The bidirectional sleeve compensator is a key component in pipeline systems used to absorb thermal expansion and contraction or displacement in other directions, and is particularly suitable for applications that require bidirectional compensation.
1. Basic structure and working principle
Structural composition
Inner and outer sleeves: The inner sleeve is connected to the pipe and can slide along the axial direction. The outer sleeve is fixed to the casing or another section of the pipe.
Sealing device: Usually, graphite rings, rubber rings or combined seals are adopted to ensure the sealing performance during sliding.
Guide support: Prevents lateral displacement and ensures smooth axial movement.
Limit structure: Prevents excessive compression or stretching and protects the compensator.
Working principle: Through the relative sliding of the inner and outer sleeves, it absorbs the bidirectional axial displacement (compression and tension) of the pipeline.
2. Core features
Bidirectional compensation capacity: It can simultaneously absorb the thermal expansion (thrust) and cold contraction (tension) of the pipeline.
High pressure resistance performance: The design pressure can usually reach over 1.6MPa, making it suitable for high-pressure pipelines.
Low coefficient of friction: Lubricated with polytetrafluoroethylene (PTFE) or graphite to reduce sliding resistance.
Long service life: High-quality materials (such as carbon steel and stainless steel) and sealing technology extend the service life.
3. Main types
Ordinary bidirectional type: Standard design, suitable for general temperature and pressure conditions.
Bidirectional injection type: By injecting sealing packing (such as flexible graphite), the sealing performance is enhanced, making it suitable for high temperature and high pressure.
Spherical bidirectional compensator: Combined with the rotation function, it can compensate for a small amount of angular displacement.
4. Application scenarios
Thermal expansion compensation for steam and hot water pipelines in thermal network networks.
Petrochemical/Energy: High-temperature oil and gas pipelines, chemical plant pipelines.
District heating: Compensation between fixed supports in long-distance heating networks.
Building pipelines: Air conditioning water systems and fire protection pipelines for high-rise buildings.
5. Key points for selection
Displacement: Calculate the maximum axial displacement based on the temperature difference of the pipeline (ΔL = α × L × ΔT).
Pressure rating: Match the working pressure of the system and take into account the safety margin.
Temperature range: The sealing material needs to withstand the temperature of the medium (for example, graphite can withstand a temperature of up to 600℃).
Connection method: Flange connection (commonly used) or welded end.
6. Installation precautions
Alignment: Ensure that the compensator is aligned with the pipe axis to avoid uneven loading.
Guide supports: Guide supports are installed on both sides, with a spacing not exceeding 4 times the pipe diameter.
Pre-stretching/compression: Adjust the initial position according to the installation temperature (such as pre-stretching 50% displacement in cold state).
Anti-corrosion: It is recommended to apply an additional anti-corrosion coating or insulation layer when installed outdoors.