The good or bad of a hydraulic system not only depends on the rationality of the system design and the performance of the system components, but also because of the pollution protection and treatment of the system. The pollution of the system directly affects the reliability of the hydraulic system and the life of the components. According to the statistics, about 70% of the domestic and foreign hydraulic pressure system faults are due to pollution. Cause.
1, the main harm of oil pollution to the system is as follows:
1) pollution and wear of components
All kinds of contaminants in the oil cause various forms of wear and tear, and solid particles enter into the clearance of the motion pair, and the surface of the parts can be worn or worn. The impact of solid particles on the surface of high-speed liquid flow causes erosion wear. The oxidation and deterioration of water and oil in oil will cause corrosion to the components. In addition, the air in the oil system causes cavitation, resulting in surface erosion and destruction of components.
2) component plugging and clamping failure
Solid particles block the gaps and orifices of hydraulic valves, resulting in blockage and clamping of the spool, affecting the performance and even causing serious accidents.
3) accelerating the deterioration of oil performance
The water and air in the oil are the main conditions for the oxidation of the oil, and the metal particles in the liquid play an important role in the oxidation of the oil. In addition, the water and suspended bubbles in the liquid can significantly reduce the strength of the oil film between the movement pairs and reduce the lubrication performance.
2, the species of pollutants
Pollutants are the substances which are harmful to the system in the fluid of the hydraulic system. It exists in different forms in the oil liquid, and can be divided into solid pollutants, liquid pollutants and gaseous pollutants according to their physical forms.
Solid pollutants can be divided into hard pollutants: diamond, cutting, silicon sand, dust, worn metal and metal oxide; soft pollutants include additives, condensate of water, decomposition and polymer of oil, cotton silk and fiber brought in during maintenance.
Liquid pollutants are usually the slotting oil, water, paint, chlorine and halides that do not meet the requirements of the system. Usually, we are difficult to remove, so we should choose hydraulic oil that conforms to the system standard when choosing hydraulic oil to avoid some unnecessary failures.
Gaseous pollutants are mainly mixed with air in the system.
These particles are often so small that they can not be precipitated and suspended in the oil, and finally squeezed into the gaps of various valves. For a reliable hydraulic system, these gaps are very important for the realization of limited control, importance and accuracy.
3. Sources of pollutants:
The sources of pollutants in the system are mainly in the following aspects:
1) external intrusive pollutants: the external intrusive pollutants are mainly sand or dust in the atmosphere, usually through the gas tank, the seal axis of the oil cylinder, the pump and the motor and other axes. The main effect is the use of the environment.
2) internal pollutants: components in the processing, assembly, commissioning, packaging, storage, transportation and installation of the residual pollutants, of course, these processes are unavoidable, but can be reduced to the lowest, some special components in the assembly and commissioning of the clean room or clean platform environment. 3) the pollutants produced by the hydraulic system: particles produced by the wear of components during the operation of the system, the sand falling off from the casting, the metal particles falling off on the pumps, valves, and joints, and the rust and spalling of the pipes and the particles produced by the oxidation and decomposition of its oil, and the more serious is the system tube. Tao has not been washed and has a lot of impurities before it is formally put into operation.