High-pressure Screw Air Compressor

A: Common faults of high-pressure screw compressors during long-term operation mainly include the following categories: Exhaust system faults: Excessively high or low exhaust pressure is a common problem. Excessively high exhaust pressure may be caused by poor condenser heat dissipation, air in the system, or excessive refrigerant charge; excessively low exhaust pressure may be related to insufficient refrigerant or low suction pressure. Abnormal temperature: Excessively high exhaust or oil temperature will accelerate lubricating oil coking, affecting lubrication, and in severe cases, may cause rotor seizure. Common causes include excessively high compression ratio, poor heat exchange in the oil cooler, and insufficient oil injection. Oil system problems: Oil circuit blockage, abnormal oil level, and oil contamination are relatively frequent faults. Under long-term high-temperature operation, the cooling lubricating oil is prone to deterioration, leading to scale buildup and blockage in the pipeline. Excessively high or low oil levels will affect the normal operation and lubrication effect of the compressor. Abnormal starting and operation: Failure to start, automatic shutdown, excessive vibration during operation, and abnormal noises also require close attention. Among them, mechanical problems such as loose foundation bolts, rotor imbalance, and bearing wear are often the root causes of vibration and abnormal noise.

A: Excessively high discharge temperatures in high-pressure screw compressors can stem from various factors: Excessive compression ratio: The system deviates from design operating conditions; excessively high condensing pressure or excessively low evaporating pressure can lead to an abnormal compression ratio. Poor oil cooler heat transfer: Dust accumulation on the cooler surface or internal scaling impairs heat dissipation efficiency. Insufficient oil injection: Blockages in the oil circuit or low oil pressure prevent the rotors from receiving adequate cooling and lubrication. Suction gas overheating: Excessive suction superheat or leakage through the bypass valve causes high-temperature gas to recirculate. Lubricating oil quality issues: Oil aging, deterioration, or improper viscosity selection reduces heat exchange capability. It is recommended to regularly inspect the cleanliness of the oil cooler, the operating status of the temperature control valve, and the quality of the lubricating oil to promptly address any abnormalities.

A: Proper routine maintenance is crucial for extending the service life of high-pressure screw compressors: Regularly replace the "three filters and one oil": The air filter, oil filter, oil-air separator, and lubricating oil must be replaced at scheduled intervals. Change the oil after the initial 500 hours of operation, and subsequently every 4,000 hours; replace the oil filter after the initial 300–500 hours, and subsequently every 2,000 hours. Clean the cooler: Remove dust from the cooler surface approximately every 2,000 hours of operation to ensure efficient heat dissipation. Do not use hard objects to scrape off dirt, as this could damage the cooling fins. Drain condensate: Moisture tends to condense inside the oil-air separator tank during humid weather or after the unit has shut down and cooled; drain this promptly to prevent the lubricating oil from emulsifying. Maintenance during prolonged shutdowns: During periods of inactivity, start the oil pump every 10 days to circulate the lubricating oil, and run the unit for one hour every 2–3 months to prevent moving parts from seizing.