1. Structure and Materials

• Main Structure:
  • Bellows: 304/316L stainless steel (thickness 0.4-0.6mm) with U-type or Ω-type corrugations, enhancing axial/lateral compensation capability.
  • Flanges/Nozzles: Q235 carbon steel or stainless steel (304/316), compatible with DN200 pipeline standards (e.g., GB/T 9119-2010 or ANSI B16.5).
  • Flow Guide: Built-in stainless steel deflector to reduce medium erosion on the bellows (suitable for high-velocity fluids or particle-containing media).
• Special Types:
  • Multi-layer Bellows: Improves pressure resistance (up to 4.0MPa) for high-pressure steam pipelines.
  • Outer Sheath: Carbon steel or insulation layer for low-temperature (≤-40℃) or high-temperature (≥400℃) working conditions.

2. Technical Parameters

• Nominal Diameter: DN200 (corresponding to pipe outer diameter 219mm).
• Working Pressure:
  • Standard type: 1.0MPa, 1.6MPa;
  • High-pressure type: 2.5MPa, 4.0MPa (custom multi-layer corrugations required).
• Temperature Range:
  • 304 stainless steel: -20℃~400℃;
  • 316L stainless steel: -196℃~600℃ (suitable for low-temperature liquid nitrogen or high-temperature flue gas).
• Displacement Compensation:
  • Axial extension: ≤25mm; axial compression: ≤35mm;
  • Lateral displacement: ≤30mm; angular deflection: ≤10°/m.

3. Product Features

• Multi-directional Compensation: Absorbs axial, lateral, and angular displacements simultaneously, resolving pipeline stress caused by thermal expansion, foundation settlement, or equipment vibration.
• Reliable Sealing: Bellows and flanges are welded using TIG (argon arc welding) with a leakage rate ≤1×10⁻⁶Pa·m³/s, meeting industrial pipeline sealing standards.
• Fatigue Resistance: Withstands 10,000 cycles of displacement testing (±20mm axial displacement) without cracks or leaks, ensuring a service life of over 10 years (in indoor dry environments).
• Flexible Installation: Weighs only 60% of flange-type expansion joints of the same 规格，reducing pipeline support loads and lowering installation costs.

4. Application Scenarios

• Industrial Pipelines:
  • Chemical industry: Acid-alkali solution pipelines (316L for corrosion resistance);
  • Power industry: Boiler steam pipelines, cooling tower circulation pipes;
  • Metallurgy: Cooling water pipelines in steelmaking workshops (resistant to high-temperature impact).
• Municipal Engineering:
  • Central heating networks (high-temperature water/steam);
  • Aeration pipelines in wastewater treatment plants (resistant to sewage corrosion).
• Construction Sector:
  • Air conditioning water circulation systems in high-rise buildings;
  • Fire-fighting pipelines (compatible with 1.6MPa pressure class).

5. Installation and Maintenance Notes

• Installation Requirements:
  • Ensure coaxial alignment of pipes and expansion joints (deviation ≤3mm) to avoid uneven stress on the bellows due to eccentric loads.
  • Reserve sufficient expansion space (≥1.2 times the designed compensation) for axial compensation.
  • Pre-stretch at room temperature (50% of total compensation) for high-temperature pipeline installation.
• Maintenance Tips:
  • Regularly inspect for corrosion, deformation, or welding leaks (recommended every 6 months).
  • Clean foreign matter (sediment, welding slag) accumulated between corrugations to prevent local wear.
  • Gradually pressurize to working pressure before restarting after long-term shutdown to avoid pressure shocks.

6. Compliance Standards

• China: GB/T 12777-2019 General Technical Conditions for Metallic Bellows Expansion Joints
• International: ISO 14930:2009 Metallic bellows expansion joints for piping systems