Check valves,non-return valves,are designed to prevent the reversal of flow in a piping system. These valves are activated by the flowing material in the pipeline.The pressure of the fluid passing through the system opens the valve, while any reversal of flow will close the valve. 

 API602 check valve  is for the small size high pressure check valves,which is made by forged steel.we normally make them in swing check valve,piston check valve(lift check valve).Available in three bonnet designs. The first design is the Bolted Bonnet, with male-female joint, spiral wound gasket, made in F316L/graphite. Ring joint gasket are also available on request. The second design is the welded bonnet, with a threaded and seal welded joint.