An industrial rotating union, also known as a rotary joint, rotating fitting or rotary seal, enables a medium such as grease, water, air or steam to flow between a stationary pipeline and a rotating tank or drum without spillage or escape. These essential connections are used in almost every industry and application, from metals to food processing, textiles to robotics.

Rotating union distributors offer an almost endless variety of products, with modifications that allow media to flow in one direction, two directions, or multiple directions at once, and with seals designed to withstand a full range of temperatures and pressure loads. When contacting a supplier of rotating unions online, keep the following specifications in mind:

1. The dimensions of the space, usually known as the "envelope," in which your industrial rotating unions need to operate.

2. The system pressure the rotating union is expected to withstand.

3. The rotational speed the industrial rotating union must maintain.

Action Steps
The best contacts and resources to help you get it done

Get information about rotating unions to guide your selection

Rotating union manufacturers offer lots of helpful information to help you narrow your choices and select the industrial rotating unions that suit your applications.

I recommend: Check the information page at Nuraseal, where the company provides an extensive overview of rotary unions in general and their own Filtron line in particular; you can download the catalog from the info page. Deublin Company, a leading rotating union manufacturer, provides an interactive selection guide; refine your search by several criteria.

Choose rotating unions by media

Every industrial rotating union is designed to perform best with a particular medium. Purchase rotating unions designed for the media you're working with.

I recommend: Kadant invented the industrial rotating union for steam use more than 70 years ago, and they're still the leader in rotary joints for steam applications. When you need rotating fittings with a watertight seal, take a look at the Barco E-75 RS. Vektek makes a pneumatic rotating union with a full 360 degrees of rotation. For gas applications, select FerroTec's Ferrofluidic models.

Locate a supplier of industrial rotating unions for special applications

Beyond media, selection criteria for industrial rotating unions can include specialized applications. Look for a rotating union distributor that knows the needs of your particular industry and application.

I recommend: Moog Components Group produces fiber optic rotary joints (FORJ) for specialized military and aeronautics applications. Cobham Defense Electronic Systems is a rotating union manufacturer that concentrates on microwave rotary joints for radar and other defense uses. Duff-Norton's trademarked Rotary Unions line includes both general and specialized applications, including the 8000T designed for the textile industry. Kinequip Inc., a rotating union distributor, offers one-touch rotary fittings from a variety of rotating union manufacturers.

Seek out custom rotating union solutions

Even with thousands of standard rotating fittings out there, there will be times when you need to locate a supplier of industrial rotating unions that can offer customized solutions. Custom rotating union suppliers can arrange anything from slight modifications of standard products to fully customized machining.

I recommend: Dynamic Sealing Technologies provides integrated solutions for all your rotating union needs. Contact Scott Rotary Seals (SRS) for a full range of customization options. Talco Inc. specializes in customized rotating fittings for high speed, low torque applications. The engineers at Rotary Systems Inc. have designed more than 700 custom industrial rotating unions, many of which are now part of their general stock.

Tips & Tactics

Helpful advice for making the most of this Guide

• •  Contact your rotating union supplier to purchase replaceable seals and other accessories for rotary unions.