Abstract: The invention relates to a pressure limiting valve, mainly for hydraulic mine props, which has a working space with an inlet opening connected to a high-pressure space and an outlet opening connected to low-pressure space in the operative position of the valve, a displaceable first valve member engageable with a valve seat within this working space in the shut-off position of the valve, a spring pressing the first valve member to the valve seat and in a given case, a spring sustaining the valve seat, suitably a gas spring and in which according to the invention the first valve member has transfer passages ensuring communication between the inlet opening and the outlet opening in the open position of the valve, as well as second valve member provided with a frustoconical head facing the cover plate and having a stem loosely fitted in a guide bore formed in the first valve member which is formed with an annular axial flange surrounding the head of the second valve member which is concentrically arranged within

Abstract: In a sediment raking device with a centrally arranged rotated torque tube, radially arranged booms and rake arms between said booms at a lower level a link rod is provided between the rake arms and the torque tube which is connected to the rake arm by a hinge and to the torque tube by a universal joint (FIG. 1).

Abstract: Displacement slurry pump equipped with known piston-rod drive, in which on a piston rod expediently three pistons are arranged at a distance of at least one stroke length, they are a liquid piston moving the auxiliary liquid free of solid matter, and on both sides thereof a slurry piston each moving on one side the slurry, on the other side, however, the auxiliary liquid. The liquid piston fits sealed to the liquid cylinder provided with liquid suction valves, whereas the two slurry pistons fit by slot to the slurry cylinders provided with slurry suction valves and slurry delivery valves. The effective section of the liquid cylinder is larger than the effective section of a slurry cylinder each. The slurry pump may be of single-operation or of double-operation, of one-cylinder or two-cylinder or three-cylinder construction.

Abstract: A container adapted to thoroughly mix fluid material, especially suspensions, comprising a tank provided with a vertical mixing pipe, a vertical air lifting pipe, a gas collecting chamber located at the upper end of the mixing pipe, and a connecting pipe affixed at one end to the collecting chamber and communicating therewith and affixed at its other end to the bottom of the air lifting pipe and communicating therewith.