Abstract: The invention is a pipe rupture valve having an internal servovale that comprises a valve piston that, in a setting at a steering edge, blocks the connection between two internal pressure connections of the servovalve. At a distance axially to said steering edge the valve piston has an additional steering edge that separates, sealed against fluids, a pre-loaded spring of the valve piston (or a spring area accommodating this spring) from the pressure connections.

Abstract: A pilot-operated proportional pressure limiting valve with a pilot valve, with a main piston which can be acted on in closing direction by pressure prevailing in a control chamber and in opening direction by pressure prevailing in an inlet, with a control oil nozzle device between the inlet and the pilot valve and with a damping nozzle device between the control chamber and the pilot valve, wherein the total hydraulic resistance of the damping nozzle device is variable as a function of the stroke of the main piston. The damping nozzle device comprise a radial hole in the main piston, and in the closed position of the main piston the radial hole debouches towards the outside in the region of a radially narrow annular slot and, after a given stroke of the main piston, in the region of a radially wide annular slot.