The heavy-duty flip valve utilizes a conical ash hopper with beveled sealing surfaces, features ash unloading without wear and no other transmission structures, and is widely applicable in industries such as metallurgy, chemicals, power, light industry, building materials, construction, mining, cement, grain, food, and engineering. It serves as a ash unloading device for various environmental protection dust removal equipment and as a feeding and unloading device for equipment like mill ash hoppers, dryers, and dust collectors. It prevents wild wind from entering, hence also known as a double-locking wind valve.