System for allocating fluid from multiple pumps to a plurality of hydraulic functions on a priority basis

A control valve assembly for a hydraulic system having a variable displacement first pump and a second pump which supply fluid from a tank for powering a plurality of hydraulic actuators, the control valve assembly comprising:

• a supply conduit connected to convey fluid from the first pump for conveying fluid to the plurality of hydraulic actuators;
• a return conduit for conveying fluid to the tank;
• a flow summation node coupled to a displacement control port for the first pump;
• a plurality of control valves, each having a variable metering orifice for controlling flow of fluid from a first inlet to a hydraulic actuator, and having a variable source orifice through which fluid flows from the supply conduit to the flow summation node, wherein in the variable source orifice increases in size as the variable metering orifice in the same control valve increases in size, and each control valve including a variable bypass orifice that decreases in size as the variable metering orifice in the same control valve increases in size, wherein the variable bypass orifices of the plurality of control valves are connected in series between a bypass node and the return conduit thereby forming a bypass passage, wherein the bypass node is operatively connected to receive fluid from the second pump and is coupled to the flow summation node;
• a plurality of first flow direction control devices, each providing a path through which fluid is able to flow only from the supply conduit to the first inlet of one of the plurality of control valves;
• and
• a plurality of second flow direction control devices, each providing another path through which fluid is able to flow only from the bypass passage to the first inlet of one of the plurality of control valves.