Which component helps to ensure fluid flow in one direction?

The check valve is designed specifically to allow fluid to flow in one direction while preventing backflow. This functionality is crucial in hydraulic systems, where maintaining a specific flow direction is necessary for the efficient operation of the system. By automatically closing when the fluid tries to reverse direction, the check valve ensures that the fluid movement is controlled and directed, which helps maintain system pressure and efficiency.

In contrast, the flow control valve regulates the flow rate of fluid but does not inherently prevent backflow. The pressure relief valve serves a different purpose by releasing excess pressure to protect the system from damage, rather than controlling flow direction. Lastly, a hydraulic actuator converts hydraulic energy into mechanical motion but does not influence the directional flow of the fluid itself. Thus, the check valve is the key component that ensures unidirectional fluid flow in a hydraulic system.