| 摘要 |
PURPOSE:To properly control a filter element, by compensating an increase of pressure drop of the filter resulting from low temperature and accurately detecting the clogging of the element. CONSTITUTION:A temperature sensor 6 for detecting the temperature of a pressurized oil flowing through a pipe line 11 communicating a hydraulic pressure source 1 to a filter 2 and a pressure sensor 7 for detecting the pressure of the oil are respectively provided to output a pressure drop DELTAP1 in accordance with a signal inputted to a memory arithmetic device 8 in order to calculate the difference P2-DELTAP1 between a signal P2 outputted from the sensor 7 and the pressure drop DELTAP1 by a discriminating device 13. And, when said difference is positive, an alarming means 5a outputs a signal to inform the clogging of a filter 2. For detecting the clogging of an element in such a high pressure filter where an acutuator is placed behind the filter, a pressure sensor is provided to detect the pressure difference of the pressurized oil between the points before and behind the filter so as to apply the signal of this sensor to said discriminating device 13. |
