A Check Valve is a one-way valve that allows fluid to flow in a single direction while preventing backflow. It operates automatically, using the flow of the fluid to open or close the valve without any manual intervention. When the fluid flows in the desired direction, the valve opens to allow passage, and when the flow reverses, the valve closes to prevent backflow. Check valves protect pumps, compressors, and pipelines from damage, reduce water hammer, and maintain system efficiency. They are widely used in water supply, wastewater treatment, oil and gas, chemical industries, HVAC systems, and power plants. Check valves are available in various designs, including swing, lift, ball, and dual plate, to suit different pressure, flow, and application requirements.