Duff Norton Rotary Unions

Duff-Norton rotary unions group shot

The Duff Norton Rotary Union® (sometimes referred to as Rotating Joints) is a sealing device that connects rotating equipment to fixed piping for the transfer of steam, water, hot oil, coolant, hydraulic oil, air, and other media – or just about any other type of transfer application from a stationary source to a rotating source. Duff-Norton's single, dual and multi-passage Rotary Unions® can be found in a variety of industries and applications including oil and gas, construction, off-road machinery, food and beverage, aerospace, robotics, and medical devices.

How to get started selecting the right Duff Norton Rotary Union
  • Looking to replace or purchase an additional existing unit - simply send us a picture of the name plate on the cylinder's side.
  • Considering a rotary union for a new application - we recommend starting with the Selection Guide attached. The various rotary union designs differ slightly with your application parameters determining which RU is best: rotating speed, pressure (psi), temperature range, etc….

Features and benefits (options vary by product)

While rotary unions / rotating joints come in many shapes, sizes, and configurations, they typically have the same four basic components: housing, a shaft, a bearing (or bearings) and a seal.

Duff-Norton rotary union cutaway
  • Mechanical Seal

    The seal inside the Duff Norton rotary union prevents the medium (water, oil, air, etc.) from leaking outside the rotary union while in operation.

  • Bearing

    Duff Norton rotary unions may have only one or multiple bearings. The bearings are always used to allow a part of the joint, either the shaft or the housing, to rotate.

  • Shaft

    The shaft is the component that carries the medium through the rotary union into the drum or roll. In many cases, the shaft will turn with the drum or roll. In some cases, like in larger flanged rotary unions, the shaft may be stationary while the housing rotates. The bearings and seal are typically assembled around the shaft.

  • Housing

    The housing is the component that holds all of the other elements of the rotary union together. The housing may have one or more inlet / outlet ports depending on the application.

  • Left hand / right hand thread option on the end of the shaft

    These options should be selected based on the direction of the rotating drum or vessel, or both may be used if on opposing sides of the same drum or vessel.

  • Single or Dual flow configurations

    Either can be used for any type of Duff Norton rotary union pending the application demands.

Duff-Norton RU single flow diagram

...click to enlarge

Duff-Norton RU dual flow diagram

...click to enlarge

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