The valve body of CARX composite exhaust valve is in the shape of a barrel, and the valve internals include stainless steel float ball, lever and disc. The valve is installed at the pump outlet or the air in the water distribution pipeline. In order to improve the use efficiency of the pipeline and water pump, when negative pressure occurs in the pipeline, this valve quickly absorbs the outside air to prevent damage caused by negative pressure in the pipeline. When water is injected into the pipe, a large amount of air is discharged at the open position of the valve clack. When the air is exhausted, the valve is filled with water, and the float rises to drive the valve clack to close. Stop venting. When the water in the pipe is normally transmitted and closed, if there is air accumulated in the valve to a certain extent, the water level in the valve will drop, and the air will be discharged from the small hole. When the water pump stops, the water flow in the pipe is empty or meets the negative pressure in the pipe. At this time, the plug is quickly opened to inhale air to ensure the safety of the pipeline.