Check valve valve for lifting movement along the channel centerline, and reliability, but the fluid resistance, suitable for smaller diameter of the occasion, can be divided into two kinds of straight-through and vertical. Straight lift check valves generally only be installed in horizontal piping, and generally vertical lift check valve should be installed in a vertical pipe. Swing check valve flap around the shaft rotates, the fluid is generally less than lift check valve, which applies to the larger diameter of the occasion.