A compact unit has an electric motor accommodated in housing parts (7, 55) of a unit housing (45) and driving at least one hydraulic pump and giving off heat at the same time, an air heat-exchanging device, and a fan (19) drivable to produce an air flow. A flow-conducting device (47, 55) divides the air flow at least in a first partial flow flowing around the electric motor and a second partial flow flowing to the heat-exchanging device in the unit housing (45). Alternatively, arranged in series, the air flow first flows against the electric motor and then the heat-exchanging device, or that the incidence of the air flow occurs at least partially in the reverse direction.

An apparatus for controlling one or more characteristics of a hydraulic system of an aircraft. The apparatus includes a heat providing element arranged to provide heat to the contents of a reservoir of the hydraulic system, and a processor arranged to control the operation of the heat providing element. A method of controlling heat provision to a hydraulic system of an aircraft and a system for controlling one or more characteristics of a hydraulic system of an aircraft.

An apparatus for controlling one or more characteristics of a hydraulic system of an aircraft. The apparatus includes a heat providing element arranged to provide heat to the contents of a reservoir of the hydraulic system, and a processor arranged to control the operation of the heat providing element. A method of controlling heat provision to a hydraulic system of an aircraft and a system for controlling one or more characteristics of a hydraulic system of an aircraft.

A thermal management system includes a first hydraulic system for circulating a first hydraulic fluid at a first temperature and a second hydraulic system for circulating a second hydraulic fluid at a second temperature that is higher than the first temperature. The thermal management system also includes a sealed heat transfer device coupled between the first hydraulic system and the second hydraulic system. The sealed heat transfer device is not in flow communication with either of the first hydraulic system and the second hydraulic system. The sealed heat transfer device is configured to transfer heat from the second hydraulic fluid to the first hydraulic fluid.

A thermal management system includes a first hydraulic system for circulating a first hydraulic fluid at a first temperature and a second hydraulic system for circulating a second hydraulic fluid at a second temperature that is higher than the first temperature. The thermal management system also includes a sealed heat transfer device coupled between the first hydraulic system and the second hydraulic system. The sealed heat transfer device is not in flow communication with either of the first hydraulic system and the second hydraulic system. The sealed heat transfer device is configured to transfer heat from the second hydraulic fluid to the first hydraulic fluid.

A work machine includes a mechanical arm and a hydraulic actuator coupled to the mechanical arm to move the arm between a first position and a second position. A valve is in fluid communication with the hydraulic actuator for supplying fluid to the hydraulic actuator. A pump is configured to discharge fluid to the valve. An engine is operatively connected to the pump. A coolant system is in thermal communication with the engine and includes a temperature sensor. A controller is in communication with the pump and the temperature sensor. The controller is configured to transmit a control signal to the pump to modify a flowrate of the pump and to adjust the flowrate of the pump in response to a signal from the temperature sensor that a temperature is at or above a set temperature value.

A cooler bypass valve assembly for an agricultural implement includes a cooler bypass valve configured to receive hydraulic fluid from a hydraulic supply. The cooler bypass valve position is adjustable between a first position that facilitates flow of the hydraulic fluid to a cooler bypass and restricts flow of the hydraulic fluid to a hydraulic fluid cooler, and a second position that blocks flow of the hydraulic fluid to the cooler bypass and facilitates flow of the hydraulic fluid to the hydraulic fluid cooler. The hydraulic fluid cooler is capable of reducing a temperature of the hydraulic fluid, and the cooler bypass directs the hydraulic fluid around the hydraulic fluid cooler. Additionally, the cooler bypass valve assembly includes a control assembly that controls the cooler bypass valve position based on the temperature of the hydraulic fluid.

A method of operating a hydraulic system of a plant to resume operation from a minimum operating temperature of the plant, the hydraulic system includes a plurality of electronically operated valves, the method including a first stage in which the valves are controlled to cycle fluid from a tank through a bypass valve and directly back to the tank until the temperature of the fluid in the tank has reached a first interim level; and a second stage in which the valves are controlled to cycle fluid from the tank through the pressure lines of the hydraulic system and back to the tank until the temperature of the fluid has reached a desired operating level. Further, a hydraulic system and a wind turbine include a rotor blade pitching arrangement with such a hydraulic system.

A method of operating a hydraulic system of a plant to resume operation from a minimum operating temperature of the plant, the hydraulic system includes a plurality of electronically operated valves, the method including a first stage in which the valves are controlled to cycle fluid from a tank through a bypass valve and directly back to the tank until the temperature of the fluid in the tank has reached a first interim level; and a second stage in which the valves are controlled to cycle fluid from the tank through the pressure lines of the hydraulic system and back to the tank until the temperature of the fluid has reached a desired operating level. Further, a hydraulic system and a wind turbine include a rotor blade pitching arrangement with such a hydraulic system.

A hydrostatic valve arrangement for flushing pressure medium from a working line of a hydraulic circuit includes a flushing valve with a first flushing connection for connecting to a first working line and an output connection for connecting to a pressure medium sink. The arrangement also includes a pressure valve arranged in a pressure medium flow path of the arrangement from the output connection in the direction of the pressure medium sink. The pressure valve has a valve body on which a force equilibrium is formed. The force equilibrium includes a pressure equivalent that acts on the valve body in a direction that blocks the pressure medium flow path and an opening pressure that acts in a direction that opens the pressure medium flow path and is dependent on the pressure at the output connection. The arrangement further includes an adjusting device for shifting the force equilibrium.