The working principle of the sewage exhaust valve is basically the same as that of the clean water exhaust valve. The main difference is that the sewage exhaust valve can be used in clean water pipelines, while the clean water exhaust valve cannot be applied to sewage pipelines. This valve adopts a lever-type soft seal structure, and its valve body size is twice as high as that of the clean water exhaust valve, preventing foreign matters such as dirt and sand from contacting the exhaust port sea