Due to the pressure of the inlet end medium in the pipeline, the valve is opened or closed against the spring resistance. When the inlet end of the medium pressure is lower than the outlet side, the spring will be pushed to the valve seat valve to close the valve to prevent the media countercurrent, so play a stop effect. Vertical check valve is widely used in chemical, liquefied petroleum gas, fluid and other industries. Check vales can be divided into lift check valve, swivel check valve and butterfly check valve according to structure.