Check Valve is a non-return valve that it allows the fluid to flow through it in one way direction. When the fluid return to the equipment or machine, it may cause to the equipment or machine broken easily such as Pump. So, the check valve is very useful in the system. There are several types of check valves such as Swing, Check Valve, Spring Check Valve, Re-silent Check Valve, Duo plate Check Valve and etc. Each check valves is suitable for each application.