Mechanical self-closing quick-release combined drain valve

The utility model relates to the technical field of gas supply equipment, in particular to a mechanical self-closing quick-release combined drain valve which comprises a safety valve and a bottom valve, the safety valve comprises a pressure relief valve element and a safety valve body, a pressure relief cavity is formed in the safety valve body, the pressure relief valve element comprises a gas blocking plug, the bottom valve comprises a bottom valve body and a self-closing plug, and the self-closing plug is arranged in the bottom valve body. The bottom valve body is provided with an air leakage channel and further comprises an air leakage inlet. According to the mechanical self-closing quick-release combined discharge valve, when the safety valve is connected with the bottom valve, the safety valve pushes the self-closing part away from the gas release inlet, so that the gas release inlet is in an open state, external gas enters the gas release channel and the pressure release cavity conveniently, and when t