The lubricating oil in most equipment lubrication systems (such as hydraulic systems, gearbox systems, turbine oil systems, paper machine circulating oil systems, oil film bearing oil systems, etc.) will be affected by air, moisture, particulate dust and equipment in the environment. It gradually deteriorates under the influence of heat generated by operation. The deterioration of equipment lubricants will come from the following reasons: 1. Oxidation The oxidation of lubricating oil is the reaction of lubricating oil molecules and oxygen molecules, which will lead to an increase in viscosity and the production of sediments such as sludge, additives will be depleted, and the Base Oil will also be decomposed. Once the lubricating oil starts to oxidize, its acid value will begin to rise. The presence of acid will cause the beginning of equipment corrosion.
2. Thermal cracking Temperature is a factor that needs to be paid attention to during the use of lubricating oil. No matter what kind of system, the lubricating oil will be affected by the operation of the equipment (friction, kinetic energy conversion, heat transfer) and increase the temperature. Once its temperature exceeds the temperature at which the oil can maintain a stable temperature, thermal cracking will occur and intensify.
3. Micro-deflagration (cavitation) When the tiny bubbles in the lubricating oil enter the high-pressure area from the low-pressure area, it will cause a micro-deflagration phenomenon, or cavitation, due to pressure changes. Microscopic deflagration will cause the oil around the small bubbles to be instantly heated and oxidized. The temperature of the bubble burst area can reach 1093 degrees Celsius (2000 degrees Fahrenheit). Violent micro-deflagration can make the equipment emit obvious noise and vibration.
4. Additive depletion The additives in most lubricating oils are continuously depleted as the lubricating oil deteriorates during the use of the lubricating oil. Oxidation, thermal cracking, hydrolysis and other pollution will cause the consumption of additives. 5. Pollution Dust, moisture and air can cause contamination of the lubricant and greatly aggravate the deterioration of the lubricant. Dust mixed with fine metal particles will become a catalyst that accelerates the deterioration of lubricants. This is why many equipment recommend the use of ashless hydraulic oil (use of anti-wear additives without zinc). What harm will the deterioration of equipment lubricating oil cause to equipment?
Continuing to use the deteriorated lubricating oil will undoubtedly be detrimental to the lubrication protection of the equipment. We have summarized the following 8 hazards:
1. The acidic substances generated by the oxidation and deterioration of the oil will corrode the metal contact surface;
2. Additives in the oil will be gradually consumed, resulting in a decrease in the thickness and strength of the lubricating oil film and increased mechanical wear;
3. Decreased oil lubrication, cooling and flow properties will accelerate metal surface fatigue;
4. Oil sludge will block the filter system, and related parts need to be cleaned or replaced;
5. Oil sludge will greatly shorten the service life of sealing and guiding materials;
6. Oxidized and dirty oil will affect the action of the valve, causing the valve to jam and the valve core to wear quickly;
7. The system response becomes slower and accompanied by irregular actions, and the pressure transmission performance of the hydraulic system is reduced;
8. The oxidized, emulsified, particulate and air-polluted oil will corrode oil pump parts due to cavitation, causing the oil pump moving parts to fail due to insufficient lubrication, and even burn the pump. Statistics show that 80-90% of hydraulic system failures are caused by pollution and deterioration of hydraulic oil. The situation of other types of equipment lubricating oil systems is similar. Solution: 1. Choose high-performance lubricant products Through the above analysis, we should know that the anti-oxidation performance, the use of non-zinc anti-wear additives, and the excellent air release performance of lubricants will definitely have better performance and anti-deterioration ability, and will naturally be able to work under the same environment and use conditions. Get better performance and achieve longer service life.
2. Clean the system and pre-filter before adding new oil The lubricating oil system of many large power plants and steel smelting enterprises will be carefully cleaned before the first oil filling. Special flushing oil is used to clean the dust and other foreign objects that may exist in the equipment system; before adding new lubricating oil, the oil The product (new oil, conventional cleanliness level 7-9) is filtered to reach a higher level of cleanliness (such as level 5-6) and then injected into the system.
3. Maintain good lubricating oil conditions First of all, it is necessary to avoid the deterioration of the purchased lubricating oil during the storage process. For example, storage in the open air, in the sun and rain, and the storage area is wet or close to the heat source, which will affect the quality of the oil.
4. Regularly sample and analyze the oil products in use Through the analysis of the oil samples of the oil in use, the data of its viscosity, acid value, water content, cleanliness, metal particles and other indicators can be obtained, and the operating conditions of the equipment and the lubricating oil can be analyzed by comparing with the corresponding indicators of the new oil. The degree of degradation.
5. Determine whether the oil needs to be replaced or filter maintenance according to the results of oil testing and analysis Poor lubricating oil (such as acid value, water content, and cleanliness exceeding the standard) will inevitably have a serious negative impact on the operation of the equipment or even cause failures and lead to production shutdown. When the oil is in poor condition, replacing the new oil is naturally the easiest and effective way. However, the replacement of new oil usually leads to a significant increase in the cost of lubricating oil purchase and waste oil disposal. Therefore, in many cases, we can consider filtering and maintaining equipment lubricating oil. Through fine filtering, its state indicators can be restored to a greater extent to ensure that it can continue to be used normally: (1) Remove the sludge and moisture in the lubricating oil in time, restore the state and significantly slow down the continued deterioration of the lubricating oil; (2) Avoid equipment operation failures caused by sludge accumulation; (3) Through low-cost lubricating oil filtration and maintenance, high-cost failures (shutdown) and equipment maintenance (replacement of pumps, valves, filter elements, etc.) are avoided.
