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What is a Rotary Joint

and what are the different rotary joint types?

A rotary joint, also referred to as a rotary union or rotating union, is a rotary sealing device that connects rotating equipment to fixed piping for the transfer of steam, water, thermal oil, coolant, hydraulic oil, air, and other media. 

Transferring media without leaks requires the proper sealing technology. The sealing technology used depends on process speed, pressure, temperature, and media. 

Types of Sealing Technology

DuraSeal™ Elastomeric O-Ring Seals

  • Lighter duty applications

  • Work well at low speeds and temperatures

Balanced Mechanical Seals

  • Sealing force increases only slightly as pressure increases

  • Extended seal life and reduced torsional loads

Pressure Mechanical Seals

  • Heavy duty applications

  • Spring force and fluid pressure push a seal ring against a polished metal or ceramic surface

  • Sealing force and load increase with pressure

  • Rotary joints mount directly to a rotating shaft

Mounting Methods

Externally Supported

  • Mounted with a bracket, lug, or other external support

  • Robust to thrust, side, and torsional loading

  • Requires a mounting surface

pt2x rotary joint


  • Mounts directly to a rotating shaft

  • Easily adaptable to install

  • Susceptible to side loading

  • Requires anti-torque rods or piping to prevent rotation

Complete Solutions

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