Richard Voss Grubenausbau Gmbh

Grubenausbau Gmbh

Richard Voss

Wolfgang Voss

Support prop with integrated pressure limiting valve and nailed pipes

Pressure limiting valves intended for use in underground mining and tunnel construction are able to release the pressure medium discharged if an overload occurs without problems into the return line, since the occurring back pressure is directly neutralized in the pressure limiting valve. For this purpose a discharge of the pressure medium is provided even before the spring chamber, for which purpose the crossbores arranged there are constructed in such a way that they expand, forming a water chamber with increased volume. This water chamber is located in ring form around the valve piston that is exposed in this area and is connected via return bores to the return line. The water chamber with accordingly large volume makes it possible that the back pressure acts simultaneously on the spring and the valve piston, so that the described neutralization takes place.

Pressure-compensated pressure limiting valve

A pressure limiting valve with rates of flow of more than 8,000 l/min exhibits a valve casing comprising a control piston and valve piston. These valve casings are arranged inside the casing so as to be movable against corresponding springs, whereby the control piston and valve piston are separate units. The valve piston is arranged so as to be movable against an adjustment screw that is supported on the control piston side and has a through-bore that has a smaller diameter than the blind bore of the control piston. This special design of the valve ensures a uniform opening and reclosing of the pressure limiting valve for the described rates of flow, whereby suitable sealing rings consisting of Teflon are used in the area of the valve piston.

High-capacity pressure limiting valve

A pressure limiting valve with high flow rates, but in particular with a good adaptability to the respective conditions, is constructed so that the control piston and the valve piston are coordinated with separate valve cases, whereby these valve cases are connected to each other by way of a plug-in fitting which can be screwed into the valve case of the valve piston and has on the opposite side a standardized plug connection. In the center of this plug-in fitting is provided a center bore, so that the plug-in fitting which has a corresponding opening or blind hole on both sides permits the pressure medium to flow through. The blind hole in the valve piston itself is again connected via a through-bore to the compensation chamber on the opposite side, whereby the diameter of this through-bore is smaller than that of the blind hole of the control piston.

Pressure limiting valve with replacement control valve

For use in underground individual prop support, an individual prop valve is provided whose case integrates a return valve for setting, a non-return valve for drawing, and a pressure-limiting valve for securing the prop against overload. The valve case of the pressure-limiting valve is moved hydraulically if the case is also equipped on the drawing side with a coupling piece which has a gripping groove and locking shoulder. A push bolt which is loaded correspondingly by the pressure fluid acts on the valve case and moves it by a predefined length, so that the non-return valve is hereby opened and the pressure fluid is able to flow from the prop interior through the suction pump connection located on the setting side. Here the channels or spaces are proportioned in such a way that an increased amount of pressure fluid may be discharged, whereby this process is supported by a pump connected to the suction pump connection.

Individual hydraulic prop with filling/drawing valve and pressure fluid

A pressure limiting valve having high flow rates, especially for use as a safety valve with mine props and the like, uses a tubular main valve member whose interior communicates with the valve inlet and has lateral bores opening into the valve outlet when the bores are shifted past a sealing ring in the valve housing. A pilot valve body is received in the tubular valve and the valve spring bears upon the tubular valve. The main valve is shifted by differential pressure.

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Schwerte, Germany

Richard Voss