Hongze Valve
One-Stop Supplier for Rubber Joints, Bellows, and Waterproof Casings
Rectangular expansion joints
Rectangular expansion joints, also known as rectangular metal bellows expansion joints or rectangular duct expansion joints, are specially engineered for use in rectangular ducting systems such as flue gas pipelines, exhaust ducts, air handling units, and large ventilation systems. These flexible connectors absorb thermal expansion, vibration, and mechanical movement, effectively protecting ductwork from damage caused by temperature changes and system misalignment.
Made from stainless steel, carbon steel, or custom composite materials, our rectangular expansion joints offer superior flexibility, corrosion resistance, and easy installation for power plants, steel mills, chemical industries, and HVAC systems.
Key Features
Technical Specifications
| Nominal Size (mm) | Length (mm) | Width (mm) | Height (mm) | Flange Thickness (mm) | Bolt Hole Diameter (mm) | Bolt Quantity | Axial Movement (mm) | Lateral Movement (mm) |
|---|
| 300×400 | 400 | 500 | 150 | 10 | 18 | 12 | ±20 | ±15 |
| 400×600 | 500 | 700 | 180 | 12 | 18 | 16 | ±25 | ±20 |
| 500×800 | 600 | 900 | 200 | 14 | 22 | 20 | ±30 | ±25 |
| 600×1000 | 700 | 1100 | 220 | 16 | 22 | 24 | ±35 | ±30 |
| 800×1200 | 900 | 1300 | 250 | 18 | 26 | 28 | ±40 |
| Parameter | Unit | Value |
|---|---|---|
| Working Pressure | MPa | 0.1~2.5 |
| Burst Pressure | MPa | ≥1.5×Working Pressure |
| Temperature Range | °C | -20 ~ +450°C |
| Vacuum Resistance | kPa | ≥53.3 |
| Axial Movement | mm | ±20~±50 (based on design) |
| Lateral Movement | mm | ±15~±40 (based on design) |
| Angular Deflection | Degrees | 3°~8° |
| Applicable Media | – | Air, Hot Gas, Exhaust, Corrosive Gas |
| Component | Material Options |
|---|---|
| Bellows | Stainless Steel (304, 316, 321) |
| Flanges/End Fittings | Carbon Steel, Stainless Steel |
| Tie Rods | Carbon Steel (Zinc Coated), Stainless Steel |
| Internal Sleeve | Stainless Steel, Carbon Steel (optional) |
Inspect for damages before installation.
Align flanges accurately with mating pipes.
Use appropriate gaskets between flanges.
Tighten bolts evenly in cross pattern.
Avoid over-tightening bolts to prevent deformation.
Ensure bellows is not twisted during installation.
Periodically inspect for signs of leakage or corrosion.
Check bolts for proper torque periodically.
Ensure joints are free from obstruction.
Replace immediately if bellows show significant damage or deformation.
Regular maintenance intervals recommended every 6-12 months depending on operating conditions.
What are rectangular expansion joints used for?
Rectangular expansion joints are used to absorb thermal expansion, vibration, and movement in rectangular duct systems. They help prevent structural damage and maintain system integrity in flue gas ducts, exhaust systems, and large air handling units.
What industries commonly use rectangular metal bellows expansion joints?
These joints are widely used in power plants, steel mills, cement plants, chemical processing facilities, and HVAC systems—anywhere large rectangular ducts require flexibility and protection from thermal or mechanical stress.
What materials are available for rectangular expansion joints?
Our rectangular expansion joints can be made from stainless steel, carbon steel, or composite materials, with options for insulation layers and external coatings to suit specific temperature and environmental requirements.
Can you customize rectangular expansion joints for special applications?
Yes, we offer OEM and ODM services. Custom sizes, materials, flange types, and insulation options are available. Simply provide your drawings or specifications, and our engineering team will deliver a tailored solution.
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