As the core power equipment in industrial production, screw air compressors play a crucial role in ensuring production efficiency and cost control. However, issues often arise due to improper operation, lack of maintenance, or aging components. This article consolidates industry technical manuals and front-line maintenance experience to help quickly identify and resolve common faults in screw air compressors, minimizing downtime and reducing operational losses.
1. Startup and Shutdown Failures
1.1 Unable to Start
Phenomenon: The equipment does not respond after pressing the start button, and the operation indicator light does not illuminate.
Causes and Treatment:
- Power Supply Abnormality: Check if the fuse is blown (replace with the same specification fuse) and whether the voltage is stable (ensure it’s within 380V ±5%).
- Motor Failure: Rotate the rotor manually. If it’s stuck, replace the main unit. If there’s a short circuit or open circuit in the motor winding, professional maintenance is required.
- Control Circuit Failure: Inspect for poor contact at the start button (clean the contacts or replace the button) and for aging relays (replace with the same model).
1.2 Tripping and Shutdown During Operation
Phenomenon: The equipment loses power during operation, and the thermal relay is triggered.
Causes and Treatment:
- Voltage Fluctuation: Install a voltage stabilizer or adjust the transformer output.
- Excessive Exhaust Pressure: Check and calibrate the pressure switch setting (recommended pressure tolerance: rated pressure ±0.1MPa).
- Poor Lubrication: Replace with lubricating oil that meets the ISO VG32 standard and clean any clogged oil filters.
2. Performance Abnormalities
2.1 Excessive Exhaust Temperature (＞100℃)
Causes and Treatment:
- Cooling System Failure: Clean the oil cooler fins (use alkaline cleaning agents every 2000 hours) and check for damage to the cooling fan (replace with a motor of the same power).
- Lubricating Oil Problems: Refill oil to the center line of the sight glass (avoid mixing different brands of oil), and replace deteriorated oil (normal oil life: 2000-4000 hours).
- Temperature Control Valve Failure: Disassemble the valve body, clean the spring chamber, and replace the valve core if it’s stuck.
2.2 Insufficient Exhaust Pressure
Causes and Treatment:
- Intake Valve Stuck: Disassemble and clean the valve plate to remove carbon deposits (use kerosene for soaking and wiping). Check for broken cylinder diaphragms and replace with oil-resistant rubber diaphragms.
- Minimum Pressure Valve Failure: Test the valve core sealing (normal opening pressure: 4.5-5.0 bar), grind the sealing surface, or replace the assembly.
- Oil Separator Core Blockage: If the pressure difference exceeds 0.1 MPa, replace the filter element with original parts.
3. Oil System Failures
3.1 Abnormal Increase in Fuel Consumption
Phenomenon: The oil content in the compressed air exceeds the standard (>3ppm), and the oil level drops too quickly.
Causes and Treatment:
- Oil Return Pipe Blockage: Clean the oil return pipe (pay special attention to the U-shaped elbow) and replace the faulty one-way valve.
- Oil Separator Core Damage: Check for a sudden drop in pressure difference (normal difference: 0.2-0.5 MPa) and replace the oil separator core with high-quality, glass fiber-coated parts.
- Oil Emulsification: Ensure frequent condensate discharge (recommended every 8 hours), and install a high-efficiency gas-water separator.
3.2 Lubricating Oil Foaming
Causes and Treatment:
- Low Oil Temperature: Adjust the thermal control valve setting to maintain oil temperature at 80-90℃. Avoid operating in ambient temperatures below 5℃.
- Oil Filter Blockage: Replace the filter element when the pressure difference exceeds 1.5 bar (mandatory maintenance at 500 hours).
4. Electrical and Control System Failures
4.1 Frequent Loading and Unloading
Phenomenon: Pressure fluctuates frequently around the set value (e.g., 6.0-7.0 bar cycle).
Causes and Treatment:
- Pipeline Leakage: Use soapy water to check the sealing of joints, particularly around flange gaskets.
- Pressure Sensor Drift: Calibrate the sensor (acceptable error: <±1%) and replace damp or aging probes.
- Capacity Control Valve Failure: Clean carbon deposits from the valve core (avoid using wire brushes) and check the proportional coil resistance (normal range: 15-20Ω).
4.2 Motor Overload
Causes and Treatment:
- Belt Slippage: Adjust the tension (press down 5-10mm), and replace cracked belts.
- Rotor Carbon Deposition: Use a specialized cleaning agent to flush the main engine (recommended every 8000 hours).
5. Preventive Maintenance Recommendations
5.1 Daily Inspection
- Record parameters like oil level, exhaust temperature, and pressure fluctuation.
- Clean the radiator dust in a timely manner to ensure proper cooling.
5.2 Regular Maintenance
- Every 500 Hours: Replace air and oil filters, check coupling alignment.
- Every 2000 Hours: Replace lubricating oil and oil separator, calibrate the pressure sensor.
5.3 Environmental Management
- Keep the machine room well-ventilated (temperature <40℃).
- Install a pre-filter device to reduce dust intake, ensuring better air quality.
Conclusion
Most screw air compressor failures are a result of inadequate daily maintenance. Scientific inspections and standardized maintenance can greatly reduce failure rates and prolong equipment lifespan. For more complex issues (such as abnormal noises or current surges), it’s advisable to contact a professional service provider for diagnosis to avoid unnecessary disassembly and potential secondary damage. By adhering to regular maintenance schedules, troubleshooting effectively, and ensuring optimal operating conditions, screw air compressors can perform at their best, ensuring reliable production and cost-effective operation.
