If the air compressor oil is deteriorated and replaced, it will accelerate the wear of parts, affect the service life and even cause safety accidents. Therefore, it is very important to check whether the lubricating oil is deteriorated and replace it in time.

　　Simple identification can be made by the following methods:

　　Oil flow observation method:

　　Take two measuring cups, one for the air compressor oil to be inspected, and the other for the table top. Lift the measuring cup full of lubricating oil 30-40cm away from the table top and tilt it to let it flow into the empty cup slowly. Observe the flow situation. When the lubricating oil with good quality flows, it should be long, thin, uniform and continuous. If the oil flow is fast or slow, sometimes there is a large flow, say The exposed oil has deteriorated.

　　Hand twisting method:

　　Twist the air compressor oil between thumb and index finger and grind it repeatedly. If the hand feels lubricity, less wear debris and no friction, and if there is a large friction feeling such as sand grains between fingers, it indicates that there are many impurities in the compressor oil, which can not be reused, the compressor oil should be replaced with a new one.

　　Illumination method:

　　On a sunny day, use a screwdriver to lift up the air compressor oil at a 45 degree angle with the horizontal surface. Compare with the sunlight and observe the oil drop. Under the light, it is good to see that there is no debris in the oil. It can continue to work. If there are too many debris, it should be replaced.

　　Oil drop trace method:

　　Take a clean white filter paper and drop a few drops of oil on the filter paper. After the pressure oil leaks, if there is black powder on the surface and there is a sense of astringency when touching it with hand, it means that there are many impurities in the lubricating oil. The good lubricating oil has no powder, and it is dry and smooth by hand, and it shows yellow trace.