How to handle the black and turbid hydraulic oil of excavator?
September 04, 2023
Hydraulic oil plays a role in lubricating various components in the hydraulic system. 90% of faults in the excavator hydraulic system are caused by hydraulic oil problems. If 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 abnormal wear of various hydraulic system components such as injection, valves, multi way directional valves, oil seals, etc. in the excavator main pump, Over time, excessive gaps between various components have resulted in internal leakage, which seriously affects the continuity and weakness of excavator actions. 1. Hydraulic oil action Hydraulic oil mainly plays a role in energy transmission, wear resistance, system lubrication, corrosion prevention, rust prevention, cooling, and other functions in hydraulic systems. 2. Precautions for selecting hydraulic oil 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. System working conditions: The higher the requirements for actuator speed, system pressure, and mechanism action accuracy, the higher the requirements for wear resistance and load-bearing capacity of the hydraulic oil used. Tank size: The smaller the tank, the higher the requirements for oil oxidation stability, extreme pressure wear resistance, air release, and filtration. Environmental temperature: Reasonable selection of hydraulic oil. If there is no open flame nearby, the working temperature is below 60 ℃, and the load is relatively light, ordinary hydraulic oil can be used; If the equipment needs to be started at very low temperatures, low-temperature hydraulic oil must be selected.
3. Deterioration of hydraulic oil and its causes 1) Hydraulic oil is too dirty and turns black Long working hours, aging and deterioration of oil seals. Metal impurities such as iron filings are the main factor affecting the blackening of excavator hydraulic oil. Due to high-speed rotation with the pump, repeated operation of the hydraulic valve core, and repeated operation of the oil cylinder, debris can be generated, which can affect the quality of the hydraulic oil if 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, the hydraulic oil in the oil tank should be completely emptied, and the oil tank should be wiped clean with a cotton cloth before adding new oil. If not emptied, there may be a large amount of iron filings remaining in the fuel tank, which can also cause the new oil to be contaminated and turn black. External reason: The working environment of the equipment is relatively poor, and external pollutants enter the hydraulic oil. The working environment of the excavator is too poor, causing clogging of the filter element; Inadequate dust prevention measures during cleaning, oil change, and maintenance resulted in impurities being brought into the hydraulic system during operation. Therefore, it is necessary to regularly check whether the hydraulic system of the excavator is closed and whether the breathing hole is intact; Check if the sealing of the exposed components of the hydraulic part of the equipment is intact, such as the dust ring of the oil cylinder. 2) Hydraulic oil appears white and turbid
If the hydraulic oil exhibits white turbidity, the possibility of solid or liquid viscous impurities can be ruled out, and it can only be caused by water or air. The most reliable way is to sample hydraulic oil and send it to a testing agency for testing. You can also drop the oil sample onto a hot iron plate. If bubbles appear (water turns into steam at high temperatures to form bubbles), it can be determined that there is water in the hydraulic oil. If there is water mixed in the hydraulic oil causing 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 high moisture content causes hydraulic oil emulsification, a new hydraulic oil needs to be replaced. If it is determined that there is air mixed in the hydraulic oil causing turbidity, the hydraulic system pipeline should be checked for air leakage and the source of air mixing should be cut off.
4. Preventive measures
1) Choose the appropriate hydraulic oil
The equipment manual specifies the standards for selecting hydraulic oil based on variety, grade, and viscosity. When purchasing hydraulic oil, it is important to go to a reputable brand store to avoid buying counterfeit and inferior products.
2) Hydraulic oil high temperature
During the use of the equipment, controlling the working temperature of the hydraulic oil is generally considered normal at around 50-80 degrees Celsius. If it exceeds 90 degrees Celsius, there may be problems, and the hydraulic oil will accelerate deterioration.
3) Hydraulic oil tank seal
The hydraulic oil tank must be properly sealed to prevent pollutants from entering the hydraulic system.
4) Regular inspection
Regularly check the condition of hydraulic oil, clean the filter element and oil tank, and replace contaminated hydraulic oil in a timely manner.
5) Pipeline interface sealing
Pay more attention to checking the sealing of pipeline interfaces, checking the joints and sealing devices between hydraulic system pipelines and components. If damage is found, replace them in a timely manner, and tighten the joints of each pipeline.
