Automatic exhaust valve

The invention provides an automatic exhaust valve, relates to the technical field of valves, solves the problem that in the prior art, the automatic exhaust valve is only suitable for a relatively low-pressure environment, and comprises a lower valve cylinder, an exhaust nozzle, an ejector rod, a floating ball and a heavy hammer; an exhaust hole is formed in the exhaust nozzle, and the exhaust nozzle is connected to the top end of the lower valve cylinder; the ejector rod is arranged in the lower valve cylinder in a penetrating mode, and the ejector rod can move upwards in the axial direction to make contact with the exhaust hole of the exhaust nozzle to close the valve or move downwards to be separated from the exhaust hole of the exhaust nozzle to open the valve. The floating ball has the characteristic of floating on the water surface, and the floating ball is coaxially arranged on the ejector rod in a sleeving mode and located in the lower valve cylinder. The heavy hammer has the characteristic of being s