A check valve is the simplest type of directional control valve used in hydraulic systems. Check valves stop the flow of fluid in one direction and allow free flow in the opposite direction. They are also known as non-return valves.
They are used to block pressure spikes, prevent oil lines from draining and block oil flow from the accumulators. Check valves can be in different structure for assembly. VU MM series are male-male threaded check valves.