Hongze Valve
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bellows expansion joints
Bellows expansion joints, also known as metal bellows, corrugated compensators, or flexible connectors, are designed to absorb axial, lateral, and angular movements in pipeline systems. These joints are typically made from high-quality stainless steel such as SS304 or SS316L, offering excellent resistance to pressure, temperature, and corrosion.
Engineered for durability and precision, bellows expansion joints help reduce mechanical stress, compensate for thermal expansion, and prevent damage caused by vibration or misalignment. They are widely used in steam lines, exhaust systems, chemical plants, oil pipelines, and HVAC installations. Available with flanged, threaded, or welded ends, these joints are essential for maintaining system integrity under dynamic operating conditions.
Key Features
Technical Specifications
✅ bellows expansion joints Specification Table (DN32–DN1000)
| Nominal Diameter (DN) | Recommended Waves | Pressure Rating (MPa) | Effective Area (cm²) | Max OD (mm) | Length (mm) | Flange DZ/F (mm) | End DF/J (mm) |
|---|---|---|---|---|---|---|---|
| DN32 | 8 | 0.25 / 0.6 / 1.0 / 1.6 / 2.5 | 225 | 250 | 160 | 250 | 264 |
| DN40 | 8 | Same as above | 244 | 259 | 164 | 259 | 269 |
| DN50 | 8 | Same as above | 259 | 276 | 172 | 276 | 282 |
| DN65 | 6 | Same as above | 270 | 294 | 215 | 294 | 300 |
| DN80 | 6 | Same as above | 284 | 338 | 240 | 338 | 344 |
| DN100 | 6 | Same as above | 304 | 317 | 235 | 317 | 323 |
| DN125 | 6 | Same as above | 334 | 314 | 282 | 314 | 316 |
| DN150 | 5 | Same as above | 364 | 389 | 282 | 389 | 338 |
| DN200 | 4 | Same as above | 442 | 384 | 280 | 384 | 348 |
| DN250 | 4 | Same as above | 507 | 379 | 315 | 379 | 415 |
| DN300 | 4 | Same as above | 562 | 427 | 366 | 427 | 466 |
| DN350 | 4 | Same as above | 622 | 452 | 397 | 452 | 497 |
| DN400 | 4 | Same as above | 700 | 478 | 412 | 478 | 512 |
| DN450 | 3 | Same as above | 760 | 498 | 503 | 498 | 503 |
| DN500 | 3 | Same as above | 835 | 523 | 431 | 523 | 531 |
| DN600 | 3 | Same as above | 980 | 548 | 478 | 548 | 578 |
| DN700 | 3 | Same as above | 1110 | 590 | 490 | 590 | 590 |
| DN800 | 3 | Same as above | 1265 | 602 | 502 | 602 | 602 |
| DN900 | 3 | Same as above | 1186 | 689 | 689 | 689 | 689 |
| DN1000 | 3 | Same as above | 1286 | 692 | 692 | 692 | 692 |
✅ Technical Parameters – Metal bellows expansion joints
| Parameter | Unit | Typical Value / Range |
|---|---|---|
| Nominal Diameter | mm (DN) | DN32 – DN1000 |
| Design Pressure | MPa | 0.25 / 0.6 / 1.0 / 1.6 / 2.5 (customizable up to 6.4 MPa) |
| Working Temperature | °C | -40°C ~ +550°C (depending on materials) |
| Applicable Media | – | Water, Steam, Oil, Gas, Air, Chemical Fluids, etc. |
| Material – Bellows | – | Stainless Steel SS304 / SS316L / 321 |
| Material – Flange | – | Carbon Steel / Stainless Steel / Galvanized Steel |
| Connection Type | – | Fixed Flange, Loose Flange, Welded End |
| Movement Type | – | Axial, Lateral, Angular, Universal |
| Axial Compensation | mm | Typically 20–50 mm (varies by model and size) |
| Lateral Compensation | mm | Up to 30 mm (customizable) |
| Angular Deflection | degrees | Up to ±15° |
| Design Standard | – | GB/T 12777, EJ/T 1021, EN 14917, ASME B31.3 |
| Material | Properties | Application Purpose |
|---|
| SS304 | Good corrosion resistance, widely used | General pipeline systems, HVAC, clean water |
| SS316L | Excellent corrosion and acid resistance | Chemical, food, and pharmaceutical industries |
| SS321 | Good high-temperature resistance | Heat exchangers, boilers |
| Carbon Steel | High strength, economical | Low-pressure or uncritical applications |
| Galvanized Steel | Rust prevention for outdoor use | General construction piping |
✅ Maintenance Guide
• Inspect the joint regularly for deformation, leaks, or corrosion
• Check flange bolts for loosening and tighten if necessary
• Replace the joint if you find fatigue cracks or serious wear
• Clean dust or corrosive residue from the surface regularly
• Avoid long-term exposure to extreme heat or vibration
• Follow the manufacturer’s service life and replacement guidelines
What are the main functions of bellows expansion joints?
Bellows expansion joints absorb thermal expansion, reduce vibration, and compensate for movement in pipelines. They help prevent damage caused by temperature changes, mechanical movement, and misalignment, thus extending the life of the piping system.
What materials are used in the construction of bellows expansion joints?
Bellows expansion joints are typically made from high-quality stainless steel (such as SS304 or SS316) for the bellows, with flanges and tie rods made from carbon steel or stainless steel to ensure corrosion resistance and long service life.
Where are bellows expansion joints commonly used?
These joints are widely used in power plants, chemical and petrochemical industries, heating and cooling systems (HVAC), steam pipelines, and other industrial applications where temperature fluctuations and vibration must be managed.
Can bellows expansion joints be customized for special applications?
Yes, we provide OEM and ODM services. Custom sizes, lengths, flange standards, and materials are available to suit your specific pipeline design and operational requirements. Send us your drawings or specifications for a tailored solution.
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