Reasonable Use of Hydraulic Oil

1. Factors influencing the quality of hydraulic oil

(1) Water. The moisture content of oil in water is in accordance with the technical standard of national standard GB/T1118.1-94. After testing, its quality index should not be greater than the trace. If the moisture in the oil exceeds the standard, it must be replaced; otherwise, it will not only damage the bearing, but also make The surface of the steel rusts, emulsifies, degenerates, and precipitates the hydraulic oil, hinders the heat transfer of the cooler, affects the valve work, reduces the effective working area of ​​the oil filter, and increases the abrasive effect of the oil.

(2) Oxidation. The working temperature of general mechanical hydraulic oil is 30-80°C. The life of hydraulic oil is closely related to its working temperature. Experience tells us that when the operating oil temperature exceeds 60°C, the service life of oil will be halved for every 8°C increase. That is, the oil life at 90°C is about 10% of the oil at 60°C because the oil is oxidized. Oxygen reacts with the hydrocarbons in the oil to slowly oxidize the oil, darken the color, increase the viscosity, and finally it may be so severe that the oxides cannot dissolve in the oil, and the brown mucus layer is deposited somewhere in the system and can easily clog up. The control of the oil passages in the components makes the wear of the ball bearings, spools, and pistons of the hydraulic pump intensify, and affects the normal operation of the system. Oxidation also produces corrosive acid. The oxidation process begins slowly. When it reaches a certain stage, the oxidation rate will suddenly increase, and the viscosity will suddenly increase. As a result, the working oil temperature will increase, the oxidation process will be faster, and the accumulated precipitates and acid will be more. Finally, the oil can no longer be used.

(3) Impurities. Impurities can not only wear the moving parts, but once they are stuck in the spool or other moving parts, it will affect the normal operation of the entire system and cause the machine to malfunction.

(4) Air. If the hydraulic oil circuit contains gas, when the air bubbles overflow, there will be an impact on the pipe wall and components to form cavitation, so that the system can not work properly, and a longer time will also lead to component damage.

(5) Physical and chemical reactions. The clean paint inside the tank will cause changes in the chemical properties of the oil.

2. Oil inspection and maintenance

Moisture content: Release 2-3cm of oil into a test tube, let it stand for a few minutes to make the air bubbles disappear, then heat the oil, (such as with a lighter), and at the same time, listen at the top of the mouth of the test tube to see if there is a slight "click" sound of water vapor. If yes, it means that the oil contains water.

Generally, there is no condition to check the water content of the system oil. The simplest method for checking is to wait for the whole machine to stand overnight. Open the oil drain plug at the bottom of the fuel tank and release a little oil to a container. Observe whether the oil is in the field. Contains moisture.

Odor and appearance: Compare unused oil and used oil samples, and compare them at the same temperature and in a glass dish. If the oil color is very different or there is a special odor, it indicates that The oil has deteriorated and needs to be replaced. If there is no significant difference in the color and odor of the two oil samples, the two oil samples can be placed at the same time for one night. If precipitation occurs at the bottom of the container with oil, the oil in the system must be finely filtered. Oil filter, and clean the tank.

In addition, the following oil matters should also be noted:

(1) Check the oil level before turning on the machine and check if the opening of each oil circuit is in the correct standby state.

(2) The machine runs at idle speed for about 5 minutes. Check whether there is air bubble in the level gauge oil. If it is a new car or a newly changed hydraulic oil, bubbles appear in the oil standard at idle. The air bubbles are allowed to disappear before the machine is allowed to work.

(3) Pay close attention to the temperature of the oil. When the machine is working for a period of time, if the oil temperature is too high, it can be stopped and rested. After the oil temperature is normal, it will work again to extend the service life of the system and the oil.

(4) It should pay attention to whether the various parameters of the hydraulic system are normal or not, and it is necessary to pay attention to the external characteristics of the system - sound. If the system has air intake, water, or oil, it will give an abnormal sound. At the same time, the reading of the instrument's reading fluctuations is not normal. In this case, it should be stopped and checked in time.

(5) Filter the hydraulic oil regularly. To control the impurity particles in the oil within the specified range.

(6) Change the hydraulic oil regularly. According to the requirements of the machine manual, oil changes regularly, and the oil filter is replaced at the same time. If there is a conditional test, whether to change the oil should be judged according to the result; the oil change period can also be established according to the requirements of the machinery use site and system, and the oil change interval Include equipment technology files.

Pay attention when changing the oil: The new oil and the old oil should be of the same specification and the same grade. Before changing the oil, all the old oil should be drained and rinsed completely, and the place where the valve body, hydraulic cylinder, etc. can't be placed and can not be flushed, The oil return pipeline can be disassembled and put into a temporary oil drum. After adding new oil, the new oil can be used to replace the old oil by inching the engine. The principle is that the injection of new oil is not less than the system filtration accuracy. The oil filter is filtered, if the site is indeed unconditional, the oil filter in the system should be replaced after adding the new oil for about 1 hour. After the new oil is idling, the oil level should be checked again, and new oil should be added as necessary.

(7) When the car wash or the machine is not in use, cover the oil tank to prevent moisture in the air from entering.