The correct and reasonable selection of hydraulic oil is of great importance to improve the reliability and economic efficiency of hydraulic equipment, prolonging the useful life of the system and the components, guaranteeing the safe operation of equipment and preventing accidents.
How to judge?
1. Simple judgment of moisture content in oil
(1)burst test: The thin metal sheet is heated to 110°C or more and a drop of hydraulic oil is added. If the oil burst proves that the hydraulic oil contains moisture, this method can test the water content of 0.2% or more of the oil.
(2) test tube sound test: release 2 to 3 ml of hydraulic oil to a dry test tube, and put a few minutes so that the oil bubbles disappear. The oil is then heated (eg with a lighter) while listening to the small "Pumba" sound of oil (located at the top of the tube mouth). The sound is caused by the water vapor generated when the water particles in the oil collide with boiling.
(3)the cotton ball test: Take a clean cotton ball or tissue paper, lick a little measured hydraulic oil, and then ignite, if you hear a "burst" burst sound and flash phenomenon, prove that the oil contains water.
2. the appearance of color judgment
(1) The hydraulic oil is opaque and opaque, indicating that the hydraulic oil has entered the water;
(2) The hydraulic oil is dark brown, indicating high temperature oxidation of hydraulic oil.
3. the smell of judgment
A pungent odor appears, indicating that the hydraulic oil has been oxidized and deteriorated by high temperatures. If there is diesel or gasoline smell, it may be mistakenly added to the fuel.
4. simple judgment of viscosity
(1) "handcuffs" method
The size of the viscosity is judged by hand. Due to changes in viscosity with temperature and personal feelings, there is often a large amount of human error. However, it is feasible to compare the viscosity changes before and after use of the same oil in this way.
(2) glass tilt observation method
Each of the two different hydraulic oils is dribbled on a sloping clean glass to see which flow is faster and its viscosity is lower.
5.oil contamination of the oil droplet spot test:
Take a drop of the measured hydraulic oil on the filter paper to observe the change of the spot, the hydraulic oil quickly spreads, and there is no sediment in the middle, indicating that the oil is normal; the hydraulic oil spreads slowly to deposits, indicating that the oil has deteriorated. There are many methods to determine the hydraulic oil quality, such as chemically determining whether the oil has entered water. The above are just a few simple methods considered from the field of engineering machinery field work and poor conditions.
