How to choose hydraulic oil correctly
Hydraulic oil is an indispensable transmission medium for hydraulic transmission. It is used as the transmission medium of hydraulic system. With the development of hydraulic technology, the quality requirements of hydraulic oil for construction machinery and equipment are higher and higher. Therefore, the selection of hydraulic oil should also have certain standards. What are the standards for selecting hydraulic oil?
Selection standard of hydraulic oil
Proper viscosity: too high viscosity will result in slow reaction and excessive sludge, and too low viscosity will cause the phenomenon that the pressure can not reach. Appropriate viscosity index: select the oil with the corresponding viscosity index according to the application environment. In case of flow operation or large temperature difference between day and night, oil with high viscosity index must be used. For example, in Guangdong, due to the small temperature difference, this is not a special requirement. But if the use of the environment is high temperature, must use a high viscosity index of hydraulic oil. Because the characteristics of hydraulic oil thinning at high temperature and thickening at low temperature have an impact on the pressure generated by the hydraulic system.
Δ anti-wear characteristics: for heavy load or long-term use of machinery that does not change the oil, oil with excellent anti-wear performance should be used, otherwise the pressure will be lost under heavy load conditions, or the effect will not be achieved due to the failure of additives due to the failure of additives. For some precision vane pump, we must use the oil with excellent anti-wear, otherwise it will shorten the service life of the pump and aggravate the wear of the pump. Δ oxidation stability and oil sludge resistance: if the operating temperature is higher than 70 ℃, the aging and deterioration speed of oil will be doubled. In the case of high temperature, such as die casting, pottery making, steel making, etc., the high temperature resistance and oxidation resistance of oil products should be emphasized. If the oil is oxidized, sludge will be formed, causing mechanical failure. For machinery used in ordinary temperature environment, the oil with poor oxidation resistance can not be used for half a year, the medium wear resistance is about one year, and extreme pressure anti-wear is about two years. Δ anti foam characteristics: anti foam property is particularly important for large-scale hydraulic system, and foam will cause pressure instability. Special environmental requirements: in some high-temperature environments, oil products are required to be fireproof, such as die-casting and steel-making industries. It is better to use fire-resistant hydraulic oil. Although the unit price is expensive, the service life is several times longer, which is more cost-effective.
Specification for use of hydraulic oil
The hydraulic oil should be tracked and monitored regularly to avoid the oil working at high temperature. Otherwise, the oil will be oxidized and deteriorated, resulting in the formation of oil sludge and carbon deposition. The storage, transportation and filling of hydraulic oil should be clean to avoid oil pollution. Δ regularly sample and analyze the oil, detect the key physical and chemical indexes such as viscosity, acid value and water content of the oil, and establish relevant record accounts. The oil filter element shall be replaced regularly, and the solid particles such as iron chips and sealing rubber fragments generated by relative movement of components in the system shall be filtered to ensure the cleanliness of the oil. The system of replacing hydraulic oil regularly was established, and the hydraulic oil was changed regularly according to the visual inspection and physical and chemical analysis indexes. When changing oil, pay attention to the following points: 1. Oil products of different manufacturers and brands shall not be mixed. 2. When the hydraulic oil with equivalent viscosity is used instead, sampling should be conducted in advance for mixing test of the two oil products, otherwise it can not be replaced. 3. The oil change time should be arranged during the study period. 4. When replacing new oil, the original oil should be drained and the oil tank should be cleaned thoroughly.