Patent ID: 7438800
Filing Date: 2008-10-21
Classification: B01D,Y10T

Abstract:
1. An arrangement for filtering hydraulic fluid through at least one filter element in a hydraulic circuit, having a feed channel which leads the unfiltered hydraulic fluid to the filter element, having a discharge channel which leads away the filtered hydraulic fluid out of the filter element, having a bypass line which connects the feed channel to the discharge channel, with the filter element being bypassed in the process, having a pressure switching valve which is arranged in the bypass line and, in the case of a certain change in pressure caused by the contamination of the filter, opens the bypass line, and having a means for indicating the state of contamination of the filter element, wherein the pressure switching valve ( 9 ) is designed, at the same time, as a means for indicating the state of contamination of the filter element ( 5 ); and a position-sensing device, which can sense, evaluate and indicate one or more certain positions of a control piston ( 17 ) which come about under the influence of the pressure of the hydraulic fluid at the filter element ( 5 ); the control piston ( 17 ) being coupled to an electrical evaluating and indicating unit ( 24 ); wherein the evaluating and indicating unit ( 24 ) is operatively connected to a device which, in accordance with the position of the control piston ( 17 ), reduces the quantity of hydraulic fluid which flows to the filter element ( 5 ) and the bypass line ( 8 ).