The valve function of flow-direction control means when you change the valve position, it can controlthe direction of fluid flow. Commonly this function could be found in the three way valves or the multi-port valve, it lets you decide which way the fluid will go.
They are capable to determine the path through which the fluid should flow in a circuit. We can use the directional control valve to direct the inlet flow to a specific outlet port. Besides changing the flow direction, the flow-direction control valve also have the function of stop and start the flow in the system.