A safety valve which has two fluidically interconnected safety valves, each of which has a 4/2-way valve function. Each safety valve has a first connecting port and a second connecting port, which are connected to each other in such a way that a fluid flow through the two safety valves, controlled by means of a control valve, to a fluid-actuated drive is prevented if the two safety valves simultaneously adopt a first switching position and such a fluid flow is possible if both valves simultaneously have a second switching state. One safety aspect results from the fact that the above-mentioned fluid flow is also prevented if the two safety valves adopt different switching states.

The present disclosure relates to the field of fluid process systems and discloses a manifold system for fluid delivery. The system comprises a first set of Solenoid Operated Valves (SOVs), a second set of SOVs, a plurality of isolating valves, at least one first shuttle valve, and at least one redundant shuttle valve. Each set of SOVs includes at least two SOVs arranged in parallel. The SOVs together form a series-parallel redundancy. Each isolating valve is coupled to an SOV and facilitates hot swapping of that SOV. The redundant shuttle valves provide redundancy to the first shuttle valve and facilitate the flow of a fluid from each of the first set of SOVs to each of the second set of SOVs, thereby promoting system safety and availability.

Control fluid power apparatus and related methods are disclosed. An example control fluid power apparatus includes a first housing having a first piston defining a first chamber and a second chamber, where the first chamber receives a control fluid and the second chamber receives a process fluid from a process system. The first chamber is oriented above the second chamber when the control fluid power apparatus is coupled to a control valve assembly. A second housing has a second piston defining a third chamber and a fourth chamber, where the third chamber receives the control fluid and the second chamber receives the process fluid. The third chamber is oriented above the fourth chamber when the control fluid power apparatus is coupled to the control valve assembly.

Control fluid power apparatus and related methods are disclosed. An example control fluid power apparatus includes a first housing having a first piston defining a first chamber and a second chamber, where the first chamber receives a control fluid and the second chamber receives a process fluid from a process system. The first chamber is oriented above the second chamber when the control fluid power apparatus is coupled to a control valve assembly. A second housing has a second piston defining a third chamber and a fourth chamber, where the third chamber receives the control fluid and the second chamber receives the process fluid. The third chamber is oriented above the fourth chamber when the control fluid power apparatus is coupled to the control valve assembly.

A hydraulic adjusting device, in particular for use in a power plant and/or a wind power plant, includes a double-acting adjusting cylinder that has an adjusting function for a working operation and for a special operation. The double-acting adjusting cylinder is configured to be pressurized with a working pressure medium. In order to satisfy the adjusting function in the special operation, the double-acting adjusting cylinder is further configured to be connected to a pressure medium reservoir that has a pressurized gas isolated from the working pressure medium. The adjusting cylinder has a working chamber configured for the adjusting function of the special operation, the piston area of which is coupled to a piston arrangement of the adjusting cylinder that is configured for the working operation or is configured to be coupled to the piston arrangement.

A power unit with manual override control for a hydraulic system having an initial state and at least one operational state is provided, comprising: a tank for storing hydraulic fluid that moves between a first chamber and a second chamber of a hydraulic cylinder; a pump that routes the hydraulic fluid in and out of the tank; a first relief valve; a first solenoid valve configured to shift between a plurality of positions based on the at least one operational state of the hydraulic system; a first check valve connected to the first solenoid valve; a manual override control unit comprising: a second check valve; and a second solenoid valve configured to shift between a plurality of positions based on activation of a manual override control, wherein the activation of the manual override control returns the hydraulic system from the at least one operational state to the initial state.

The present invention provides a work machine including a steering device that is very responsive to switching operations. The work machine includes: a proportional solenoid valve for outputting a first pilot pressure oil with a pressure responding to a steering signal; a solenoid valve for outputting a second pilot pressure oil with a predetermined pressure while the steering signal is outputted from the steering device; a switching valve capable of switching to a first state of outputting the first pilot pressure oil to a directional control valve and a second state of outputting the second pilot pressure oil to the directional control valve, while the first pilot pressure oil is outputted from the proportional solenoid valve and the second pilot pressure oil is outputted from the solenoid valve in parallel; and a controller to switch the switching valve from the first state to the second state in a case where a malfunction is detected in a main circuit ranging from the steering device to the directional control valve via the proportional solenoid valve and the switching valve of the first state.

The present invention provides a work machine including a steering device that is very responsive to switching operations. The work machine includes: a proportional solenoid valve for outputting a first pilot pressure oil with a pressure responding to a steering signal; a solenoid valve for outputting a second pilot pressure oil with a predetermined pressure while the steering signal is outputted from the steering device; a switching valve capable of switching to a first state of outputting the first pilot pressure oil to a directional control valve and a second state of outputting the second pilot pressure oil to the directional control valve, while the first pilot pressure oil is outputted from the proportional solenoid valve and the second pilot pressure oil is outputted from the solenoid valve in parallel; and a controller to switch the switching valve from the first state to the second state in a case where a malfunction is detected in a main circuit ranging from the steering device to the directional control valve via the proportional solenoid valve and the switching valve of the first state.

A valve assembly includes a linearly moving main slider, a pilot valve, a control oil inlet, and a control oil return. The pilot valve is designed as a 4/3 proportional directional valve, via which a first end face and an opposite second end face of the main slider can be fluidly connected selectively to the control oil inlet or the control oil return so that the main slider (20) is hydraulically movable by adjusting the pilot valve. The pilot valve is electrically adjustable depending on a target current. A position sensor is provided, with which an actual position of the main slider can be measured. A positioner is provided, with which the actual position can be regulated by adjusting the target current to a predefinable target position. The pilot valve is connected to the control oil return via a check valve. The check valve only permits fluid flow from the pilot valve toward the control oil return. The check valve is preloaded to a closed position by means of a first spring so that it opens at a predetermined opening pressure. The leakages at the pilot valve from the control oil inlet toward the check valve are designed to be so large that if the pressure at the control oil inlet exceeds the opening pressure by at least 2 bar, the opening pressure of the check valve is present immediately upstream of the check valve.

A hydraulic system for a construction machine having a protection device is disclosed, which can limit a flow rate of hydraulic fluid that is discharged from a hydraulic pump in accordance with a hydraulic fluid temperature and notify an operator of information on the hydraulic fluid temperature. The hydraulic system for a construction machine includes a hydraulic actuator operated by hydraulic fluid that is supplied from a hydraulic pump; a control valve installed in a flow path between the hydraulic pump and the hydraulic actuator to control a flow rate of the hydraulic fluid that is supplied from the hydraulic pump to the hydraulic actuator; an oil cooler installed in a return flow path from the control valve to an hydraulic fluid tank to cool the hydraulic fluid; a hydraulic fluid temperature sensor detecting in real time a hydraulic fluid temperature of the hydraulic fluid tank; a hydraulic pump regulator controlling a discharge flow rate of the hydraulic pump through adjustment of an inclination angle of a swash plate of the hydraulic pump; and a controller comparing the hydraulic fluid temperature detected by the hydraulic fluid temperature sensor with a predetermined hydraulic fluid temperature, and outputting a control signal to the hydraulic pump regulator so as to limit the discharge flow rate of the hydraulic pump to or below a predetermined flow rate if the detected hydraulic fluid temperature is equal to or lower than a predetermined lower limit value, or equal to or higher than a predetermined upper limit value.