I. Basic Parameters and Structural Features

1. Nominal Diameter: DN150 (6-inch imperial, pipe outer diameter 168.3mm)
2. Structural Types:
   • Single-axial type (most common, axial compensation 15–50mm)
   • Hinge type (suitable for angular displacement, compensation angle ≤15°)
   • Universal type (combined lateral and angular compensation)
3. Material Combinations:
   • Bellows: 304/316L stainless steel (standard), Hastelloy (corrosion-resistant), Inconel (high-temperature)
   • End pipes: Q235B (carbon steel), 20# steel (high-temperature), 316 stainless steel (corrosion-resistant)
   • Insulation layer: Ceramic fiber (temperature ≤1200℃), rock wool (temperature ≤600℃)

II. Key Technical Performance Indicators

III. Typical Application Scenarios

1. Industrial Pipeline Systems
   • Steam transportation: DN150 main steam pipeline in thermal power plants (250℃, 1.6MPa), compensating 32mm axial expansion (calculated for 100m pipeline with 200℃ temperature difference).
   • Chemical media transportation: Hot oil pipeline in styrene plants (300℃, 0.8MPa), using 316L stainless steel bellows with PTFE lining for corrosion protection.
2. Building and Municipal Engineering
   • District heating: DN150 water supply pipeline in community heating stations (130℃/70℃), paired with flange-type compensators for 28mm compensation and 15dB noise reduction.
   • Air conditioning chilled water: DN150 chilled water pipes in commercial buildings (7℃/12℃), using rubber bellows for both displacement compensation and vibration reduction.
3. Environmental Protection and Energy Engineering
   • Flue gas treatment: DN150 flue gas pipeline in waste incineration plants (200℃, -5kPa), using 310S stainless steel + ceramic fiber insulation to resist acidic corrosion.
   • Gas systems: DN150 pipeline in natural gas regulating stations (-10℃, 0.4MPa), selecting low-temperature resistant 304L stainless steel with 20mm compensation.

IV. Installation and Selection Key Points

1. Selection Calculation
   • Thermal expansion formula: ΔL = α×L×ΔT (α=1.2×10⁻⁵/℃, L=pipeline length in m, ΔT=temperature difference in ℃)
   • Example: 50m carbon steel pipeline with 150℃ temperature difference, expansion ΔL=1.2×10⁻⁵×50×150=90mm, requiring a double compensator with ≥90mm compensation.
2. Installation Specifications
   • Axial compensators need fixed supports (spacing ≤4D, D=pipe diameter) and guide supports with spacing ≤1.5D.
   • Medium flow direction arrows must align with pipeline flow; flange connections require sealing gaskets (metal wound gasket/graphite gasket).
3. Considerations for Special Conditions
   • High-pressure scenarios (PN≥2.5MPa): Use multi-layer bellows (≥3 layers) + reinforcing ring structure; pressure test at 1.5× design pressure.
   • Corrosive media: Lined with PTFE (temperature ≤260℃) or sprayed with ceramic coating (temperature ≤1000℃); flanges with thrust rings to prevent bellows tensile failure.

V. Industry Standards and Certifications

• Domestic standards: GB/T 12777 General Technical Conditions for Metal Bellows Expansion Joints, GB 50316 Design Code for Industrial Metal Piping
• International standards: ASME B31.1 (Power Piping), EN 13480 (European Industrial Piping), API 6A (Oil and Gas)
• Special certifications: Nuclear power applications must comply with RCC-M; chemical explosion zones require ATEX certification.

VI. Common Failures and Solutions