Expansion Joints

Product Description

Expansion Joints (also called compensators or bellows expansion joints) are flexible devices installed in piping systems, ducts, and vessels to absorb dimensional changes caused by thermal expansion, contraction, vibration, or movement without inducing excessive stress on the system.

What Are Expansion Joints Made Of?

Expansion joints typically consist of the following elements:

1. Bellows Element

   • The core flexible component, usually made of stainless steel or other alloys.

   • Formed with corrugations (convolutions) to provide flexibility and absorb movement.

2. End Connections

   • Weld Ends, Flanges, or Threaded Ends for connecting to the pipeline.

3. Accessories (Optional)

   • Inner Sleeve (Flow Liner): Protects bellows from turbulence and erosion.

   • Outer Cover (Shroud): Shields bellows from mechanical damage and environment.

   • Tie Rods / Limit Rods: Controls pressure thrust and movement limits.

   • Hinges / Gimbals: For angular movement control in special designs.

   • Insulation Layer: For high-temperature applications.

Functions of Expansion Joints

• Absorb Thermal Expansion & Contraction: Compensate for length changes due to temperature variations.

• Reduce Vibration: Dampen vibrations from pumps, turbines, or compressors.

• Correct Misalignment: Compensate for minor installation or settlement deviations.

• Relieve Stress: Prevent excessive loads on pipes, anchors, and equipment.

Types of Expansion Joints

1. Axial Expansion Joint (Single Bellows)

   • Handles axial movement along the pipeline.

2. Universal Expansion Joint

   • Two bellows with a center spool for lateral movement.

3. Hinged Expansion Joint

   • Allows angular rotation in one plane only; resists pressure thrust.

4. Gimbal Expansion Joint

   • Allows angular movement in multiple planes.

5. Pressure Balanced Expansion Joint

   • Neutralizes pressure thrust while absorbing axial/lateral movements.

6. Rubber / Fabric Expansion Joints

   • For low-pressure, low-temperature ducting systems (e.g., HVAC).

Summary Table