A guide to avoiding pits in the detection of the three major pollutants of lubricating oil!

December 06, 2021

Contamination of lubricating oil is a complicated problem. Sometimes it can be found by daily inspection, but not in some cases, and some contamination cannot be observed by naked eyes. Moreover, for all the pollution, when it can be detected by the naked eye, it means that it is already serious. In short, the pollution of lubricating oil should be detected and treated early, especially for more sensitive and critical equipment. Oil detection can accurately analyze the contaminants in lubricating oil by detecting oil, just like finding abnormal conditions in the human body through blood testing.

Particulate matter pollution and its detection technology

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Particulate matter is the most harmful pollutant. They enter the lubrication system and cause abrasive wear, metal crushing and scratching, and metal fatigue. Particles generally have a certain degree of hardness. Many particles are very small in size and can pass through the gaps between parts and circulate inside the equipment, causing wear. Common particles include dust, grit, fine metal particles generated during equipment operation, rust slag, etc.

Particulate pollution not only harms the equipment itself, but also shortens the life of the lubricant. Abrasive wear will increase the metal powder content in the oil. These fine metal particles will not only further wear the equipment, but also accelerate the oxidation and deterioration of lubricating oil, because the metal powder will catalyze the oxidation rate of the oil. Given that the hazards of these particles are chained, it is important to monitor and deal with them early.

Oil detection can find fine particles in the oil, as well as early wear and tear of equipment. By detecting the particle count in the oil, we can understand the cleanliness of the oil and whether it has entered particulate contaminants. In addition, through metal analysis, we can find the early wear of the equipment. When the particles and the metal of the equipment are abrasively worn, the scraped metal can be monitored. Through the analysis of the composition of the metal, the wear source can also be found. For example, the material of the gear is mostly iron with a small amount of other alloy components (chromium, nickel, manganese, etc.).

If particulate matter is found to enter the lubricating oil, general remedial measures include: finding where the particulate matter entered, then blocking the source, filtering to remove the particulate matter-but this approach may not always be effective. Sometimes it is difficult to filter the oil to completely remove the particulate matter, and the oil has to be replaced. If the wear is obvious, it is recommended to perform a ferrography analysis, which can determine the degree of wear and guide equipment maintenance.

Moisture detection technology

Moisture is a common pollutant. Although the hazard is not as serious as particulate matter, moisture can destroy the lubrication effect, deteriorate the oil, and cause equipment wear. Moisture can also cause metal corrosion. There are three forms of water in lubricating oil: dissolved water, emulsified water, and free water. Among them, emulsified water is the most harmful.

Dissolved water is the water that has been dissolved in the lubricating oil. Lubricating oil is hygroscopic and will absorb moisture in the air, so it will contain a small amount of moisture. Generally speaking, a small amount of dissolved water will not cause any harm, unless certain circumstances require particularly strict requirements for the water content of the lubricating oil. The maximum allowable dissolved water content of lubricating oil is the water absorption saturation point. Before reaching the water absorption saturation point, although the lubricating oil contains water, it will not show signs of water, such as emulsification, turbidity, and reduced transparency.

After the lubricating oil enters the water, if it is not separated from the oil, the tiny water droplets are suspended in the oil and become a suspension, which becomes emulsified water. Emulsified water is the most harmful. When the lubricating oil is emulsified, the water content has exceeded the saturation point. When the oil contains emulsified water, the transparency of the lubricating oil will be reduced, turbid, and the color will become white or even milky white. Emulsified water is very harmful because it can flow freely and contaminate the oil in the entire lubrication system. In addition, water will destroy the lubricity of the oil. After the emulsified water reaches the pressure-bearing area where the equipment is running, these areas will be poorly lubricated, friction aggravated and wear.

When water and lubricating oil are completely separated, it becomes free water. Free water is relatively less harmful, but it can also cause problems. First, free water may also circulate with the lubricating oil, causing oil to emulsify. In addition, the water in the oil will weaken the demulsification of the lubricating oil, resulting in increased foam, consumption of additives in the lubricating oil, shortening the life of the lubricating oil, and easy to breed bacteria.

In addition to poor lubrication, the damage to equipment caused by moisture also includes hydrogen embrittlement and rust. Lubricating oil can prevent metal corrosion. If water enters the oil, it will easily cause metal corrosion.

When lubricating oil is found to have entered water, the correct way to deal with it is to first find the source of water, cut off the source, and then take measures to remove water. In severe cases, it is best to change the oil, which is best determined by oil testing.

Mix in other lubricating oil

When using lubricating oil, avoid contact with other oils. But some situations, such as leakage, using the wrong lubricating oil when refueling (the wrong lubricating oil viscosity or the wrong additive type), etc., will cause different lubricating oils to mix.

For example, mineral oil is not compatible with conventional PAG synthetic oil (non-oil-soluble PAG). If these two oils are mixed, the viscosity of the mixed oil will increase and sludge will be formed. Other phenomena include increased acid value and blockage of the filter element by the sludge. At the same time, due to poor lubrication due to mixing, equipment wear will also occur.

When the lubricating oil is mixed with other oils, the solution is to change the oil and flush the lubrication system, and it cannot be removed by filtering.

Using the wrong type of lubricant is also a common problem. It may be caused by accidentally adding the wrong oil when changing the oil, or simply selecting the wrong oil. For example, if the equipment requires extreme pressure lubricating oil (EP) or anti-wear lubricating oil (AW), and the user mistakenly adds general anti-oxidant and anti-rust oil, it will cause wear during the operation of the equipment.

If the equipment with higher requirements on the demulsibility of lubricating oil is mixed with oil with detergent and dispersant, the demulsibility/oil-water separability of the oil will be weakened. For example, mixing engine oil in steam turbine oil and mixing 1 liter of engine oil into 7000 liters of steam turbine oil can destroy the demulsibility of the steam turbine oil. Therefore, it is important to avoid mixing lubricating oils. In this case, you need to replace all the oil and flush the lubrication system.

Author:

Mr. James

E-mail:

sales@cn-lubricantadditive.com

Phone/WhatsApp:

+86 13783582233