The capacity of the copper iron cylinder is very large, which is an important tool for suppressing fire. In winter, the Beijing air drying materials are dry and the water is condensed into ice. According to the practice in the palace, each large cylinder is equipped with charcoal fire, and the water is constantly distributed, which can both keep warm and prevent fire. The capacity of the copper iron cylinder is very large, which is an important tool for suppressing fire. In winter, the Beijing air drying materials are dry and the water is condensed into ice. According to the practice in the palace, each large cylinder is equipped with charcoal fire, and the water is constantly distributed, which can both keep warm and prevent fire.