A rotary union, also known as a rotary joint, swivel joint, or rotary coupling, is a precision mechanical device designed to transfer fluids, gases, or electrical signals between stationary and rotating components in a system. It is a critical component in a wide range of industrial applications where continuous rotation is required while maintaining a sealed connection for the transfer of media. Rotary unions are engineered to ensure reliable performance, minimal leakage, and extended service life, even under demanding operating conditions.The primary function of a rotary union is to enable the seamless transfer of media—such as water, air, hydraulic oil, steam, or coolant—from a stationary source to a rotating part of a machine. This is achieved through a combination of rotating and stationary seals, bearings, and housing components. The design of a rotary union must account for factors such as pressure, temperature, rotational speed, and the type of media being transferred to ensure optimal performance and durability.Rotary unions are commonly used in industries such as manufacturing, aerospace, automotive, packaging, and food processing. For example, in CNC machining, rotary unions are used to deliver coolant to rotating spindles, ensuring efficient cooling and lubrication during the machining process. In packaging machinery, they enable the transfer of air or vacuum to rotating heads for sealing or labeling applications. In the paper and printing industries, rotary unions are used to transfer ink, water, or steam to rotating cylinders.The construction of a rotary union typically involves high-quality materials such as stainless steel, brass, or carbon steel, depending on the application and media being handled. Advanced sealing technologies, such as mechanical seals or lip seals, are employed to prevent leaks and minimize wear. Some rotary unions are designed to handle multiple media types simultaneously, using multiple passages within a single unit.Maintenance and proper installation are crucial for the longevity of rotary unions. Regular inspection of seals, bearings, and housings can prevent premature failure and downtime. Additionally, selecting the right rotary union for a specific application—considering factors like pressure ratings, temperature limits, and rotational speed—is essential for ensuring reliable operation.In summary, a rotary union is a versatile and indispensable component in many industrial systems, enabling the efficient transfer of fluids, gases, or signals between stationary and rotating parts. Its precision engineering, robust construction, and adaptability make it a key enabler of modern manufacturing and processing technologies.