The stand or fall of a hydraulic system depends not only on the performance of the rationality of the system design and system component, also pollution prevention and treatment in the system. The system of pollution directly affects the service life of the working reliability of the hydraulic system and components. According to statistics, about 70% of the hydraulic system failure at home and abroad is caused by pollution.

The oil pollution. The hazards of oil pollution to the system are as follows.

1) Component contamination wear. Various contaminants in the oil cause various forms of wear on the components, and solid particles enter into the motion clearance, resulting in cutting wear or fatigue wear on the parts surface. Erosion wear is caused by the impact of solid particles on the surface of the element in a high-speed fluid flow. The water in the oil and the products of oil oxidation and deterioration corrode the components. In addition, air in the oil of the system causes cavitation, which results in erosion and damage to the surface of the element.

2) Fault of component blocking and clamping. Solid particles block the gap and orifice of the hydraulic valve, causing blockage and clamping of the spool, affecting the performance of work, even leading to serious accidents.

3) Accelerate deterioration of oil performance. Water and air in oil are the main conditions for oil oxidation, and metal particles in oil play an important catalytic role in oil oxidation. In addition, water and suspended air bubbles in oil significantly reduce the strength of the intermoving oil film, reducing the lubrication performance.