Gewerkschaft Eisenhutte Westfalia, Gmbh

Werner Grommas

Walter Weirich

A pressure-relief valve device has the stem of a valve member guided within a sealed bore of a guide piece screwed into or onto a sleeve-like housing. A spring in the housing acts on a pressure disk to create closure force on the head of the valve member. A connector, which may provide a plug-in connection to some equipment to be controlled, is in screw-threaded engagement with the guide and can be removed to provide ready access to the valve member without disturbing the remainder of the assembly and its setting. The valve member has a piston opposite the head which fits in a recess in the connector. An end wall of the recess forms a stop limiting the closed position of the valve and an end face of the guide forms a complementing stop face limiting the open position of the valve.

Pressure-relief valve devices

A hydraulic control system for a mine roof support unit has a control valve assembly for controlling the hydraulic appliances of the unit, and an actuator for actuating the control valve assembly. The actuator has a valve block provided with a plurality of pairs of spool valves. The spool valves of each pair are detachably fixed in a pair of generally parallel bores formed in the valve block. Each pair of spool valves is provided with a respective rocker arm for actuating purposes. Each of the rocker arms is mounted on a respective cover plate, which covers the mouths of the corresponding pair of bores, and which is detachably secured to the valve block.

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Dortmund, Germany

Werner Grommas