Hydac Fluidtechnik Gmbh

Hermann Albert

Peter Bruck

Philipp Hilzendegen

Alois Hoffmann

A valve assembly for regulating the pressure of a pressure medium () of a pressure medium pump () to at least one first consumer () includes a pilot-controlled pressure control valve () with a main piston () acted on by the pressure medium () and a pilot piston (). A pressure chamber () between a piston back side () of the main piston () and the pilot piston () can be relieved. A relief valve () is connected in a fluid-conducting manner to the pressure chamber (), opens when pressure at the load sensor (LS) represents an out-of-operation mode of the consumer (), and recirculates pressure medium () having a low pressure to a pressure medium reservoir () or to the pressure medium pump (). The relief valve () closes when the pressure at the load sensor (LS) represents an in-operation mode of the consumer ().

Valve assembly

A proportional pressure control valve includes a valve housing () with at least three fluid connections (). The valve can be connected to a hydraulic drive system with a pre-determinable consumer pressure. The valve can perform reliable valve switching functions even for low-viscous fluid media, and can reduce its susceptibility to disturbance variables. A valve piston () actively connected to a pilot seat () by an energy accumulator () can be controlled by a control device (). The consumer pressure on a fluid connection () acts on the valve piston () such that, according to the consumer pressure and the actuating force of the control device (), a fluid can flow between the two other fluid connections (and) in both directions inside the valve housing ().

Valve, especially proportional pressure control valve

A control device for hydraulically operated hoisting mechanisms used to raise and lower loads includes an electrically controllable throttle valve connected to a return line of the hoisting mechanism, and a pressure scale with at least one blocking position and one control position. The pressure scale operates in conjunction with an unblocking mechanism. When in its normal position, the pressure scale blocks the return line. The pressure scale assumes its control position in lowering of a load as a result of triggering of the unblocking mechanism. In the event of failure of the throttle valve, the pressure scale may be moved to its blocking position by the unblocking mechanism. In the event of failure of the pressure scale, the throttle valve assumes its blocking position. The load retention function is performed by two series-connected closed hydraulic actuators which can be electrically controlled individually. Both a hydraulic redundancy and an electric redundancy of the load retention function are provided as a result, so that higher safety requirements are satisfied.

Growing community of inventors

Lebach, Germany

Hermann Albert