preset value. One embodiment includes a plurality of flow meters for measuring fluid flow to and from one or more hydraulicly powered apparatuses. In one embodiment outputs of the flow meters are analyzed to determine if the hydraulic system has a leak, and if a leak is detected, a warning is issued and/or one or more of the connected hydraulically powered apparatuses are shut down, and/or the hydraulic power supply is shut down.