Example aspects of an over-pressure protection system and a method for using an over-pressure protection system are disclosed. The over-pressure protection system can comprise a main body comprising a main body housing, the main body housing defining a main body chamber; an incompressible fluid received in the main body chamber, the fluid defining a fluid pressure; a pressure sensor for measuring the fluid pressure of the incompressible fluid, the pressure sensor configurable an activated mode and a deactivated mode; a first barrier movable between a first position and a second position; wherein the over-pressure protection system is configurable an under-pressure configuration, wherein the pressure of the incompressible fluid is below a threshold pressure, and an over-pressure configuration, wherein the pressure of the incompressible fluid is equal to or above the threshold pressure; and a control system configuring the pressure sensor in the deactivated mode in the over-pressure configuration

In a spinning machine or winder comprising at least one pneumatic device (7) including a supply line (8) for a first pressure (P.sub.1), a regulating line (9) for an operating pressure (P.sub.2), a valve system (10), a manometer (13), and a data processing unit (14), the regulating line (9) is connected to the manometer (13) in such a way that the operating pressure (P.sub.2) is measured by the manometer (13). The valve system (10) comprises a first valve (11), which is connected to the supply line (8), or a first path (17) of a directional control valve (16) for feeding a pressure medium into the regulating line (9), and a second valve (12), which is connected to a surrounding atmosphere, or a second path (18) of a directional control valve (16) for draining the pressure medium from the regulating line (9), wherein the data processing unit (14), which is connected to the manometer (13) and to the valve system (10), is designed for opening the first valve (11) or the first path (17) and closing the second valve (12) or the second path (18) if the operating pressure (P.sub.2) is less than a first set value, and opening the second valve (12) or the second path (18) and closing the first valve (11) or the first path (17) if the operating pressure (P.sub.2) is greater than the first set value or a second set value, wherein the first pressure (P.sub.1) is greater than the operating pressure (P.sub.2).

A control device for a hydraulic machine such as a revolving excavator work machine having a structure that can cope with such an engine output decreasing environment as a work under a low atmospheric pressure at a high altitude without generating noise caused by engine rotation number increase. The control device corrects a control output value to be applied to an electromagnetic proportional valve for load-sensing valve control in a load-sensing type pump control system, based on a detected state quantity related to the engine output decreasing environment. When an engine speed-sensitive pump control system is adopted, a control output value generated based on a detected decrease in the actual engine rotation number is combined with a control output value generated by the load-sensing type pump control system.

The invention relates to a valve comprising a valve housing (2) which, for transport of a heatable fluid such as hydraulic oil, has at least one utility connection (A, B), at least one pressure supply connection (P), and at least one return connection (T1, T2), and a control slide (6) which is guided in the valve housing (2) in a longitudinally displaceable manner. The valve is characterised in that, in at least one position of the control slide (6), in which position the pressure supply connection (P) is at least partially separated from the utility connection (A, B), the heatable fluid arrives, proceeding from this pressure supply connection (P) and via a heat-emitting connection in the control slide (6), at the at least one return connection (T1, T2) as a loss volume flow which, serving as a heat source, heats at least regions of the control slide (6).

A hydraulic system for a working vehicle includes a first hydraulic pump to deliver pilot fluid to a control valve for a hydraulic actuator whose highest load pressure acts on a first fluid passage, and a second hydraulic pump to deliver hydraulic fluid whose pressure acts on a second fluid passage. A hydraulic controller is operable to control a load-sensing (LS) differential pressure between the highest load pressure and a delivery pressure of the hydraulic fluid from the second hydraulic pump. A third fluid passage to which the second hydraulic pump delivers the hydraulic fluid branches to a fourth fluid passage for flow of the pilot fluid. A solenoid valve is operable to change a pilot pressure of the pilot fluid for the hydraulic controller, and a controller is configured or programmed to control the solenoid valve to adjust the pilot pressure to change the LS differential pressure.

An inlet section for use in a hydraulic distributor including a valve body and a slider with a first area and a second area. The inlet section further including said slider being longitudinally slidable within the valve body between a first position in which it prevents passage of fluid from a high pressure line to a low pressure line, and a second position in which it enables passage of fluid. The inlet section further including a main spring active on the second area of the slider in a direction consistent with action of the second pressure and a control device of the slider. The control device of the slider includes a mechanical actuator member selectively active on the slider in a direction consistent with the action of the first pressure on the first area of the slider so as to force the slider in the second position.

A control arrangement for an arrangement of hydraulically couplable machines has an interface for hydraulic coupling of the machines, and a hydraulic machine for supplying pressure medium to at least one hydraulic consumer of the machines in accordance with requirements. An electronic control device is configured, in accordance with a load of the consumer, to generate an electronic control signal, which can be converted by a transducer of the control arrangement into a hydraulic control signal, in accordance with which the hydraulic machine can be operated.

To avoid a large size of a direction change-over valve and enable accurate supply flow control when providing a flow control valve at an upstream side of the direction change-over valve to change the relationship between supply flow rate and discharge flow rate for a hydraulic actuator. The configuration is to control a supply flow rate to a stick cylinder based on an opening area of the stick's direction change-over valve and stick's flow control valve, calculate a target opening area of the stick's flow control valve based on a target supply flow rate from hydraulic pumps A, B to the stick cylinder, the opening area of the stick's direction change-over valve, and a target differential pressure between hydraulic pump A and a load pressure of stick cylinder, and control the stick's flow control valve so as to keep the target opening area calculated.

A hydraulic system for a working machine is a load sensing (LS) system and includes a first hydraulic actuator and a first control valve for controlling the flow of hydraulic fluid from a pump to the first hydraulic actuator and for draining hydraulic fluid from the first hydraulic actuator, respectively, and a second hydraulic actuator and a second control valve for controlling the flow of hydraulic fluid from the pump to the second hydraulic actuator and for draining hydraulic fluid from the second hydraulic actuator, respectively. The hydraulic system further includes a first hydraulic circuit for providing an LS pressure for the first actuator and a second hydraulic circuit for providing an LS pressure for the second actuator. At least one of the first and second hydraulic circuits includes an offset valve for changing the LS pressure before providing the LS pressure to the pump.

1. Valve and valve device comprising a valve of that type. 2. The invention relates to a valve comprising a valve housing (33), which has at least one service connection (A, B), a pressure supply connection (P) and a return connection (T) and in which valve housing (33) a control slide (STS) is guided so as to be movable longitudinally in order to control these individual connections. The valve is characterised in that the supply pressure, which is applied to the pressure connection (P) in order to control a consumer (10, 12) connected to the service connection (A; B), is guided across at least one control side (56) of the control slide (STS) via an orifice plate (54) and a control channel (50), the control side (56) being positioned in a control chamber (58) in the valve housing (33) such that it can move and the control chamber (58) being connected to the return connection (T) via an additional orifice plate (59).