I. Couplings for Compressor (used for equipment transmission)
Used to connect the compressor motor with the main unit (such as screw rotors, piston components, etc.), to transfer torque and compensate for installation errors. Main features are as follows:
1. Common types and structures
Elastic couplings: The most widely used, transmitting power through rubber or polyurethane elastomers, capable of absorbing vibrations, buffering impacts, and compensating for axial, radial, and angular deviations (such as thePlum blossom shape and claw-shaped elastic couplings commonly used in GA series screw machines).
Rigid couplings： Suitable for high-precision installation scenarios， without buffering capability， but with high transmission efficiency， allowing only minor deviations (less commonly used in conventional compressors， more often used in special conditions).
Diaphragm couplings： Using metal diaphragms as the elastic element， resistant to high temperatures and oil contamination， suitable for large compressors with high rotational speed and high torque， with strong compensation capacity and less maintenance.
2. Core functions
Precisely transfer the motor power to the compressor main unit， ensuring minimal energy loss.
Absorb vibrations and impacts during equipment operation， protecting precision components such as motors and bearings.
Compensate for coaxiality errors during installation (axial， radial， and angular)， avoiding additional stress.
3. Faults and maintenance
Common issues： Aging / breaking of elastomers (resulting in abnormal noise， increased vibration)， loose connecting bolts (causing eccentric operation)， fatigue cracks in diaphragms (more likely to occur under high load).
Maintenance points：
Regular inspection (every 1000-2000 hours)： Check if the elastomers are worn， if the bolts are tightened， and if the coupling has radial movement.
Replacement cycle： Elastomers usually replace every 2-3 years or as per the manual， while metal components with cracks need to be replaced immediately.
Installation requirements： After replacement， the coaxiality needs to be recalibrated (typically radial deviation ≤ 0.1mm， angular deviation ≤ 0.1°/m)， otherwise， it is prone to early wear of bearings.
II. Pipe couplings (used for system connection)
Used for connecting pipes such as compressor exhaust pipelines and cooling water pipelines， mainly to seal， compensate for pipeline displacement， and reduce vibration transmission.
1. Common types and applicable scenarios
Flexible pipe couplings：
Rubber expansion joints： Suitable for low-pressure gas or water pipelines， capable of compensating for displacement caused by thermal expansion and contraction of the pipeline， while absorbing vibrations and preventing stress concentration caused by rigid connection.
Metal bellows couplings： Suitable for high-temperature and high-pressure exhaust pipelines (such as main pipelines for compressed air)， with excellent temperature and pressure resistance， large compensation capacity， and good sealing performance.
Rigid pipe connectors： Such as flange connections (with sealing gaskets)， suitable for fixed pipeline sections， requiring strict coaxiality， without compensation capability.
2. Core functions
Ensure the airtightness / watertightness of the pipeline connection， preventing leakage of compressed air and cooling water.
Compensate for displacement caused by temperature changes (such as fluctuations in compressor exhaust temperature) or equipment vibration.
Block the transmission of equipment vibration to the pipeline system， avoiding pipeline resonance or fatigue fracture.
3. Maintenance points
Regular inspection of sealing surfaces for leakage (such as soap water testing)， aging and cracking of rubber parts， and corrosion or deformation of metal bellows.
Avoid excessive stretching or compression： The compensation capacity of flexible couplings is limited， exceeding the range will lead to premature damage.
Match with the medium： Exhaust pipelines need to use materials resistant to oil and high temperatures， and water pipelines need to consider rust and corrosion prevention.
