First, the lift check valve: valve flap go down the vertical center of the valve body sliding check valve. Lifting check valve can only be installed in the horizontal pipe, the high pressure small diameter check valve can be used on the ball valve. The shape of the valve body of the lift check valve is the same as that of the globe valve, so its fluid resistance coefficient is large.

Second, the swing check valve: A check valve that rotates around a pin outside the valve seat. Swing check valve is more common.

Third, the butterfly check valve: valve flap around the valve seat rotation of the check valve. Disc-type check valve structure is simple, can only be installed in the horizontal pipe, the seal is poor. 

Fourth, the pipeline check valve, the valve flap slides along the centerline of the valve body. Pipeline check valve is a new type of valve, its size is small, weight is weight, check valve is one of the direction of development. But the fluid resistance coefficient is slightly larger than the swivel check valve.