Rotary Unions - the history.

Before Rotary Unions the method of supplying water and steam to a rotating roll was to use stuffing boxes or packed glands. These sealing devices proved inefficient, however, as they would only work for a short time on higher temperatures, pressures or speeds.

During the 1930’s the first Rotary Union was designed and built. This sealing method eliminated the problems that occurred with stuffing boxes or packed glands and was a more economical method. The Rotary Union’s success is due to the seal.

During the 1940’s Rotary Unions became the preferred method of supplying a medium to rotating rolls. In the late 1940’s William Murray, the founder of Filton Limited, recognised the potential for his company to expand.  A few years of development, both from the market and technical aspects, and William Murray had a range of Rotary Unions available, ranging from ¼” to 3”.

The bellows seal used in Rotary Unions proved very successful, where, previously, packed glands with constant leakage was normal. The sealing efficiency of the bellows seal was that ball bearings next to the seal were unaffected by leakages, something that would have been impossible with a packed gland.

For some years, Rotary Unions were only used on applications using the medium of steam, water, oil and air. One of the first unusual fluids contained starch and sulphur dioxide, which meant that conventional materials were unsuitable. After some research, a Rotary Union constructed mainly of aluminium bronze and stainless steel was manufactured. This functioned well for an application associated with the production of corn flour.

As Filton’s name became associated with quality, many enquiries for applications beyond capabilities of the current range were received. This led to Filton designing a simple swivel joint. Over the years the range of Swivel Joints has expanded.

As requirements changed over the years, different designs were developed to meet the needs of the industry. While the early years were focused on sealing steam and water joints, today there are thousands of different configurations of standard and custom Rotary Unions meeting customers’ requirements.

If you have any questions or if we can help you with your applications you can contact us either by phone on +44 1926 423191 or emailing us on sales@filtonltd.co.uk or technical@filtonltd.co.uk