i'm eager to know about sensing hydraulics

Load sensing hydraulic system
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. the variable displacement pump can go to its maximum displacement setting with the excess fluid generated by Optimizing the operating characteristics of the system . It includes a flow control valve connected to a directional control valve .
It has has an operating position such that fluid exhausted from a hydraulic jack is transmitted to a tank. A signal valve is disposed in a control pressure signal line for controlling fluid flow from a supply conduit to one end of the flow control valve.When the signal valve permits fluid flow through the signal line, the flow control valve is moved to a position to block fluid flow to the tank. This valve is connected to the directional control valve for realizing the blocking or fluid transmitting positions.

for more details visit this link:
http://freepatentsonline4977928.html