Metallic Expansion Joints

Product Description

Metallic Expansion Joints are flexible connectors designed to absorb thermal expansion, contraction, vibration, and misalignment in piping systems or ductwork. They use metal bellows as the primary flexible element and are widely used in high-pressure and high-temperature applications like power plants, refineries, chemical plants, and HVAC systems.

What Are Metallic Expansion Joints Made Of?

A typical metallic expansion joint contains:

1. Metallic Bellows Element

   • Made of stainless steel or other alloys (e.g., Inconel, Monel, Hastelloy) for corrosion and temperature resistance.

   • Corrugated design provides flexibility for axial, lateral, and angular movements.

2. End Connections

   • Weld Ends or Flanges for integration into the pipeline or equipment.

3. Optional Internal Components

   • Inner Sleeve (Flow Liner): Protects bellows from erosion, turbulence, and high-velocity media.

   • Outer Cover (Shroud): Provides mechanical protection and shields against environmental damage.

4. Optional Restraints & Hardware

   • Tie Rods: Control pressure thrust and limit movement.

   • Hinges or Gimbals: Enable angular movements while absorbing pressure thrust.

   • Limit Rods: Prevent over-extension or compression.

Functions of Metallic Expansion Joints

• Absorb thermal expansion and contraction of piping.

• Isolate vibration and noise from rotating machinery.

• Compensate for minor misalignment.

• Reduce load on anchors and equipment.

Types of Metallic Expansion Joints

1. Single Axial Expansion Joint  Absorbs axial movement only.

2. Universal Expansion Joint  Two bellows connected by a spool for large lateral movement.

3. Hinged Expansion Joint  Absorbs angular rotation in a single plane.

4. Gimbal Expansion Joint Handles angular rotation in multiple planes.

5. Pressure Balanced Expansion Joint  Compensates for axial/lateral movement while neutralizing pressure thrust.

Advantages

• High strength and durability under pressure and temperature extremes.

• Suitable for steam, gas, oil, and chemical pipelines.

• Longer service life compared to rubber or fabric joints.