Piston air valve type automatic pressure release valve of thermal production well

The utility model discloses a piston air valve type automatic pressure release valve of a thermal production well. The automatic pressure release valve comprises a valve body mounted on a needle type valve of a casing pressure gauge, wherein the valve body comprises two parts, namely an upper valve body and a lower valve body, a valve cavity is formed in the valve body, the upper valve body is connected with the lower valve body through a thread, an air valve is arranged at the middle part of the valve cavity, the valve cavity is divided into an upper valve cavity and a lower valve cavity, a filter screen is arranged at the air inlet end of the lower valve cavity, the filter screen is compressed by a piston spring, an exhaust hole is formed on the upper valve body, and a plugging device is arranged on the exhaust hole. Compared with the prior art, the automatic pressure release valve has the advantages of small volume, light weight, easiness in operation, automatic pressure release and no need of artificially