Reasons for the blackening of lubricant color
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The lubricant we use is BP 46#, which is applied to the hot oil pump in the extrusion unit. However, after being used for a while, the lubricant in this pump turns black, taking on a color similar to that of soy sauce (within less than 30 days). The pump operates normally, and all the analysis results are within the standard ranges: viscosity: 44.6, contaminants: 0.03, flash point: 235, acid value: 0.14
The machine impurities should be above the limit. Color change is usually due to oxidation, the presence of contaminants, or the infiltration of other substances
Excessive mechanical impurities indicate wear or the presence of contaminants from other sources; a ferrography analysis can be performed. The significant change in the oil’s color may be due to oxidation at high temperatures. Perhaps the oil was not completely replaced the last time, and after new oil was added, the remaining old oil mixed together again once the machine was started up.
Machine impurities of 0.03 are within the acceptable range
Machine impurities of 0.03 are within the acceptable range
I feel that high temperatures make it easier to get darker skin. What is the highest temperature that the oil temperature or the temperature at the lubrication points has ever reached?
If a device has been in use for a long time, when replacing the lubricating oil it is necessary to remove any carbon deposits, or to rinse it with new oil. The oil filter element must be cleaned thoroughly before being reinstalled, the used oil should be drained, and then new oil should be added
High oil temperature caused by problems in the operation of the equipment is usually a sign of abnormalities during operation; for example, an increase in motor current, or noises coming from the bearings or gear meshings inside the equipment (a small gap between the gears can lead to rapid temperature rise). Mechanical issues require that maintenance personnel assess them on-site.
For the lubricants used in our factory, the lowest requirement for machine impurities is 0.01 for air compressor oil, while the other types require 0.007
Color change is usually caused by high-temperature oxidation, the intrusion of contaminants, or the penetration of other substances.