Nangang Single-Screw Oil-Free Water-Lubricated Air Compressor Maintenance

Equipment Overview and the Importance of Maintenance

Single-screw oil-free water-lubricated air compressors, owing to their simple structure, clean discharge, and smooth operation, are widely used in industries with stringent air quality requirements, such as food processing, healthcare, and electronics. These units use water as both the sealing and lubricating medium, completely eliminating the risk of oil‑air contamination inherent in conventional oil‑lubricated systems. However, water quality management, rotor wear monitoring, and the stability of the water circulation system directly determine the unit’s service life and the quality of the supplied air; therefore, establishing a robust maintenance regime is essential.

Detailed Explanation of Core Maintenance Items

• Waterway Systems and Water Quality Management:Regularly test the conductivity, hardness, and pH of make-up water to prevent scaling or corrosion in internal flow paths. Clean the cooler’s heat exchange tubing and filters to prevent impurities from causing blockages and poor heat dissipation.
• Rotor and Seal Assembly Inspection:The single-screw compressor relies on elastomeric seals to achieve air–water isolation. The seals must be inspected and replaced periodically based on operating time to address wear, and aged or deformed components should be promptly replaced to maintain the compression chamber’s airtightness.
• Electrical and Control Unit Verification:Inspect the contactor contacts, motor insulation resistance, and sensor accuracy. Calibrate the pressure, temperature, and flow monitoring modules to ensure that automatic start/stop and protection logic operate correctly.
• Air-Water Separator and Aftertreatment:Drain accumulated water from the cyclone separator vessel and check the saturation level of the demister element. If a drying filter assembly is installed, also record pressure differential changes and replace consumables on schedule.

Maintenance Cycles and Operating Procedures

Routine inspections should focus on fluctuations in operating parameters, unusual noises, and signs of leakage, with inlet water temperature, discharge pressure, and current values recorded each shift. First-level maintenance is typically performed after a cumulative 500 to 800 hours of operation, emphasizing replacement of circulating water, cleaning of pipeline filters, and tightening of mechanical connections. Second-level comprehensive maintenance is recommended every 2,000 hours and includes disassembly and overhaul of the main unit, bearing clearance measurements, and backup of control system data. All operations must follow the procedures outlined in the equipment’s technical manual, and components may only be removed after power has been disconnected and pressure relieved.

Common Troubleshooting Recommendations

• High exhaust temperature:This is often caused by scaling in the cooling water channels or insufficient water flow. First, clean the heat exchanger and check the pump’s operating condition and the opening of the make-up water valve.
• Reduced output or unstable pressure:This is usually caused by worn seals, a clogged air filter, or stuck valves. Check the air circuit for blockages and verify the rotor clearance.
• Increased abnormal noise or vibration:This may be due to premature bearing failure, misalignment of the coupling, or loose foundation bolts. After shutdown, manually turn the shaft to check the resistance distribution, and recalibrate the drive system if necessary.

Safety Precautions

Before performing maintenance, the main power supply must be disconnected and any residual system pressure released; live work is strictly prohibited. Protective gloves must be worn when handling water‑side components to prevent frostbite from cryogenic liquids or burns from high‑temperature steam. Waste circulating water shall be collected centrally in accordance with environmental regulations and must not be discharged directly into the general drainage network. It is recommended to equip dedicated testing tools and standard‑size spare parts to improve repair accuracy and reduce the risk of secondary failures.