Optimizing Rotary Unions with VR Seals


In the realm of fluid dynamics and mechanical engineering, rotary unions play a crucial role by allowing the transfer of media such as liquids, gases, or electrical signals between stationary and rotating parts. The efficiency and reliability of these rotary unions largely depend on the seals used within them. One of the latest advancements in this field is the integration of VR seals. These innovative lip seals offer significant benefits, because of reduced friction and the option to be pre-greased, making them a game-changer in various industrial applications.

Understanding Rotary Unions

A rotary union, also known as a rotary joint, is a mechanical device designed to transfer media from a stationary source to a rotating component without leakage or contamination. Rotary unions are essential in numerous applications, including manufacturing, chemical processing, oil and gas, and food production. The integrity of these systems depends heavily on the performance of the seals used.

The Significance of Seals in Rotary Unions

Seals are critical in rotary unions as they prevent leaks and ensure a reliable and consistent transfer of media. Traditional seals, made from various materials, have been effective in many applications. However, as industries continue to demand higher performance and greater durability, advanced sealing solutions like VR seals have become increasingly important.

Introducing VR Seals

VR seals are a type of lip seal designed to offer reduced friction and the option to be pre-greased. This unique combination provides several advantages over traditional sealing methods, particularly in terms of efficiency and longevity.

rotary union with VR seals SAB and SAC

Figure 1 – rotary union equipped with VR seals

Key Benefits of VR Seals in Rotary Unions

  • Reduced Friction: VR seals are engineered to minimize friction between the rotating and stationary components. This reduction in friction translates to lower wear and tear, which extends the lifespan of both the seal and the rotary union itself.
  • Pre-Greased Option: The ability to pre-grease VR seals ensures optimal lubrication from the start. This feature reduces the need for frequent maintenance and provides a consistent performance over time, enhancing the reliability of the system.
  • Enhanced Durability: The materials and design of VR seals contribute to their durability, making them suitable for high-demand applications. They can withstand challenging conditions and maintain their integrity over extended periods.
  • Versatility: VR seals are adaptable to a wide range of applications, from automotive and aerospace to industrial machinery and petrochemical processing. Their ability to perform reliably in diverse environments makes them a versatile choice for many industries.
  • Further optimizations can be realized by using the VR low friction seal, as it reduces friction and enhances service life time.
rotary union with VR seals SAB and SAC greased

Applications of Rotary Unions with VR Seals

The integration of VR seals into rotary unions opens up new possibilities for various industries:

  • Automotive: In the automotive industry, rotary unions with VR seals are used in manufacturing processes involving high-speed rotation and fluid transfer, ensuring reliable performance and extended service life.
  • Chemical Processing: Chemical plants often operate with aggressive chemicals and high temperatures. VR seals in rotary unions can handle these extreme conditions, reducing downtime and maintenance costs.
  • Food and Beverage: Applications requiring strict hygiene and resistance to cleaning agents benefit from the pre-greased option of VR seals, ensuring a durable and safe sealing solution.
  • Oil and Gas: In the oil and gas sector, rotary unions are exposed to harsh environments and corrosive substances. VR seals offer the necessary durability and reduced friction to ensure continuous operation and longevity.


The advancement of rotary unions with VR seals represents a significant leap forward in fluid dynamics and mechanical engineering. The reduced friction, pre-greased option, and enhanced durability of VR seals make them an invaluable asset in various industrial applications.

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