Is air harmful to lubricants and equipment?
author: Leila
2024-07-12
The lubrication system is a critical part of all kinds of machines, equipment and automobiles, and one of the main points of maintenance is not to bring in impurities. We generally pay attention to contaminants such as dust, particulate impurities, moisture, etc., and tend to overlook air - air? Yes, air does have an impact on the performance of lubricants. While it is inevitable that lubricants will come into contact with air, air mixed in with the lubricant, such as bubbles on the surface of the oil and air bubbles that cannot be released from within the fluid, can negatively impact lubrication. In general, the lubricant will slowly oxidize (contact with oxygen) after contact with air, but this process is slow and inevitable, normal, but if the air enters into the lubricant, the problem can be big.
Lubricating oil mixed in the air are mainly three kinds: dissolved in the oil air (invisible to the naked eye), suspended, trapped inside the oil can not be released bubbles, foam on the oil surface. Among them, the most harmful to the machine and lubricating oil is suspended, trapped in the oil inside the bubble.
Foam will gather, floating in the oil surface, the volume is relatively large, if there is foam, generally beware of the oil has often been formed inside the bubble. Bubbles suspended, stagnant in the oil inside, the volume is small, but the harm is great. Bubbles will cause turbidity of the oil, if the oil is turbid, you can take some oil samples, if there is a delamination, then the turbidity of the lubricant is caused by water or other liquid pollution. If it is left for a period of time, the oil sample returns to clear, then the oil is mixed with air bubbles.
Causes of air bubbles in lubricating oil:
1. Many reasons can cause bubbles and foam to increase in the lubricant, the most common of which is water in the lubricant. When the oil is mixed with water, the surface tension of the oil will be reduced, can not form large bubbles floating to the surface of the liquid, but broken into small bubbles suspended in the oil.
2. The lubricant is contaminated: the oil is mixed with other liquids, detergents, solvents and other substances.
Lubricant oxidation: oil oxidation caused by the reduction of anti-foaming liquid, some oil in the use of long time after the foam will increase the situation, the common reason is because of oil oxidation.
3. Additive depletion: anti-foam agent depletion will also cause an increase in bubbles, should pay attention to one point: anti-foam agent added more will also appear bubble problem. Some users see an increase in bubbles or anti-foam agent is consumed, will add anti-foam agent, anti-foam agent added more will also cause bubble problems.
4. Leakage: oil pipes, seals and other parts of the leakage.
5. Poor tank design: the tank is too small, no filtering bubbles filter, baffle, return pipe and suction pipe distance is too close, the oil flow rate is too fast to release bubbles.
6. The viscosity of the lubricant is not selected properly.
7. The danger of air bubbles and foam in the lubricating oil:
2. The lubricant is contaminated: the oil is mixed with other liquids, detergents, solvents and other substances.
Lubricant oxidation: oil oxidation caused by the reduction of anti-foaming liquid, some oil in the use of long time after the foam will increase the situation, the common reason is because of oil oxidation.
3. Additive depletion: anti-foam agent depletion will also cause an increase in bubbles, should pay attention to one point: anti-foam agent added more will also appear bubble problem. Some users see an increase in bubbles or anti-foam agent is consumed, will add anti-foam agent, anti-foam agent added more will also cause bubble problems.
4. Leakage: oil pipes, seals and other parts of the leakage.
5. Poor tank design: the tank is too small, no filtering bubbles filter, baffle, return pipe and suction pipe distance is too close, the oil flow rate is too fast to release bubbles.
6. The viscosity of the lubricant is not selected properly.
7. The danger of air bubbles and foam in the lubricating oil:
Air bubbles and foam are harmful to the lubricant and the machine. Air bubbles will accelerate the oxidative deterioration rate of the lubricant, accelerate the consumption of additives, affect heat dissipation, fail to form a complete lubricant film, and cause wear and tear on the equipment. Air bubbles in high-pressure systems can also cause localized high temperatures, causing rapid deterioration of the oil.
Hazards to equipment:
Air is easy to compress, there is gas in the lubricating oil, the thickness of the oil film will become thin or even rupture of the oil film, direct friction between the mechanical parts, resulting in wear.
Causes cavitation: air bubbles rupture under pressure, forming cavitation damage to metal surfaces.
Impact on mechanical operation: air bubbles will affect the stable operation of mechanical systems, such as hydraulic systems will appear unstable operation, uncontrolled action, the formation of varnish on the spool jamming, corrosion and other problems.
How to prevent air bubbles in lubricating oil?
What should be done when bubbles increase in the oil tank?
Use a clean, dry sampling bottle to take some oil samples from the drain and observe whether there is water in the oil flowing out - free water or cloudy, stratified, emulsified and whitish oil. If there is water, the foam is probably caused by water in the lubricant.
If it is not caused by water, check the leaks and oil level, if everything is normal, the oil should be sampled for oil testing, to detect whether it is contaminated by other chemicals or oil, or additives are depleted, oil deterioration.
If the oil tank is poorly designed, you can consider increasing the volume of the oil tank, the oil return area and the oil absorption area with baffles and filters.
If it is not caused by water, check the leaks and oil level, if everything is normal, the oil should be sampled for oil testing, to detect whether it is contaminated by other chemicals or oil, or additives are depleted, oil deterioration.
If the oil tank is poorly designed, you can consider increasing the volume of the oil tank, the oil return area and the oil absorption area with baffles and filters.
Conclusion: To ensure excellent mechanical lubrication, we must avoid any other substances and oil in the lubricant, the oil should be clean, dry, and not be contaminated by any other substances.
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