Hydraulic system is executive parts in Industrial machines. hydraulic oil is the energy transmission medium. Using low-grade hydraulic oil, ranging from hydraulic valve block, hydraulic motor damage, and at the damage caused by the replacement of the hydraulic system, serious damage up to several million.
Here is the source way of bad oil:
(1) with low-quality base oil or diesel dissolved rubber impersonate any hydraulic oil.
(2) posing with a general hydraulic oil to anti-wear hydraulic oil.
(3) recovery of oil by using a number of simple processing, posing a particular brand of oil.
Use of hydraulic oil in the short term and sometimes do not see any abnormalities, some will occur instability or rapid deterioration of the oil or pump wear, seriously affected the normal work and the main hydraulic system component life, thereby affecting product quality and production efficiency .
Ways to inspect hydraulic oil quality:
Water content
(1) visual method. If the oil was milky white haze like, it indicates oil contains large amounts of water
(2) combustion. Using clean, dry cotton or tissue stained with a little oil, then ignite cotton or tissue. If burst noise like "crack" flash spark, it indicates oil contains more water.
Impurities
(1) Direct identification. If there are obvious oil suspensions of metal particles, twist by fingers ,you can feel small particles; In light, if reflective flash, indicating hydraulic components has been severe wear. if sedimentation tank the bottom of the large metal scrap shows that the main pump or motor has been badly worn.
(2) filter paper test. For the higher viscosity of hydraulic oil, used pure gasoline diluted, and then filt oil by paper filter. If filter paper retained a large number of mechanical impurities (metal powders), indicating that hydraulic components are badly worn.
(3) sound and vibration to judge. If the hydraulic system has a large, intermittent noise and vibration, while the main pump has un-normal sound, even piston is crawling , then observe the oil tank, pipeline exit hole or level gauge, you will find a large number of bubbles. This shows that the hydraulic oil has been invaded a lot of air.
(4) heat detection. For low viscosity hydraulic oil, directly put hydraulic oil to clean, dry test tube and heating the tube. If has oil precipitate or suspended particles, it indicates the oil has been containing mechanical impurities.
3. Viscosity
(1) test tube inversion method. Put ready tested hydraulic oil and the standard oil into the same diameter and length glass test tube (do not overfill),plug two test tubes with cork. The two tubes placed side by side together, then the two test tube upside down at the same time quickly. If the measured hydraulic oil has more bubble in the tube,means low viscosity oil than the standard.
(2) Glass tilt method. Put ready tested Hydraulic oil with the new oil to the same horizontal glass plate, and then tilting the glass and observe flow rate .If flow speed is quick than the standard large, it indicates its low viscosity oil than the standard; the contrary, it indicates the viscosity of oil than the standard high.
Whether the deterioration of oil
(1) Tank out a little oil, filter with filter paper and, if left black residue on the filter paper as well as an assassination nose of the smell, it indicates that the oil has oxidized; You can also removed directly from the tank bottom part of the precipitation sludge, if found many deposits of asphalt and resin, just squeeze the twist on the fingers, if felt much gum, adhesion strength, it indicates that the oil has oxidized.
(2) Take few oil from the pump tank, if found that has shown a white color (sometimes, like yellow milk), and identification with the combustion method, and found that it contains large amounts of water, hand-feel has lost its stickiness , it indicates that oil has been thoroughly emulsified |
