How to Identify the Quality of Hydraulic Oil?
The quality of hydraulic oil can be identified from the antioxidation, the anti-foaming characteristic, the abrasion resistance, the smell and color. And the good hydraulic oil can 
prolong the life of gantry crane.
1. Antioxidation. If you have enough time, you can put some sample into a transparent bottle, screwing the bottleneck closely. And then put it in the sun to insolate for some time. If the color becomes very severe, it indicates that the oil’s function is not good and the life is very short. You also can heat two different samples to 150℃ and keep two hours. If the aberration becomes very bigger that indicates its quality is bad.
2. Anti-foaming characteristic. You can take the same capacity from two different oils to put into two sample bottles and then sealed closely. Then shocking severely for a long time, and observing the speed of foam disappear after they rest. The speed of disappearance is quicker and the quality of oil is better.
3. Abrasion resistance. You can us the friction tester. If the sample can burden more weights, the abrasion resistance is better.
4. Smell and color. As usual, the good oil has very high refining base oil, light color and weak smell, the additive is added and the color is also light.
