Rotary joint is the main part of the steam piping system of the wire dryer. Its role is to send steam from the static pipe through the steam inlet ring pipe to each heat exchange plate in the rotating drying cylinder. After heat exchange, The condensed water is collected into the rotary joint through a steam outlet ring pipe and led out. Generally, the outer tube of the rotary joint rotates, and the inner tube does not move. The inner and outer tubes of the rotary joint used on the wire dryer must be rotated. The dynamic and static ring is a sealing ring. The bellows only serves as a seal and a spring. It has advantages over general spring mechanical seals and improves the service life of the rotary joint.