Patent ID: 7204266
Filing Date: 2007-04-17
Classification: F15B,Y10T

Abstract:
1. A pilot-operated pressure shut-off valve having a main control piston ( 20 ) which, when an upper system limit pressure in hydraulic system is reached, connects an inlet ( 12 ), via which hydraulic fluid is feedable to a hydraulic system, to an outlet ( 13 ) by taking up a first switching position and, when a lower system limit pressure is reached, separates from the outlet ( 13 ) by taking up a second switching position, and having a pilot valve arrangement ( 11 ) by which fluidic connection of a control space ( 26 ) adjacent to the main control piston ( 20 ) is changable in order to control the main control piston ( 20 ), and which has a valve housing ( 25 , 85 ), a first pilot piston ( 44 ) and a second pilot piston ( 48 ) accommodated therein, a first pilot spring ( 45 ), against which the first pilot piston ( 44 ) is adjustable hydraulically from a first into a second switching position, and a second pilot spring ( 49 ), against which the second pilot piston ( 48 ) is adjustable hydraulically from a first into a second switching position, and a first setting screw ( 78 ) with which the first pilot spring ( 45 ) is adjustable in order to set an upper system limit pressure, and a second setting screw ( 80 ) with which the second pilot spring ( 49 ) is adjustable in order to set a lower system limit pressure, and wherein the two pilot pistons ( 44 , 48 ), the two pilot springs ( 45 , 49 ) and the two setting screws ( 78 , 80 ) are arranged lying concentrically inside one another, with it being possible to adjust the two pilot pistons ( 44 , 48 ) mechanically completely independently of each other.