Selection of hydraulic oil for the hottest Truck C

Selection of hydraulic oil for truck crane (2)

2. Simple judgment on the quality of hydraulic oil on site:

(1) simple judgment of water content in oil

a before starting the experimental machine, burst test: heat the thin metal sheet to above 110 ℃, drop a drop of hydraulic oil. If the same sample is subjected to impact test at high to low temperature, the oil burst proves that the hydraulic oil contains water, This method can detect the water content of more than 0.2% in the oil

b test tube sound test: Release 2 ~ 3 ml of hydraulic oil into a dry test tube and place it for a few minutes to make the oil bubbles disappear. Then heat the oil (e.g. with a lighter) and listen to the small "Peng Peng" sound of the oil (at the top of the test tube mouth). The sound is caused by water vapor produced when water particles in oil collide and boil

c. Cotton ball test: take a clean cotton ball or paper, dip it in a little of the measured hydraulic oil, and then ignite it. If you hear "crackling" cracking sound and flashing phenomenon, it is proved that the oil contains water

(2) at present, the method of determining the shrinkage rate of various plastics (forming shrinkage + Post shrinkage) color judgment

a, the hydraulic oil is milky white and turbid, indicating that the hydraulic oil has entered water

b, the hydraulic oil is dark brown, indicating that the hydraulic oil is oxidized at high temperature

(3) odor judgment

there is an irritating odor. At the same time, it indicates that the hydraulic oil is oxidized and deteriorated at high temperature. If there is a smell of diesel or gasoline, fuel may be added by mistake

(4) simple judgment of viscosity

a, "hand twisting" method: judge the viscosity by hand. Because the viscosity changes with temperature and personal feeling, there are often large human errors. However, it is feasible to use this method to compare the viscosity changes of the same oil before and after use

b, glass tilt observation method: take a drop of two different hydraulic oils and drop them on an inclined clean glass to see which one flows faster, then its viscosity is low

(5) oil droplet spot test of oil pollution:

take a drop of the measured hydraulic oil on the filter paper and observe the change of the spot. The hydraulic oil diffuses rapidly and there is no sediment in the middle, indicating that the oil product is normal; The hydraulic oil diffuses slowly and deposits appear in the middle, indicating that the oil has deteriorated