How to Maintain Oil-Free Air Compressors to Extend Service Life
Oil-free air compressors require periodic inspection and maintenance after a period of operation. Regular procedures ranging from startup, operation, inspection, to scheduled component maintenance and repair help prolong the service life of oil-free air compressors. Key precautions are elaborated below.
I. Methods to Extend the Service Life of Oil-Free Air Compressors
First, follow the operating procedures for oil-free air compressors. Most shutdown procedures are the reverse of startup procedures. Gradually reduce the rotating speed to a low level, fully open the exhaust bypass valve, completely close the exhaust valve, shut down the driver, and confirm that the entire air compressor unit automatically stops step by step. Do not cut off cooling water supply within 30 minutes after equipment shutdown.
Second, after operating the oil-free air compressor, inspect all stage valve components and check the fit between valve plates and valve seats. Replace valve plates with cracks using spare parts. Inspect front covers of cylinders at all stages and check friction traces on cylinder liners; identify root causes if scratch marks exist. Check friction conditions between crosshead slippers and guide rails on the unit frame. Remove connecting rod big-end bushings and crosshead pins, then inspect wear on friction surfaces.
In addition, verify whether the oil level indicated by the oil level gauge of the oil-free air compressor meets requirements. Check tightness of all connecting fasteners; retighten any loose connections. Observe and confirm flexible movement of moving parts. Rotate the flywheel by hand to crank the oil-free air compressor two or three revolutions to detect jamming or collision.
Next, inspect the quality of compressor lubricating oil and replace the lubricant inside the unit. After initial operation of the oil-free air compressor, a large amount of fine metal powder mixes into the lubricant due to component running-in and oil cleaning effects. Therefore, all lubricating oil shall be replaced after 24 hours of operation. Replace the oil again after 200 operating hours. After these two oil changes, follow routine maintenance cycles for subsequent oil replacement.
Maintenance of Key Components of Oil-Free Air Compressors
Before repairing or replacing any components as specified below, confirm the following prerequisites:
All pressure inside the oil-free air compressor system has been relieved; the system is isolated from other pressure sources; the main circuit switch is disconnected, and safety lockout tags prohibiting switch closure are posted.
The replacement interval of compressor lubricating oil depends on operating environment, humidity, dust concentration and whether acidic or alkaline gas exists in ambient air. For newly purchased oil-free silent air compressors, replace lubricating oil after the first 500 operating hours. Thereafter, replace oil every 4,000 operating hours. For units running less than 4,000 hours annually, perform oil replacement once every year.
The oil filter must be replaced after the first 300–500 hours of initial startup. Replace it again after 2,000 operating hours, and follow a 2,000-hour cycle for subsequent replacements.
Prevent foreign debris from falling into the compressor air end cavity when maintaining or replacing the air filter or intake valve. Seal the air end inlet during operation. After finishing maintenance, rotate the air end manually in its operating direction for several turns to confirm no obstruction before startup.
Inspect belt tension every approximately 2,000 operating hours. Adjust tension until the belt is properly tightened if loose. Protect the belt from oil contamination, which may cause premature belt failure.
Replace the oil filter simultaneously whenever changing lubricating oil.
I. Methods to Extend the Service Life of Oil-Free Air Compressors
First, follow the operating procedures for oil-free air compressors. Most shutdown procedures are the reverse of startup procedures. Gradually reduce the rotating speed to a low level, fully open the exhaust bypass valve, completely close the exhaust valve, shut down the driver, and confirm that the entire air compressor unit automatically stops step by step. Do not cut off cooling water supply within 30 minutes after equipment shutdown.
Second, after operating the oil-free air compressor, inspect all stage valve components and check the fit between valve plates and valve seats. Replace valve plates with cracks using spare parts. Inspect front covers of cylinders at all stages and check friction traces on cylinder liners; identify root causes if scratch marks exist. Check friction conditions between crosshead slippers and guide rails on the unit frame. Remove connecting rod big-end bushings and crosshead pins, then inspect wear on friction surfaces.
In addition, verify whether the oil level indicated by the oil level gauge of the oil-free air compressor meets requirements. Check tightness of all connecting fasteners; retighten any loose connections. Observe and confirm flexible movement of moving parts. Rotate the flywheel by hand to crank the oil-free air compressor two or three revolutions to detect jamming or collision.
Next, inspect the quality of compressor lubricating oil and replace the lubricant inside the unit. After initial operation of the oil-free air compressor, a large amount of fine metal powder mixes into the lubricant due to component running-in and oil cleaning effects. Therefore, all lubricating oil shall be replaced after 24 hours of operation. Replace the oil again after 200 operating hours. After these two oil changes, follow routine maintenance cycles for subsequent oil replacement.
Maintenance of Key Components of Oil-Free Air Compressors
Before repairing or replacing any components as specified below, confirm the following prerequisites:
All pressure inside the oil-free air compressor system has been relieved; the system is isolated from other pressure sources; the main circuit switch is disconnected, and safety lockout tags prohibiting switch closure are posted.
The replacement interval of compressor lubricating oil depends on operating environment, humidity, dust concentration and whether acidic or alkaline gas exists in ambient air. For newly purchased oil-free silent air compressors, replace lubricating oil after the first 500 operating hours. Thereafter, replace oil every 4,000 operating hours. For units running less than 4,000 hours annually, perform oil replacement once every year.
The oil filter must be replaced after the first 300–500 hours of initial startup. Replace it again after 2,000 operating hours, and follow a 2,000-hour cycle for subsequent replacements.
Prevent foreign debris from falling into the compressor air end cavity when maintaining or replacing the air filter or intake valve. Seal the air end inlet during operation. After finishing maintenance, rotate the air end manually in its operating direction for several turns to confirm no obstruction before startup.
Inspect belt tension every approximately 2,000 operating hours. Adjust tension until the belt is properly tightened if loose. Protect the belt from oil contamination, which may cause premature belt failure.
Replace the oil filter simultaneously whenever changing lubricating oil.
