The rotary joint is installed on the trunnion of the converter for steel producers to connect the converter and pipe passages, and transmit cooling, bottom blowing and top blowing mediums required for the converter. It can guarantee the continuous water diversion and air ventilation of the converter in the production process, realize the cooling of trunnions, backing rings and furnace crowns, and conduct argon (nitrogen) bottom blowing and bosh air cooling of the converter. It is an important component to ensure the continuous and safe production of the converter.