Discuss several common misunderstandings in the work of air compressor lubricating oil
Misunderstanding 1: Unit lubrication is refueling
Lubrication itself is a very profound theory. At present, few people can fully explain this field. It is comprehensive and involves basic theories such as fluid mechanics, solid mechanics, materials science, applied mathematics, and physical chemistry to discuss the principles and materials of lubrication. and ways to suppress harmful friction and wear. Refueling is only a small part of equipment lubrication. For example, for an air compressor unit, the lubrication process is involved in the whole process from the design stage of the unit to the entire life cycle of the unit’s use, maintenance, and scrapping. When lubricating oil is added between two friction gear surfaces, an oil film is formed to avoid direct contact between the gear friction surfaces and reduce wear. However, considering that lubricating oil also has certain side effects, it is necessary to control the amount of refueling of the unit. When the temperature of the piston unit is low in winter, the viscosity of the lubricating oil before starting the machine is high. More lubricating oil will make the oil temperature rise slowly, and the oil temperature will be low, which will increase the resistance when the unit rotates, and the viscosity is relatively large, which will increase the starting torque of the motor. . Therefore, it is stipulated that generally it only needs to be filled to about half of the lubricating oil scale line.
Misunderstanding 2: Lubricants can be replaced with each other
Due to the different manufacturers of each air compressor unit, the types, labels and related raw materials of lubricating oil are different according to the working conditions of the equipment, working environment, friction surface, characteristics of selected material properties and different designed lubrication methods. For example, if the rotation speed is high, it is necessary to form a unit with strong oil wedging ability. When selecting oil, you should choose lubricating oil with low viscosity; if the unit area load on the friction surface of the unit is large, you should choose lubricating oil with high viscosity and good oiliness; When the ambient temperature is high, lubricating oil with high viscosity, high flash point and strong stability or high dropping point should be selected. The gap between the friction surfaces of the machine head of the unit is small, and products with low lubricating viscosity can be selected; the rougher the friction surface, the higher the viscosity of the selected lubricating oil, the smaller the working taper if the lubricating grease is selected; when the unit is in normal operation, the unit oil The temperature is generally as high as about 100 degrees Celsius, and a lubricating oil with a higher viscosity should be selected at this time. Lubricating oil cannot be replaced under normal circumstances. If it is replaced arbitrarily, it will cause the lubrication environment of the air compressor equipment to fail. Damage to the friction surface of the unit will inevitably cause damage to the nose. It is a pity that each manufacturer declares the irreplaceability of their lubricating oil with special purpose, but the actual physical and chemical indicators of lubricating oil are kept strictly confidential, which creates a sense of confusion and mystery for customers.
Misunderstanding 3: Lubricating oil turns black and deteriorates
Modern lubricating oils usually add various additives in appropriate amounts to improve their lubricating performance. It is normal for lubricating oils with detergent and dispersant ingredients to turn black shortly after use. We can’t judge that the lubricating oil has deteriorated, but choose to replace the lubricating oil easily. Therefore, when determining whether the lubricating oil has deteriorated, you can’t just look at the color, and use the feeling as the basis for judgment. Comprehensive analysis is required, and physical and chemical analysis of oil products can be carried out if conditions permit, so as to change oil according to quality.
Misunderstanding 4: Change oil rigidly according to the prescribed cycle
General manufacturers are divided into mineral lubricating oil and synthetic lubricating oil in the choice of lubricating oil. There are differences in the grades of oil change intervals stipulated in the manual, because of the differences in the actual operating conditions of the unit, such as the mine open-air environment and the clean room environment are completely different. Therefore, the oil change interval must be different. If the actual environmental conditions of the unit are worse than the climatic conditions stipulated by the unit, it is necessary to shorten the oil change interval or use a test to grasp the oil change interval, or choose a higher-grade lubricating oil.
Misunderstanding 5: The more oil, the better
Too little lubricating oil will cause insufficient oil supply, poor lubrication, and lead to mechanical accidents. Therefore, it is actually a misunderstanding to “prefer excess rather than lack” when refueling. In fact, the amount of lubricating oil should be added in an appropriate amount. Too much will increase the resistance of the unit and increase the driving power consumption of the unit. Cause poor lubrication and shorten the service life of the air compressor unit.
Misunderstanding 6: Lubricants with high viscosity are better than those with low viscosity
The high viscosity grade of lubricating oil will reduce the pumping performance and flow rate of the oil pump, and at the same time reduce the lubricating performance, washing performance and cooling and heat dissipation performance. Mechanical failures such as burning, shaft holding, and damage to the crank connecting rod.
Misunderstanding 7: Always change oil during maintenance
Ordinary maintenance personnel in the process of equipment maintenance, even if the problem is only a simple replacement of spare parts, even after the manufacturer’s after-sales maintenance personnel replace the spare parts, they have found that the lubrication has expired. It is recommended that the user replace the lubricating oil, but the user allows the unit to continue to use! Prolonged use of lubricating oil for a long time will inevitably lead to a decrease in the performance of the air compressor unit and an increase in the total maintenance cost.
Misunderstanding 8: Superstitious “designated oil”
Most units stipulate that only the lubricating oil specified by the manufacturer can be used. In fact, the recommended oil designed and specified by the unit manufacturer is only suitable for their test conditions at that time. The oil consumption indicators for general working conditions may not be suitable for actual working conditions. Such as foreign units, there will also be “acclimatization” phenomenon in China. This kind of misunderstanding will not only cause damage due to the fact that the unit manufacturer’s recommendation is out of touch with reality, but also users can only pay for lubricating oil products with mediocre quality but expensive prices.
Misunderstanding 9: Expensive oil is good oil
Some people think that if the price is expensive, it must be good oil, and it must be easy to use! There are many aspects to this statement. First of all, look at the use. For example, if the price of the lubricating oil selected by Party A is higher than that of Party B, its sales price will be higher than that of Party B, and the price for users will be higher, but the quality of the oil may not be better than that of Party B. Secondly, the choice of oil is not to see which oil has the best performance, but to see whether the lubricating oil is suitable for the working conditions. There are oil products that are suitable for working conditions, and choosing low-priced oil products can save costs for enterprises.
In short, lubrication is an important guarantee for the normal operation of mechanical equipment. The selection of lubricating oil for air compressor units depends on the brand and model, and the operating conditions and environment of the unit should be considered comprehensively. The key is for the user to check this well.