Vulcanizing tank refers to the equipment for vulcanizing rubber products with steam. It is a fast opening pressure vessel that needs to be opened frequently. The vapor pressure of rubber during vulcanization is generally not more than 1MPa gauge pressure, and the temperature is about 180 ℃. The structure of the vulcanizing tank is cylindrical vessel with convex head. There are vertical and horizontal, one end of the head is quick open. Small curing tanks are opened and closed manually, while large ones are opened and closed hydraulically. When hydraulic opening and closing, use hydraulic cylinder to push the head to rotate a certain angle, then the locking teeth of the connection part between the head and the barrel can be locked or withdrawn. The head and the barrel are connected by a rocker arm. A conveying track is arranged at the bottom of the horizontal vulcanization tank, so as to facilitate the car with vulcanized rubber products to enter and exit. The vulcanizing tank is subjected to alternating load, and cracks often appear at the root of quick opening teeth. During the operation, the end cover can only be opened after the internal pressure is completely relieved. Therefore, the interlock device of pressure relief and quick opening must be installed to prevent the safety accident caused by opening the quick opening before the pressure is completely relieved.