Abstract:
A hydraulic control device for moving at least one hydraulic consumer comprises at least one supply line, a discharge line or bypass line to which the hydraulic consumer is connected, and at least one pressure source and, optionally, a directional control valve. The line contains a dosing device for measuring a hydraulic medium dose by using a given compressibility of the hydraulic medium. The measured hydraulic medium dose either is supplied from the dosing device into the hydraulic consumer connected downstream or is discharged from the hydraulic consumer connected upstream into the dosing device. The dosing device comprises from upstream to downstream in series first and second blocking members which respectively can be switched into a leakage-free blocking position and into a through flow position, and a dead space between the blocking members. For dosing the hydraulic medium dose the blocking members are switched several times alternatingly.
Abstract:
A hydraulic controller for working machine according to the present invention, which presupposes an electronic control system where an integrated bleed-off valve common to hydraulic actuators is used for bleed-off control and the bleed-off valve is controlled by the secondary pressure of a proportional solenoid valve controlled by a controller, is constituted to compensate supply of a pressure oil for the hydraulic actuators even if the secondary pressure of the proportional solenoid valve is stopped, by providing, at the bleed-off valve, a fail-safe position with a fail-safe path which opens with an opening having smaller area than an unload opening.
Abstract:
A safety circuit for media-operated consumers, such as steam turbines or gas turbines, includes at least one first solenoid valve (1.1) which acts on a fluid circuit. An actuating device (9) can be connected to the fluid circuit, and acts at the same time on the operating behavior of the consumer. At least one other solenoid valve (1.2, 1.3) is connected at least to one of the other solenoid valves (1.1) such that only with simultaneous triggering of at least two solenoid valves (1.1, 1.2, 1.3) does at least one control valve (2.1), connected to the fluid circuit (10) act on the actuating device (9). Permanent verifiability can occur with simultaneous implementation of the safety function. A process for operating the safety circuit is also involved.
Abstract:
A pressurized fluid supply system, in which a plurality of pressure compensation valves are connected to a pump discharge line of a hydraulic pump in parallel, and direction control valves are provided at the outlet side of each pressure compensation valve to supply a discharged pressurized fluid from the hydraulic pump to a plurality of actuators. The pressure compensation valves include a check valve portion establishing and blocking communication between the pump discharge line and the inlet port of the direction control valve, and a pressure reduction valve portion for supplying a reduced pressure from the pump discharge line. The check valve portion shifts in a valve opening direction in response to an inlet pressure and shifts in a valve closing direction in response to an outlet pressure. The pressure reduction valve portion has a first and a second pressure chamber. Pressure in the first pressure chamber urges a valve element toward a position establishing communication between the inlet side and the outlet side, and a pressure in the second pressure chamber cooperates with a spring to urge the valve element to a position blocking communication between the inlet side and the outlet side, and biasing the check valve portion toward the valve closing direction. A load pressure of the actuator, to which the pressurized fluid is supplied, is introduced into the first pressure chamber and fluidly connects all of the second pressure chambers together.
Abstract:
A hydraulic control device that reduces the loss of the power of a pump in combined operation of boom lowering and arm pushing. A controller performs single control of increasing capacity of a first pump in accordance with increase in an operation amount of a boom operation member, in a single operation of the boom lowering. On the other hand, the controller restricts the capacity of the first pump compared to capacity in the single control, during a restriction control period when the combined operation of boom lowering and arm pushing is detected, and the operation amount of the boom operation member is a prescribed operation amount or more.
Abstract:
The invention relates to a turbine valve actuator (300) for Controlling at least one valve unit of a media-operated consumer unit, such as a steam or gas turbine, having an actuating part drive (102) which has a movable actuating part (104), at least one first media space (106) and at least one second media space (108), wherein a pressure build up in the first media space (106) attempts to cause a movement of the actuating part (104) in a first direction (R) and a pressure build-up in the second media space (108) attempts to cause a movement of the actuating part (104) in an opposing second direction (GR), wherein the first media space (106) can be supplied with a fluid in predeterminable amounts by means of a supply arrangement (110) and the second media space (108) is acted upon by an energy accumulator (112). The invention is characterised in that the energy accumulator is at least one hydraulic accumulator (112) which is provided with a preload pressure and is permanently connected to the second media space (108).
Abstract:
A hydraulic control device for moving at least one hydraulic consumer comprises at least one supply line, a discharge line or bypass line to which the hydraulic consumer is connected, and at least one pressure source and, optionally, a directional control valve. The line contains a dosing device for measuring a hydraulic medium dose by using a given compressibility of the hydraulic medium. The measured hydraulic medium dose either is supplied from the dosing device into the hydraulic consumer connected downstream or is discharged from the hydraulic consumer connected upstream into the dosing device. The dosing device comprises from upstream to downstream in series first and second blocking members which respectively can be switched into a leakage-free blocking position and into a through flow position, and a dead space between the blocking members. For dosing the hydraulic medium dose the blocking members are switched several times alternatingly.
Abstract:
A hydraulic tool having a ram or other working element propelled by pressurized fluid. The tool has a lever which is squeezed to develop fluid force in a pump. The fluid circuitry automatically operates the ram selectively at any one of three operating speeds and hence at three different magnitudes of force relative to the input speed of the lever as it is squeezed. The circuitry includes a principal supply subcircuit in which fluid flows directly from the pump to the ram, thereby establishing a normal speed mode of operation. A high speed subcircuit and a low speed subcircuit each operated by respective pressure responsive valves direct fluid ejected as the ram piston and pump piston advance to the respective rear sides of the ram piston and pump piston. This has the effect of accelerating the ram and operating at reduced force, thereby establishing a high speed mode of operation when resistance against the ram is minimal, and of decelerating the pump piston and operating at greater force, thereby establishing a low speed mode of operation when resistance is relatively high. In a preferred embodiment, the hydraulic tool includes a handle enabling grasping in pistol grip fashion and enabling ready squeezing of the lever.