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Problem of Deterioration of Lubricating Oil

April 28,2017.

   Machinery and equipment work, the oil due to long-term contact with the metal, by the surrounding air, temperature, pressure, electric field, light and other factors, in the oil gradually increased the external impurities, the results in the oil will be water, Sand, metal crumbs, and in the long-term use of gradual oxidation, making the chemical composition has changed, resulting in deterioration and harmful impurities, generally have the following categories:


  1. Fouled by foreign matter

    Oil in the use of the system, the most vulnerable to a variety of mechanical impurities dirty. These impurities are metal scrap, dust, sand, fiber material and so on. This is due to friction on the mechanical parts of the metal powder falling into the oil, or because the system and the machine shell closed lax, so that dust, sand into the oil. For example, when the tractor works in the field, the car on the road when driving, there will be a lot of small dust, sand with air through the air filter into the engine lubricants. Mine machinery is often soiled with ore powder. The hydraulic oil used in the processing of machine tools and hydraulic equipment is often defaced by the chip ends of the finished parts and other metal powders. These impurities have a bad effect on the quality of the system oil, it will like the same as the abrasive mechanical heat, so that the machine wears prematurely.


  2. Was cloudy

    Oil works in machinery and equipment, often water infiltration, which is due to a variety of mechanical equipment lubrication system, hydraulic drive system, or water cooling device is not tight enough, so that water into the oil. In addition, the moisture contained in the air can also be absorbed by the oil, because the oil has water absorption, its water absorption by the ambient temperature of the decision. For example, the transformer dissolved water and transformer oil temperature has a great relationship. From Table 1-1, we can see the relationship between the two.

  Table 1-1 Transformer oil moisture content and temperature

   Oil temperature / water content (mass fraction)

            5 0.011%

           25 0.042%

           50 0.054%

           75 0.105%


Lubricating oil

 3. Thermal decomposition

       There are many kinds of oil which, when in contact with the high temperature parts of the mechanical equipment, for example, in direct contact with the red metal during quenching in the combustion zone of the engine fuel and in direct contact with the high voltage arc in the oil switch , It will suffer a great local overheating, until the occurrence of part of the burning phenomenon, and can make the oil to a very high temperature. At this time the oil causes thermal decomposition (cracking), the result will produce glial and hard coke, which is called coke. Coke on the car engine has a great harm, because the coke is hot bad conductor, the combustion chamber wall and the piston roof covered with carbon deposition, causing poor heat dissipation, resulting in mechanical parts overheating and destruction and other accidents.


  4. Oxidation

        System oil in the course of the use of chemical changes in the main reason is the role of oxygen in the air. When the oil is working in the equipment, the degree of oxidation of the oil is accelerated and deepened as the oil temperature increases, the contact time increases, the contact area increases, and the air contact pressure increases. The results of the oxidation of the oil to produce some harmful substances, such as acids, gum, asphalt and so on. As the oil oxide continues to increase, causing the oil color darker, viscosity increases, acid value increases. Oil appeared in the sediment-like sludge, so the oil impurity content has increased. Oxygen oxidation often causes malfunction to the system.


  5. Diluted by fuel oil

     Car tractors lubricants and aviation lubricants, in a variety of internal combustion engine work process, because part of the fuel oil (diesel, gasoline) is not completely burning and seepage into the lubricating oil, and gradually diluted oil.


     The extent to which the lubricating oil is diluted by the fuel oil is related to the structure and working conditions of the engine and the type of fuel oil. In the waste aviation lubricants, with an average of 2% to 3% of the aviation gasoline, in the waste lubricants, the average containing 10% to 15% of the vehicle gasoline, tractor lubricants in the average containing 30% to 50% Tractor kerosene. Thus, if the engine uses the higher the fuel oil flash point, the amount of fuel oil that is infiltrated into the lubricating oil is also increased, and the lubricating oil becomes more dilute. This will make the oil flash point and viscosity are reduced, and lose the proper lubrication performance.


Change the cause of the change due to the effect of oxygen and other gases

So that oil oxidation deterioration, viscosity, acid value, corrosive substances, sludge increased, darker color; also produce bubbles, resulting in holes, cavitation


  The effect of influent oil emulsification, turbidity, increased viscosity, enhanced corrosion, reduced lubricity, additive hydrolysis, decreased insulation performance, oil oxidation to speed up the cracking, anti-foam agent settling, other additives are gradually consumed The effects of solid impurities such as colloidal, oil-borne, oxidized, asbestos, etc., are reduced by the various properties improved by the additive, the loss of dust, the wear of metal particles, the incomplete combustion of the oil,


   Accelerated oil oxidation, viscosity, acid value, increased mechanical impurities, darkened color, and even black, reduced lubricity, increased wear, filter and oil clogging, anti-foaming, anti-emulsifying, electrical insulation


High temperature effects

  Oil oxidation accelerated, viscosity, acid value, flash point rise, the evaporation of light components in the oil to speed up the accelerated decomposition of oil and additives, the use of reduced performance

Shear, agitation and other mechanical effects


  The viscosity is reduced, the viscosity and viscosity indices decrease, and the oxidation of the oil accelerates the light, the effects of γ-rays and other rays to promote oil oxidation, viscosity, acid value,


   The amount of bad impurities produced by the oil in the system is not allowed to increase indefinitely. When it reaches a certain level, the system can’t meet the requirements of the oil, so the oil becomes a scrap oil and needs to be replaced. If you do not replace, continue to use, it will speed up the wear and tear of moving parts, and the system failure, and reduce the service life of the equipment.


  How to determine whether the oil should be scrapped, this is a more complex problem, because the use of different conditions, a variety of mechanical equipment on the oil requirements of different needs to be combined with the actual use of the situation. Here only the general indicators are listed as criteria for judging scrap oil.


   ACORE VLF Lubricating Oil Purifier can improve the quality of used oil and recover the bad oil to new. The purified oil can be reused in industrial machinery.

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