The valve that used to prevent backflow in a piping system is known as a check valve. It is also known as a non-return valve or NRV. The pressure of the fluid passing through a pipeline opens the valve, while any reversal of flow will close the valve. It allows full unobstructed flow and automatically shuts as pressure decreases. The exact operation will vary depending on the mechanism of valve.

Check valves (Non-return valve) are used in a piping system to prevent backflow. Discharge line of rotary equipment such as pump and compressor always fitted with a check valve to prevent backflow. The only function of a Non-return valve is to prevent backflow. There is no better alternative. Yes, you can choose the best check valve from the various available type that you have learned but you cannot supplement check valve with another valve