The hydraulic oil of the excavator turns black and cloudy, but the oil is ok, what is the reason?
May 10, 2022
Basically, 90% of the failures of the hydraulic system of the excavator are caused by the problem of the hydraulic oil. If it is not replaced for a long time, the hydraulic oil will turn black and the viscosity of the hydraulic oil will decrease, which will directly lead to the injection, valve, and multi-way reversing in the main pump of the excavator. The abnormal wear and tear of various hydraulic system components such as valves and oil seals will cause excessive clearance between the components and internal leakage, which will seriously affect the continuity and weakness of the excavator. Hydraulic oil function: Hydraulic oil mainly plays the role of energy transmission, anti-wear, system lubrication, anti-corrosion, rust prevention and cooling in the hydraulic system.
Points to note when choosing hydraulic oil (1) The hydraulic pump is one of the most sensitive components to the viscosity and viscosity-temperature performance of hydraulic oil. Therefore, the requirements of the pump for hydraulic oil in the system are often used as an important basis for selecting hydraulic oil. (2) System working conditions: If the requirements for the actuator speed, system pressure and mechanism action accuracy are higher, the requirements for the wear resistance and bearing capacity of the hydraulic oil used are also higher. (3) Fuel tank size: The smaller the fuel tank, the higher the requirements for the oil's anti-oxidative stability, extreme pressure and wear resistance, air release and filterability. (4) Ambient temperature: hydraulic oil should be selected reasonably. If there is no open fire nearby, the working temperature is below 60℃, and when the load is light, ordinary hydraulic oil can be selected; if the equipment must be started at a very low temperature, low-temperature hydraulic oil must be selected. Oil.
Hydraulic oil deterioration phenomenon and reasons 1. The hydraulic oil is too dirty and turns black Internal reasons: mainly due to the aging and deterioration of the oil seal after a long working time. Metal impurities such as iron filings are the main factors affecting the blackening of excavator hydraulic oil. Due to the high-speed rotation of the pump, the repeated operation of the hydraulic valve spool and the repeated operation of the oil cylinder, wear debris will be generated, which will affect the quality of the hydraulic oil if it is not cleaned for a long time. In addition, if it is a newly purchased excavator, a large amount of metal impurities will be generated during the running-in period. When changing the oil, all the hydraulic oil in the oil tank should be emptied, and the oil tank should be wiped with a cotton cloth before adding new oil. If it is not emptied, there may be a lot of iron filings remaining in the fuel tank, which will also cause the new oil to be contaminated and blackened. External reasons: The main reason is that the working environment of the equipment is relatively poor, and external pollutants enter the hydraulic oil. The poor working environment of the excavator causes the filter element to be blocked; the dustproof measures are not in place during the cleaning, oil change and maintenance process, and impurities are brought into the hydraulic system during operation. Therefore, digging buddies need to frequently check whether the hydraulic system of the excavator is closed and whether the breathing hole is in good condition; check whether the seal of the exposed parts of the hydraulic part of the equipment is in good condition, such as the dust ring of the oil cylinder. 2. The hydraulic oil is white and turbid If the hydraulic oil appears white turbid, the possibility of solid impurities or liquid viscous impurities can be excluded, which can only be caused by water or air. The most reliable way is to sample the hydraulic oil and send it to the testing agency for testing. The oil sample can also be dropped on the hot iron plate. If bubbles appear (water turns into water vapor to form bubbles at high temperature), it can be determined that there is water in the hydraulic oil. If the hydraulic oil is mixed with water to cause turbidity, let the hydraulic oil stand for a period of time, let the water sink to the bottom of the hydraulic oil tank, and then remove the water. However, if the moisture content is too high and the hydraulic oil is emulsified, it needs to be replaced with a new hydraulic oil. If it is determined that air is mixed with the hydraulic oil to cause turbidity, check the hydraulic system pipeline for air leakage and cut off the source of air mixing. Precaution 1. Select the appropriate hydraulic oil. The standard for the selection of hydraulic oil is specified in the general equipment manual, which is determined according to the variety, brand and viscosity. When buying hydraulic oil, be sure to buy it in a regular brand store to avoid buying fake and shoddy products. 2. Control the working temperature of the hydraulic oil during the use of the equipment. Generally, it is normal at around 50-80 degrees. If it exceeds 90 degrees, there will be problems, and the hydraulic oil will deteriorate rapidly. 3. The hydraulic oil tank must be properly sealed to prevent contaminants from mixing into the hydraulic system 4. Regularly check the hydraulic oil condition, clean the filter element and the oil tank, and replace the contaminated hydraulic oil in time 5. Usually, pay more attention to check the sealing of the pipeline interface, check the joints and sealing devices between the pipelines and components of the hydraulic system, and replace them in time if they are damaged, and tighten the joints of each pipeline. The importance of hydraulic oil to excavators is self-evident. A warm reminder: on the issue of hydraulic oil, oil sellers should tell customers that they must raise their awareness and achieve early prevention and early detection. If the hydraulic oil deteriorates, it must be replaced as soon as possible.
