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What is a
Rotary Union?

A rotary union or swivel joint is a mechanism used to transfer fluid (under pressure or vacuum) from a stationary inlet to a rotating outlet, preserving and isolating the fluid connection.

Also referred to as rotary joints, rotary couplings, fluid swivels or swivel joints; rotary unions are engineered to endure a large range of temperatures, pressures and speeds for a variety of conditions and environments.

Rotary unions typically function by connecting to an input and securing onto another mechanism while allowing a moving connection to be preserved.

Rotary unions are utilized in a wide range of applications; from miniature rotary unions for the semiconductor industry, to large and rugged-duty rotary unions for industrial applications.

Primary Components
of a Rotary Union

  • +Shaft
  • +Bearing
  • +Seals
  • +Housing

Media Flow

Operating Parameters

Application Example:

On an excavator, rotary unions allow hydraulic fluid to be transferred between the cab and track base while continuously rotating 360 degrees. The fluid supplies the track drive system allowing the excavator to move.

Application Example:
Wind Turbine

On a wind turbine, rotary unions supply hydraulic fluid to power the turbine's blade pitch control system used to maintain optimum blade angle to achieve efficient power output. Rotary unions integrate hydrodynamic seal technology to provide long-life, maintenance-free operation required for wind turbines in offshore environments.

Application Example:
Offshore Hose Reel

On an offshore hose reel, rotary unions (integrated with electrical slip rings) transfer hydraulic fluid, data and power signals through the reel hose down to subsea equipment. In some applications, pressurized hydraulics, power and data supply remotely operated vehicles (ROVs) allowing the control of subsea tools.

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