Answer: In general, the oil of the operating air compressor should be sampled regularly to observe the oil color and cleanliness, and regularly analyze the physical and chemical properties of the oil such as viscosity, acid value, and n-pentane insoluble matter. If any of the following conditions occur, oil replacement should be considered:
(1) Water content is greater than 0.1%.
(2) Acid value is greater than 2 mg KOH/g.
(3) Kinematic viscosity changes by more than ±10% of the allowable value.
(4) Color changes to brown-black.
Each air compressor manufacturer has strict regulations on the replacement cycle of lubricating oil, but the replacement cycle is not the same and the replacement conditions are slightly different. If conditions permit, users can use regular sampling inspections to compare the above conditions to determine whether the lubricating oil needs to be replaced.
