What is a “rotary joint” and how many types are there?

Process Optimization

A rotary joint or “steam joint” is a mechanical seal that connects steam piping to rotating drying cylinders.

Supply steam flows through the rotary joint into the dryer and condensed steam (i.e., condensate) flows out of the dryer through a second passage in the rotary joint or through a second rotary joint.

A single-flow rotary joint has one passage, either for steam or for condensate.

A dual-flow rotary joint has two passages, one for the steam and one for the condensate. A rotary joint can be either self-supported with internal carbon bushings or externally supported with support rods, support stands, or ring brackets.

The internal seals in rotary steam joints are made from a carbon graphite material. These seals are the mechanical wearing component so they must be monitored and replaced before they reach the end of their normal service life. 

Source: Kadant