What is a Rotary Union?

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

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What is a Rotary Union?

Also referred to as a rotary joint, media joint, rotary coupling, fluid swivel, swivel joint or fluid rotary union (FRU).

Rotary unions are engineered for each unique application taking into consideration media types, number of flow paths, temperatures, pressures, speeds, loads, and environments.

A rotary union functions by connecting a stationary input (supply) to a rotating part, allowing a moving connection to be preserved and permitting the flow of media (liquids, solids and gases).

Rotary unions are utilized in a wide range of industries, from compact rotary unions for semiconductor applications, to large and rugged-duty rotary unions for energy, defense and industrial applications. Learn more about What is a Rotary Union?

Primary Components

Primary Components of a Rotary Union: Retaining Ring Primary Components of a Rotary Union: Bearing Primary Components of a Rotary Union: Housing Primary Components of a Rotary Union: Seals Primary Components of a Rotary Union: Bearing Primary Components of a Rotary Union: Shaft
  • Shaft
  • Bearings
  • Seals
  • Housing
  • Retaining Ring

Fluid Sealing & Transfer

Media Types: Rotary Union Cross Section View

Rotary unions (swivel joints) may integrate multiple independent flow channels (passages) for the sealing and transfer of different types of fluid media simultaneously. Common media types include:

  • Chemicals
  • Coolants
  • Food Products
  • Gases
  • Oils
  • Steam
  • Water

Operating Parameters

Operating Parameter: Speed

Speed

Normal rotational speeds range from 0 to 1,000 RPM, with some high-speed rotary union applications requiring 10,000+ RPM.

Operating Parameter: Pressure

Pressure

Normal pressures range from 0 to 20,000 PSI [1,380 BAR], with some rotary union applications pushing the range of 40,000+ PSI [2,760 BAR].

Operating Parameter: Temperature

Temperature

Normal environmental and media temperatures for rotary union applications range from -150° F to +400° F. [-100° C to 200° C].

Video: How Do Rotary Unions Work?

Play Video: How Do Rotary Unions Work?

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