A rotary union (or rotary joint or swivel union) is a device that provides a rotating seal between two parts. It rotates 360 degrees on an axis or swivels part-way if full rotation is not required. This allows fluid to flow from a stationary source, like a pipe, to a rotating part or machine, such as a drum. This mechanism is used in a wide range of industries, from agriculture to plastics, so it needs to be extremely versatile.
