Three abnormal conditions of hydraulic oil

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Hydraulic oil can be regarded as the “blood” of hydraulic machinery. Most faults in hydraulic systems can have their causes identified by checking the condition of the hydraulic oil, thereby allowing those faults to be resolved. 1. The hydraulic oil is turbid due to impurities. There are mainly three types of impurities in hydraulic oil: solid impurities (shards, solid particles, solid impurities formed as a result of the degradation of the hydraulic oil, etc.), liquid impurities (primarily water, followed by viscous impurities resulting from the degradation of the hydraulic oil), and gaseous impurities (mainly air). If the hydraulic oil becomes white and cloudy, solid impurities or viscous liquid impurities can be ruled out; it must be caused by water or air. Hydraulic oil can be sampled for testing. Drop a sample of oil onto a hot iron plate; if bubbles appear (water turns into steam at high temperatures, forming bubbles), it can be determined that there is water in the hydraulic oil; otherwise, air is present in the hydraulic oil. If turbidity occurs due to water mixed in the hydraulic oil, let the hydraulic oil stand for some time to allow the water to settle at the bottom of the tank, and then remove the water. However, if the high moisture content causes the hydraulic oil to emulsify, it is necessary to replace it with new hydraulic oil. If it is determined that the turbidity is caused by air mixed in the hydraulic oil, check whether there are leaks in the hydraulic system’s pipelines and eliminate the source of air intrusion. 2. Abnormally high temperature of hydraulic oil. The main reasons for abnormally high temperatures of hydraulic oil are as follows: First, the pressure setting of the safety valve is too low, causing most of the hydraulic oil to flow back to the tank through the safety valve, which results in a low efficiency of work performance by the hydraulic system; when the load is high, most of the energy is converted into heat in the hydraulic oil, leading to very high temperatures. Second, the cooling effect of the cooling system is poor, which also causes the hydraulic oil temperature to rise excessively ； Third, the hydraulic oil circulates too frequently in the oil circuit (often due to insufficient oil volume), which makes heat dissipation difficult and causes the temperature to rise. Fault diagnosis should proceed from the easiest to the more difficult tasks; first, check the level of oil in the hydraulic tank. If the oil level is low, it should be topped up to the standard level promptly. When refilling, care should be taken to use hydraulic oil of the same grade, and it should also be filtered before use. If the oil level is appropriate, it is necessary to check whether there are any blockages in the oil cooling system. If it is found that the oil cooling system is obstructing air flow, it should be cleaned promptly to ensure proper air circulation and facilitate heat dissipation. Sometimes, if the fan belt is too loose or slips, it can also lead to reduced fan efficiency and poor cooling performance; it should be checked and adjusted promptly, and a new belt should be replaced if necessary. If there are no issues with the oil level, the oil cooling system, or the fan belt, it can be concluded that the set pressure of the main safety valve is below the standard value. The pressure setting of the main safety valve should be adjusted back to the standard value. 3. Dirty hydraulic oil – The hydraulic oil being turbid and dirty may be due to chemical changes that have occurred in the oil as a result of long-term use ； It could also be that physical changes occurred due to too many impurities. As long as the causes of these two changes are identified, corresponding measures can be taken. In the absence of the necessary testing equipment and instruments, a simple and practical method for determining whether hydraulic oil has undergone chemical or physical changes is to use filter paper for testing. Take a sample of the hydraulic oil, drop it on filter paper, and observe the oil spot that forms. If layering or ring-like patterns are evident in this spot (with the center being dirtier and becoming clearer toward the edges), it indicates that the hydraulic oil has deteriorated and must be replaced with fresh oil ； If the oil stain spreads evenly, it indicates that the hydraulic oil contains too many impurities; it is necessary to check the filter promptly, replace the filter element, and replace the hydraulic oil if needed. For more information on lubricants, please visit the website of Jieyouwang filter machines. You can find it by searching for “Jieyouwang” on Baidu. The site contains a lot of information on the use, maintenance, and regeneration of hydraulic oil. In general, this approach allows hydraulic oil to be used for over five years, keeping it in a condition similar to that of new oil. There are also videos on hydraulic oil filtration on the site; such tools are very useful for maintaining hydraulic equipment and represent the best way to extend the lifespan of hydraulic oil. Please use this information as a reference!