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Technical Article

Hydraulic Press

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Key points of reasonable use of hydraulic oil

After the working medium is selected, if it is used improperly, the hydraulic system will malfunction due to changes of the liquid.

① It is necessary to verify the type and brand of the oil (the factory inspection form should be consistent with the provisions of the technical documents).

②It must be filtered before use.

③The hydraulic system should be thoroughly cleaned before filling.

④The oil must generally be used alone and cannot be mixed at will.

⑤ Strictly carry out pollution control.

⑥In the process of storage, transportation and filling of working fluid, as well as the design and manufacture of hydraulic system, certain protective and filtering measures should be taken to prevent the oil from being contaminated, so that the cleanliness of the medium meets the relevant regulations.

⑦ Pay attention to safety, pay attention to fire prevention of oil; do not touch human skin with phosphate ester liquid.

⑧ Pay attention to the impact of changes in working conditions on its performance. Some main performance parameters of the media should be tested regularly and frequently with reference to relevant standards.

⑨The amount of oil added to the system should reach the highest mark line position of the oil tank.

⑩Pay attention to the influence of high and low temperature environment on the performance of hydraulic oil.

High temperature environment

Low temperature environment

High temperature makes the viscosity of the oil become smaller, the viscosity is too low, the leakage of the hydraulic system increases, the efficiency decreases, and the hydraulic system even fails to work normally

Low temperature increases the viscosity of oil. If the viscosity is too high, the self-priming ability of the hydraulic pump will decrease, and the system pressure loss and power loss will increase. It is generally believed that when the viscosity is greater than or equal to 1000mm2/s, the hydraulic system cannot work normally, and when the viscosity is greater than or equal to 2000mm2/s, the hydraulic system cannot start normally.

High temperature intensifies the oxidation of oil products. Some ketones, acids, gums, asphaltenes and other substances are gradually formed in the oil products, which pollute the oil products and shorten the service life of the oil products. When the oil is oxidized to a certain degree, the oil is invalid and cannot be used

The low temperature causes the water in the oil to solidify, and the solidified water adheres to the surface of the hydraulic components, which may cause the hydraulic valve to block, the filter to block, and the hydraulic system can not work normally

The high temperature causes the chemical decomposition of the lubricating film formed on the metal surface of the friction part. The lubricating film is destroyed

The low temperature causes the rubber sealing material in the hydraulic system to shrink, harden, etc., reduce the sealing performance and even cause the seal to fail

High temperatures often cause increased corrosion of steel and other non-ferrous metals in oil, resulting in damage to the surface of parts, and corrosion products

Low temperature will cause the oil to shrink, especially the hydraulic oil in the closed cavity, which will cause the pressure to drop or even produce negative pressure

High temperature is more likely to produce bubbles. The water in the oil vaporizes at high temperature and turns into water vapor. The gas (mainly air) dissolved in the oil produces bubbles due to the high temperature volatilization. Air bubbles destroy the lubricating oil film, cause sintering of the friction surface or increase wear, and accelerate the oxidation and deterioration of the oil, which affects the accuracy and sensitivity of hydraulic components, and cannot meet the requirements of the hydraulic system in severe cases.


High temperature deteriorates the performance of rubber seals in hydraulic systems, which can swell and soften rubber, accelerate rubber aging, and even seal failure


The high temperature expands the volume of the hydraulic oil and increases the pressure of the hydraulic oil enclosed in the cavity, causing danger



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| TIME: 2021.08.31    VIEW: