A valve apparatus is disclosed for use in regulating the flow of fluid
between a closed hydraulic loop and a fluid source in a hydraulic
circuit, where the valve apparatus provides up to four different
functions including a check valve, a neutral valve, a relief valve and a
pressure rise rate valve. The apparatus includes a valve seat for
selectively permitting fluid communication between the closed hydraulic
loop and the fluid source, a sleeve member and a relief poppet in the
valve seat, a relief compression spring inside the sleeve and positioned
adjacent the relief poppet and the base of the slidable member, a valve
guide and an accumulator piston slidably mounted within the valve guide
to define an accumulator volume therein.