Maintenance of Tongshan Single-Screw Oil-Free Water-Lubricated Air Compressors

Core Maintenance Principles

Oil-free water-lubricated single-screw compressors rely on pure water as the working fluid for sealing, cooling, and lubrication; their operational stability depends directly on water quality management and precise control of mechanical clearances. Routine maintenance should follow the principle of “water first, then machine, with periodic calibration” to prevent impurity buildup or dry friction that could damage the compressor unit.

Water Circuit System Maintenance

Water is the core working fluid for this type of equipment, and water hardness and cleanliness directly affect exhaust quality and component life. During maintenance, the following procedures should be prioritized:

• Water quality testingMonitor the influent pH (recommended to be maintained between 6.5 and 8.5) and conductivity weekly; if limits are exceeded, initiate blowdown immediately and replenish with treated water.
• Pipeline cleaning: Perform chemical descaling on the cooler, distribution valve, and sealing water passages every six months to prevent scale buildup from reducing heat transfer efficiency.
• Liquid Level Monitoring: Check the condition of the water tank and circulation pump, ensuring the water level remains within the specified range to prevent cavitation or insufficient water supply.

Inspection of the Main Rotor and Shaft Seal

The single-screw configuration consists of a main rotor and an idler screw, where a water film forms a dynamic seal. After prolonged operation, the following areas require attention:

• Clearance measurementUse feeler gauges to check the axial and radial clearances between the main rotor and the star gear; if these exceed the specified tolerances, adjust the shims to restore them to the standard values.
• Shaft seal status: Inspect the joint between the stationary and rotating rings for signs of leakage; if water stains are spreading, replace the wear-resistant sealing ring promptly to prevent external dust from entering.
• Star wheel wearAfter a shutdown and power failure, manually turn the shaft to inspect the star wheel groove for scoring or uneven wear. Minor wear can be repaired by polishing; severe deformation requires replacement of the entire assembly.

Filter and Cooling Assembly Maintenance

Efficient air–water separation and heat dissipation are critical to ensuring continuous operation. It is recommended to perform maintenance according to the following schedule:

• Air intake filter: Inspect the primary filter monthly for clogging, and replace the filter element when the pressure differential exceeds the set threshold to ensure adequate airflow.
• Gas–water separation assemblyReplace the separator filter element every two thousand hours or when pressure drop increases significantly to ensure the outlet air dew point meets specifications.
• Radiator Cleaning: Use dry compressed air to back-blow dust from the fins, and if necessary, soak them in a neutral cleaning agent to restore heat exchange performance.

Electrical and Control Unit Inspection

The control system is responsible for load regulation and protective shutdown; ensure wiring is secure and parameters are accurate.

• Sensor calibration: Verify the readings of pressure transmitters, temperature probes, and flow meters; recalibration is required if the deviation exceeds 2 percent.
• Contactors and Relays: After disconnecting the power supply, inspect the contacts for burnout, tighten the terminal block screws, and eliminate the risk of loose connections.
• Data RecordingExport historical operating curves to compare current fluctuations with exhaust temperature trends, enabling early identification of potential overload risks.

Standardized Maintenance Cycle Reference

Establishing a tiered maintenance plan can effectively extend the service life of the entire machine:

• Daily Inspection: Listen for abnormal sounds, check instrument readings, and confirm that the automatic drain valve is operating correctly.
• Monthly maintenanceClean the housing, check the tension of the drive components, and test the opening pressure of the safety valve.
• Annual OverhaulComplete disassembly of the main unit, replacement of all wear parts, flushing of internal flow passages, and re-verification of controller parameters.