A non-return valve, also known as a check valve or one-way valve, is a type of valve used in irrigation systems to allow water to flow in one direction while preventing backflow or reverse flow in the opposite direction. It ensures that water flows only in the desired direction, preventing the loss of pressure and potential contamination of the water source.

Non-return valves are an important component of irrigation systems to prevent backflow and ensure the proper flow of water. By maintaining the desired direction of water flow, they contribute to the overall efficiency and reliability of the irrigation system.