Main Functions Of Expansion Joints

Specific functions include:
1. Thermal Compensation: Absorbing axial, lateral, or angular displacements in pipelines caused by temperature changes;
2. Vibration and Noise Reduction: Mitigating vibration energy transmitted by mechanical vibrations or fluid impacts;
3. Stress Reduction: Reducing additional stress on pipelines caused by displacement, preventing flange leaks or weld cracking;
4. Simplified Installation: Compensating for installation deviations and reducing the requirements for pipeline alignment accuracy.

Technical Principle: Expansion joints typically employ a bellows structure (metal or non-metallic material), achieving displacement compensation through the elastic deformation of the corrugations. For example, axial compensation types absorb length changes through corrugation compression/tension, while universal joint types can deflect at multiple angles. Performance indicators include compensation amount (e.g., ±50mm), working pressure (e.g., PN1.6MPa), and fatigue life (e.g., 1000 cycles).

Application Scenarios: Widely used in heating networks (steam pipelines), petrochemicals (reactor connections), power generation (boiler flues), metallurgy (blast furnace gas pipelines), and other fields. For example, in steam pipelines, every 100 meters of carbon steel pipe expands approximately 120mm when heated to 100°C, necessitating the installation of expansion joints to prevent deformation and damage.

Selection Considerations: The corrugated material (e.g., 316L stainless steel), number of layers (single/multi-layer), and connection method (flange/welding) must be selected based on the medium (corrosiveness, temperature), displacement type (axial/lateral), pressure rating, and installation space. During installation, attention must be paid to pre-tensioning (cold tightening) and the installation of guide supports to prevent instability.