1. A simple way to judge the oil contains water
A. Explosion testing: a thin sheet of metal was heated to above 110 ℃ and put a drop of hydraulic oil on it, if the oil blowout, it proofs that the oil contains water. This method can check out the water content in oil for more than 0.2%.
B. Test the sound of tube: release 2 ~ 3 ml of hydraulic oil into a dry test tube and place it for a few minutes to make the gas bubble disappear. Then heat the oil (for example, with a lighter) and listen to the banging noise at the top of the tube. The sound is caused by water vapor when the water in the oil boils and collides.
C. Test with cotton ball: take clean cotton ball or cotton paper, dip it in a small amount of hydraulic oil, and then ignite, if you hear crackle and see flash, it proves that the oil contains water.
2. Judge from the color of appearance
A. If the hydraulic oil is milky white, it indicates that the hydraulic oil contains water;
B. If the hydraulic oil is dark brown, it indicates that the hydraulic oil is oxidized by high temperature
3. Judge from the smell
The presence of a pungent odor indicates that the hydraulic oil is oxidized by high temperature, and if accidentally added fuel into it, there will be a smell of diesel or gasoline.
4. Simple judgment of viscosity
A. "Hand twist" method: use the hand to judge the size of the viscosity. Because the viscosity changes with the temperature and the individual's feeling, there is often a large human error. However, it is feasible to compare the changes of viscosity before and after using of the same hydraulic oil in this method.
B. Glass tilt observation method: place two drop of two different hydraulic oil in a slanted clean glass to see which one flows faster and the viscosity indeed is lower.
5. Oil droplet test for oil pollution:
Put a drop of hydraulic oil on the filter paper to observe the change of the spot. If the hydraulic oil quickly diffused and there was no sediment in the middle, it indicates that the oil was normal. If the hydraulic oil spreads slowly and the intermediate has deposit sediment, it indicates that the oil has gone bad.