Rotary unions, also known as rotating unions, rotary joints, or swivel unions, are critical components that transfer fluids, such as steam, water, hydraulic oil, air, or other media, from a stationary source to a rotating part. These devices are widely used in industries such as automotive, chemical processing, paper manufacturing, food and beverage, and plastics extrusion. Understanding the different types of rotary unions is essential for selecting the right product to meet your application’s pressure, temperature, and media requirements.
Single-passage rotary unions feature one channel or port for transferring a single fluid or gas stream. They are commonly used in applications where only one medium needs to be transferred, such as steam or water supply to rotating drums or cylinders. These unions are often made from stainless steel or brass, providing corrosion resistance and durability for moderate pressure and temperature conditions.
Multi-passage rotary unions are designed with multiple channels to simultaneously transfer several fluids or gases through the same rotating interface. This type is ideal for complex machinery requiring parallel flows, such as plastic and rubber extrusion equipment or multi-fluid cooling systems. The ability to handle multiple media streams increases operational efficiency and reduces the need for multiple unions.
Engineers design high‑pressure rotary unions to withstand elevated pressures and temperatures, often incorporating advanced mechanical seals such as hydrostatic and mechanical seal designs. These unions are suitable for demanding industrial environments like hydraulic systems, steam heating rolls, and chemical processing plants. Materials such as specialized alloys and stainless steel are typically used to enhance strength and corrosion resistance.
Manufacturers optimize low-speed rotary unions for applications with slower rotational speeds and intermittent operation. They often use elastomeric or plastomeric seals to provide effective sealing at lower pressures and temperatures. These unions are cost-effective and commonly found in pneumatic systems, light machinery, and food processing equipment.
Electrical rotary unions combine fluid transfer capabilities with the transmission of electrical power or signals. Engineers install them in wind turbines, rotating machinery, and automation equipment to maintain both media and electrical connectivity during rotation.
A: Base your choice on whether you need one fluid channel (single‑pass) or simultaneous multiple media transfers (multi‑pass).
A: Yes—select a union with compatible seal materials (e.g., PTFE for water, mechanical face seals for oil).
A: Steam unions use higher‑temperature‑rated materials and graphite or ceramic seals to withstand saturated steam.
Rotary unions are a critical part of dynamic fluid and gas transfer systems. Whether you require a high-speed rotary joint, a multi-port fluid swivel, or a vacuum-sealed rotary coupling, understanding the types and applications helps in choosing the optimal solution.
For industrial engineers, purchasing agents, or maintenance teams, investing in the right type of rotary union will ensure operational efficiency and system longevity.
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THE WORLD'S LEADING ROTARY UNIONS MANUFACTURERS
