In equipment maintenance, it is often necessary to judge the quality of lubricating oil and grease, as well as its influence on the movement of equipment and the cause of failure. It is obviously necessary to adopt some simple identification methods when there is no conditional analysis and testing.Simple Identification of Lubricating Oil and Grease
(1) Viscosity inspection: generally, the lubricating oil used by the equipment and the lubricating oil with standard viscosity required by the equipment are inspected by comparison to determine whether the oil needs to be changed Breaing.
1) On a clean glass, drop a drop of lubricating oil to be inspected and standard lubricating oil respectively. Put the glass flat when dripping oil. After dripping the oil, tilt the glass, and pay attention to comparing the speed and distance of the oil dripping down. If the flow velocity is large and the flow distance is long, the viscosity is relatively small. If the speed is roughly the same and the flow distance is close, the viscosity grade of this oil may be the same or close.Simple Identification of Lubricating Oil and Grease
2) Use two glass test tubes with the same diameter and length. One is filled with the lubricant to be inspected and the other is filled with standard lubricating oil. The oil in the two test tubes shall be installed at the same height and shall not be full, leaving a bubble. Simple Identification of Lubricating Oil and Grease
Then block the test tube mouth with a wooden plug, connect the two test tubes together, invert the speed 180 degrees at the same time, and observe the rising speed of bubbles in the test tube. The test tube with fast bubble rising speed is filled with lubricating oil, and the viscosity is relatively small; The lubricating oil that can be loaded into the test tube with slow bubble rise speed has relatively high viscosity.Simple Identification of Lubricating Oil and Grease
If you want to judge which brand of oil to be inspected is close to, you can use several known brands of oil to compare with the oil to be inspected. When the bubble rising speed of the two oils is close, the quality of the two oils is close in terms of viscosity.Simple Identification of Lubricating Oil and Grease
(2) Moisture test
1) Put the oil to be tested into a dry test tube, then heat it at the bottom of the test tube to about 100 ~ 120 degrees, and observe while heating. If water is present in the oil, it will cause noise, foam, or condensation of water on the test wall, and the turbidity of the oil.Simple Identification of Lubricating Oil and Grease
2) Put the oil to be tested into the test tube, and then add a small amount of white powdered anhydrous crystalline copper sulfate. If there is water in the oil, it will immediately turn blue and precipitate at the bottom of the test tube.Simple Identification of Lubricating Oil and Grease
3) Dip the clean and dry veil into the oil to be tested and ignite it with fire. If there is water in the oil, explosion sound or flash will occur.Simple Identification of Lubricating Oil and Grease
(3) Inspection of mechanical impurities
1) The oil with low viscosity can be directly injected into the test tube, heated a little and observed statically. If you see sediment or suspended solids, there is mechanical precipitation in the oil.
2) The oil with high viscosity can be diluted 5 ~ 10 times with clean gasoline and identified according to the above method. It can also be diluted and filtered with filter paper. If it is made of mechanical impurities, it will be retained on the filter paper.Simple Identification of Lubricating Oil and Grease
2. Simple identification of lubricating grease
Whether there are impurities in the maintenance of the equipment depends on whether there are changes in the quality of the mixed grease and whether there are main impurities in the maintenance process.
(1) Identification of whether the lubricating grease fiber network structure is damaged: if the lubricating grease fiber network structure is damaged, it is de adhesion, which reduces the lubricating performance.Simple Identification of Lubricating Oil and Grease
During identification, the lubricating grease can be coated on a clean copper sheet, and then put into a large mouth container filled with water for rotation. After repeated rotation, if oil droplets appear on the water surface, it indicates that the fiber network structure of the tested grease has been damaged. Obviously, this method is only suitable for the identification of water-resistant grease.
(2) Identification of water resistance: when using grease, if you don’t know the water resistance, you can take a small amount of grease with your fingers, drop a little water and twist it slightly. If the tested grease is emulsified rapidly, it can be judged as sodium base grease. If there is no emulsification, it can be judged to be calcium base grease, lithium base grease or barium base grease. If the emulsification is slow and incomplete, it can be judged to be calcium sodium base grease.
(3) Identification of impurities
1) Take a little grease with your fingers for twisting and pressing, and judge whether there are hard particles in the tested grease by feeling.
2) Apply the lubricant evenly on the clean glass sheet, scrape the thickness of the coating to about 0.5mm, and place it in the light for observation to judge whether there are particle impurities in the tested grease.
3) Put a small amount of fat in the test tube, add gasoline to dissolve it, and observe whether there is precipitation.
4) Identification of oxidation deterioration: the grease with oxidation deterioration can be seen clearly from the appearance. At this time, the color of the grease becomes black or deepened, and a hard adhesive film will be formed on the surface.