Abstract: Load sensing hydraulic systems conserve energy by generating only the fluid flow demanded by the system and at a pressure only slightly greater than the highest load pressure of the system. Optimizing the operating characteristics of the system for certain applications also caused the variable displacement pump to go to its maximum displacement setting with the excess fluid generated thereby not doing any useful work. The load sensing hydraulic system includes a flow control valve connected to a directional control valve and has an operating position in which fluid exhausted from a hydraulic jack is transmitted therethrough to a tank. A signal valve is disposed in a control pressure signal line for controlling fluid flow therethrough from a supply conduit to one end of the flow control valve. When the signal valve is blocking fluid flow through the signal line, the flow control valve is in the above-noted operating position.

Abstract: The invention is concerned with an improvement in a hydraulic reservoir which comprises a tank having internally thereof filter means attached longitudinally between a first and a second generally parallel side thereof, said filter means including generally tubular filter element means extending generally longitudinally between said first and second sides of said tank and means for introducing a hydraulic fluid from an exterior of said tank to an interior of said element means from adjacent said first side of said tank. The improvement of the present invention comprises a tube within said tank surrounding said element means and extending longitudinally generally the length thereof, said tube including exit means therethrough through which said hydraulic fluid passes after passage thereof from the interior to an exterior of said element means; and means for compressibly sealing a first end of said tube adjacent said second side of said tank.