A crane, in particular a mobile crane, having a closed hydraulic circuit in which a hydraulic pump is hydraulically connected to at least one hydraulic motor via a feed and a discharge, and in which the feed is hydraulically connected to the discharge via at least one bypass which bypasses the at least one hydraulic motor, wherein the at least one bypass includes a continuously adjustable valve for variably controlling the fluid flow bypassing the at least one hydraulic motor. In addition, a corresponding control device and a corresponding crane control program for actuating a closed hydraulic circuit of a crane are provided.

A hydraulic unit includes a tank configured to be filled with a hydraulic fluid. The tank has at least one inflow connection and at least one outflow connection. A flow guide for the hydraulic fluid is formed between the inflow connection and the outflow connection. The flow guide is configured to have at least two 180 flow arcs configured to cool and calm the hydraulic fluid and to avoid dead zones.

A hydraulic unit includes a tank configured to be filled with a hydraulic fluid. The tank has at least one inflow connection and at least one outflow connection. A flow guide for the hydraulic fluid is formed between the inflow connection and the outflow connection. The flow guide is configured to have at least two 180 flow arcs configured to cool and calm the hydraulic fluid and to avoid dead zones.

A hydraulic circuit is disclosed. The hydraulic circuit may comprise an actuation valve configured to actuate a flow of hydraulic fluid to and from the hydraulic consumer, a first control valve in fluid communication with the actuation valve through a first pilot line and configured to displace the actuation valve to a first position when actuated, and a second control valve in fluid communication with the actuation valve through a second pilot line and configured to displace the actuation valve to a second position when actuated. The first pilot line and the second line may each have a fixed minimum back pressure sufficient to maintain dissolved air in the hydraulic fluid.

This disclosure relates to a system for reducing cavitation at a surface that moves relatively with respect to a first fluid. The system comprises a degasser configured to at least partially degas a second fluid. The system also comprises a reservoir in communication with the degasser and configured to house the at least partially degassed second fluid, the reservoir having an outlet that is arranged for directing the second fluid towards the surface. The system is configured such that the directing of the at least partially degassed second fluid towards the surface forms a boundary layer at the surface. The boundary layer is adapted to at least partially increase the negative pressure required to initiate cavitation at the surface so as to reduce the occurrence of cavitation during such relative movement.

A hydraulic fluid tank arrangement for a working machine is provided, the arrangement including a hydraulic fluid tank; an inlet portion for receiving hydraulic fluid into the hydraulic fluid tank; and an oil filter arranged in fluid communication with the inlet portion; wherein the hydraulic fluid tank arrangement further includes a gas removal device arranged in fluid communication with the oil filter downstream the inlet portion and upstream the oil filter for removing gas from the hydraulic fluid before the hydraulic fluid reaches the oil filter. A method for removing gas from hydraulic fluid contained in a hydraulic fluid tank arrangement is also provided.

A hydraulic fluid tank arrangement for a working machine is provided, the arrangement including a hydraulic fluid tank; an inlet portion for receiving hydraulic fluid into the hydraulic fluid tank; and an oil filter arranged in fluid communication with the inlet portion; wherein the hydraulic fluid tank arrangement further includes a gas removal device arranged in fluid communication with the oil filter downstream the inlet portion and upstream the oil filter for removing gas from the hydraulic fluid before the hydraulic fluid reaches the oil filter. A method for removing gas from hydraulic fluid contained in a hydraulic fluid tank arrangement is also provided.

A vortex reservoir for separation of an aerated portion of a hydraulic fluid includes an upper chamber and a lower chamber, in fluid communication with the upper chamber, having a lower chamber sidewall. The lower chamber includes a lower lower chamber and an upper lower chamber. The lower chamber includes a lower chamber partitioning plate. The lower chamber partitioning plate is located between the lower lower chamber and the upper lower chamber. The lower lower chamber is in fluid communication with the upper lower chamber via a gap between the lower chamber partitioning plate and the lower chamber sidewall.

A vortex reservoir for separation of an aerated portion of a hydraulic fluid includes an upper chamber and a lower chamber, in fluid communication with the upper chamber, having a lower chamber sidewall. The lower chamber includes a lower lower chamber and an upper lower chamber. The lower chamber includes a lower chamber partitioning plate. The lower chamber partitioning plate is located between the lower lower chamber and the upper lower chamber. The lower lower chamber is in fluid communication with the upper lower chamber via a gap between the lower chamber partitioning plate and the lower chamber sidewall.

A counter pressure valve arrangement for controlling a pressure level of a hydraulic fluid in a return line from a hydraulic actuator arrangement. The counter pressure valve arrangement comprises a counter pressure valve having: a moveable valve member; a counter pressure regulating port configured for being connected to the hydraulic actuator arrangement via the return line; a tank port configured for being connected to a tank or low pressure reservoir for storing low pressure hydraulic fluid; and a pump port configured for being connected to a source of pressurised hydraulic fluid. A first position of the valve member effects fluid communication between the pump port and the counter pressure regulating port for supplying pressurised hydraulic fluid to the return line (4), and a second position of the valve member effects fluid communication between the counter pressure regulating port and the tank port for discharging hydraulic fluid from the return line to the tank.