Typical Fault of Screw Air Compressor – Excessive Oil Consumption
2026-01-06Visits: 190 +
In industrial production scenarios, screw air compressors have become the core equipment of compressed air systems due to their stable air production efficiency and low operational costs. Excessive oil consumption is a high-frequency fault during the operation of screw compressors. It not only increases the cost of lubricating oil but also pollutes the compressed air, clogs post-filters, and even affects the normal operation of downstream equipment. Based on field operation and maintenance experience, this article summarizes the core causes of excessive oil consumption and provides a step-by-step troubleshooting plan, offering practical guidance for frontline technicians.Step 1: Check the operating condition of the oil-gas separator.The oil-gas separator is the core component that controls the oil content in the compressed air. Its failure can directly lead to a sharp increase in oil consumption. First, observe the service time of the separator. If it exceeds the manufacturer's recommended replacement cycle of 2,000–3,000 hours, the filter element may lose its separation efficiency due to clogging or damage. Next, disassemble and inspect the surface of the filter element. If there are obvious tears, holes, or excessive oil accumulation at the bottom, it should be replaced immediately. Additionally, pay attention to the installation seal of the oil-gas separator. If the sealing gaskets of the upper and lower flanges age or deform, unseparated oil-gas mixture may leak directly through the gaps, creating the illusion of high oil consumption.Step 2: Check the pressure and liquid level parameters of the oil-gas tank.The pressure difference inside the oil-gas tank is key to ensuring effective oil-gas separation. During normal operation, the pressure in the tank should remain within the rated range. If the pressure is too high, oil mist particles cannot settle effectively; if the pressure is too low, the lubricating oil circulates too quickly, leaving insufficient time for proper separation. At the same time, check the oil level gauge. If the oil level exceeds the upper limit mark, lubricating oil will be discharged directly with the compressed air. If the oil level is below the lower limit, it may cause the machine to overheat, indirectly increasing oil consumption. It is recommended to check the oil level after the compressor has been shut down and depressurized, ensuring it remains within the safe range between the upper and lower limits.Step 3: Verify the operating status of the temperature control valve and cooling system.The temperature control valve regulates the temperature of the lubricating oil. If the valve is stuck in the closed position, the oil cannot flow into the cooler for cooling, causing the oil temperature to rise continuously. In a high-temperature environment, the viscosity of the lubricating oil decreases, and atomization increases, making it difficult for the oil-gas separator to capture all oil mist particles, ultimately leading to excessive oil consumption. At this point, the oil temperature should be measured. The normal operating oil temperature should be between 75°C and 95°C. If it exceeds this range, disassemble the temperature control valve to clean the valve core or replace the faulty temperature control component. Also, check whether the cooler is clogged with dirt to ensure the heat dissipation channel is clear.Step 4: Check the unobstructed flow of the oil return pipe and check valve.The lubricating oil separated by the oil-gas separator needs to return to the main unit through the oil return pipe for recirculation. If the oil return pipe is bent or blocked, or if the check valve is stuck or faulty, the separated oil cannot return in time, accumulating in the separator and being discharged with the compressed air. During troubleshooting, after shutting down the compressor, remove the oil return pipe and perform a blow test. If the airflow is obstructed, clean the pipeline. Check the flexibility of the check valve's opening and closing, and replace any faulty check valves promptly.Step 5: Verify the operating condition and component wear of the main unit.If the above checks show no abnormalities, internal faults of the main unit should be considered. Wear of the bearings of the screw compressor's male and female rotors, aging and leakage of shaft seals, can cause lubricating oil to directly enter the compression chamber and be discharged with the gas. If the rotor clearance is too large, compression efficiency decreases, oil temperature rises, and oil consumption increases indirectly. At this point, measure the vibration and noise levels of the main unit. If abnormal sounds are detected, shut down the machine, disassemble it, and inspect the bearings, shaft seals, and rotor clearance. A major overhaul may be necessary if required.The troubleshooting of excessive oil consumption in screw air compressors should follow the principle of "from easy to difficult, from surface to core," prioritizing the inspection of consumables and vulnerable parts before delving into core components. In daily operation and maintenance, it is recommended to establish a regular inspection system, replace consumables such as oil-gas separators and lubricating oil on time, and monitor key parameters like oil level and oil temperature to reduce the probability of excessive oil consumption from the source, ensuring the stable and efficient operation of the air compressor.
