Hydraulic priority flow control valve assemblies

The valve assembly 1 has an inlet port 3 from a pump 4, a first outlet port 6 to a power steering unit 8, a second outlet port 9 to an accumulator 10 of a braking system, and an excess flow port 13 to other services or a tank. A flow control valve 14 controls the fluid flow from the inlet port 3 to the ports 6, 9 and 13, and a load sensing port 42 communicates a load-dependent pressure signal from the power steering unit 8 to the valve 14 so as to provide priority fluid flow to the power steering unit 8. A pilot valve 32 is provided for cutting off the load-dependent pressure signal when the pressure within the accumulator 10 falls below a predetermined value so as to provide for fluid flow from the valve 14 to the accumulator 10, and in addition a pressure difference sensing arrangement 29, 60 communicates the pressure difference across a restrictor 56 to the valve 14 so as to provide fluid flow to the accumulator 10. This assembly permits priority flow from the pump 4 to the power steering unit 8, as well as providing for fluid flow to the accumulator 10, as necessary, and providing excess flow as available to a third device.