The working environment of hydraulic excavators is dusty and seriously polluted. About 70% of the system failures are caused by pollution. During oil level inspection, oil filling and maintenance, impurities enter the system through damaged oil seals or sealing rings. Common pollutants include dust, sand, chips, welding slag, metal embroidery pieces, and wear particles of sealing materials, The anti-corrosion coating on the inner surface of oil tank and oil filter is peeled off, and particles such as slag are broken. Pollutants are easy to block the hydraulic components, make their action failure or failure, and affect their working performance. When the filter screen is seriously blocked, it will completely lose its filtering effect, leading to a vicious circle in the hydraulic system. Pollutants into the hydraulic cylinder, easy to scratch the inner surface of the cylinder, the seal damage intensified, leakage increased, leading to instability, crawling, deceleration, abnormal noise or insufficient thrust and other failures, unable to meet the stability and reliability requirements of the system. Pollutants mixed in the oil for a long time will react with the oil, and the products will corrode the components. It is better to filter the oil once every two months, and the oil filter should be replaced half a year.
