A hydrostatic drive includes at least one hydrostatic pump configured to supply at least one hydrostatic consumer and an apparatus for an energy recovery procedure of at least a part of the energy that is output by the consumer. An electronic control unit or at least one software component is further included, with which the energy recovery procedure is controlled in a variable manner and depends upon detected influencing variables.

A hydraulic system for a machine includes an implement pump, a valve, and an implement valve subsystem. The implement pump includes a load sensing control, and the valve controls the flow of hydraulic fluid to the implement pump. The implement valve subsystem includes one or more implement control subsystems to control movement of an implement. The valve is an electrohydraulic proportional relief valve and includes a solenoid configured to adjust the pressure of hydraulic fluid delivered to the implement pump proportionally to a current delivered through the solenoid.

A stability and control augmentation system (SCAS) actuator is operable for actuating a flight control surface of an aircraft. The SCAS actuator includes an actuator housing having a first aperture, a second aperture and a hydraulic chamber therebetween. A piston extends through the actuator housing. Fluid inlets are in fluid communication with regions of the hydraulic chamber. A first end portion of the piston is arranged to slide through the first aperture without a seal between the first end portion and the first aperture. A second end portion of the piston is arranged to slide through the second aperture without a seal between the second end portion and the second aperture. An intermediate portion of the piston is arranged to slide in the hydraulic chamber without a seal between the intermediate portion and the hydraulic chamber.

A system for detecting a type of hydraulic device. The system includes a hydraulic device. The system also includes a power supply having an engine and a controller. The controller is configured to detect a voltage of a signal from the hydraulic device, to categorize the signal as a type of signal of multiple types of signals based on the voltage, and to control a hydraulic output based on the voltage and the type of the signal.

A fixed displacement hydraulic pump match flow demand control system that includes a spool valve, a plurality of fixed displacement pumps and a control valve is provided. The spool valve includes a spool. The spool is configured to shuttle within a chamber of a housing based at least in part on a pressure difference between a first end and the second end of the chamber. A fluid flow from each fixed displacement pump of the plurality of fixed displacement pumps is in fluid communication with an associated input port to the spool valve. At least one output port of the spool valve is in fluid communication with a hydraulically operated device and at least one of another output port is in fluid communication with a return. The control valve is configured to adjust the location of the spool in the chamber to regulate fluid flow to the hydraulically operated device.

To reduce an increase in the electric power consumption of an electric motor according to the state of an electric power source at the start of driving of an actuator, and make it possible to use devices in an appropriate state in an electrically driven hydraulic construction machine including a driving system that drives a hydraulic pump by using the electric motor. For this purpose, a controller 50 sets a target relief pressure of a relief valve 3 to a normal relief pressure Pn (first relief pressure) when an operation lever device 44 is not being operated and a storage amount SOC(t) of a battery 62 (the state quantity of an electric power source) is equal to or larger than a threshold S1, and sets the target relief pressure to a reduced relief pressure Pr(t) (second relief pressure) lower than the normal relief pressure Pn (first relief pressure) when the operation lever device 44 is not being operated, and the storage amount SOC(t) of the battery 62 (the state quantity of the electric power source) is smaller than the threshold S1.

A method is provided for detecting and quantifying leaks in a gas network under pressure or vacuum. The gas network may have a sensor(s) capable of recording the status of a source(s), consumers, consumer areas or applications. The method includes: a start-up phase; a training or estimation phase; and an operational phase. The operational phase includes: reading out the first group of sensors; calculating or determining the value of a second group of sensors from the readings from the first group of sensors; comparing the calculated or determined values of the second group of sensors with the read values of the second group of sensors and determining the difference between them; determining, on the basis of a residual value analysis, whether there is a leak in the gas network; generating an alarm and/or generating a leakage rate and/or generating the corresponding leakage cost if a leak is detected.

An excavator includes a hydraulic oil holding circuit that is provided in an oil passage between a bottom-side oil chamber of a boom cylinder and a control valve and is closed when the boom is not lowered, and a controller. The controller releases a closed state of the hydraulic oil holding circuit when the excavator is in a predetermined unstable state, and controls a released state so that an acting velocity in a lowering direction of the boom becomes less than or equal to a predetermined reference.

Working equipment including a hydraulically movable arm arrangement for a crane, an electric motor, a hydraulic pump, and a pump controller. An equipment controller is arranged to determine a maximum flow limit from the pump in dependence of a comparison of a current limit received from a battery system and a current consumption monitored by the pump controller, and to compare the determined limit with required flow of hydraulic fluid from the pump needed to move the movable arm arrangement in accordance with operating signals, and if the result does not fulfil a rule of a set of fluid control rules, the controller adapts the operating signals to reduce flow of hydraulic fluid to at least one of a plurality of actuators according to a rule of a set of adaptation rules, such that at least one rule of the set of fluid control rules is fulfilled.

The improved hydraulic system utilizes a secondary hydraulic force control circuit that changes the gripping force on the load independently of movement of the clamp arms.