A rotating union is a fluid connector that transfers gas or liquid from a stationary inlet such as a pipe, tube, or hose to a rotating outlet that connects to a cylinder, spindle, or other moving mechanism. They’re also referred to as rotary unions, rotary couplings, rotary joints, and swivel joints. They are used anywhere fluid must be transferred from a stationary source to a rotating part. Typical uses range from automotive manufacturing and agricultural applications, to assembly lines and machine tools.

In this guide, we review selection criteria, operation parameters and installation of rotating unions.