
The quality of hydraulic oil not only influences the normal operation of
Engineering machinery, but also causes serious damage to hydraulic system
components. Now combined with work practice, several methods for simply
identifying the quality of hydraulic oil without special inspection (inspection
and testing) equipment are summarized.
1 Identification of hydraulic oil moisture content
(1) Visual inspection method: If the oil is milky white and turbid, it
means that the oil contains a lot of water.
(2) Combustion method: Dip a small amount of oil to be tested (inspected
and tested) with clean, dry cotton yarn or tissue paper, and then ignite it with
fire. If you find a "crack" popping sound or flashing phenomenon, it means that
the oil contains more water.
2 Identification of impurity content in hydraulic oil
(1) Sensory identification: There are obvious suspended metal particles in
the oil, and the presence of fine particles can be directly felt when kneading
with your fingers; if there is a reflective flash point under light, it means
that the hydraulic components have been severely worn; if A large amount of
metal chips deposited on the bottom of the fuel tank indicates that the main oil
pump or electric motor and engine have been severely worn.
(2) Heating identification: For hydraulic oil with lower viscosity, it can
be directly put into a clean and dry test tube to heat up. If precipitation or
suspended matter is found in the oil in the test tube, it means that the oil
contains mechanical impurities.
(3) Filter paper identification: For hydraulic oil with higher viscosity,
it can be diluted with pure gasoline and then filtered with clean filter paper.
If a large amount of mechanical impurities (metal powder) are found on the
filter paper, it means that the hydraulic components have been severely
worn.
(4) Sound identification: If the entire hydraulic system has large and
intermittent noise and vibration, and the main oil pump makes a "buzzing" sound,
or even the phenomenon of "crawling" of the piston rod, observe the oil tank
liquid level at this time. A large amount of foam will be found at the outlet of
the tubing or the transparent level gauge. This condition (Condition) shows that
the hydraulic oil has been immersed in a large amount of air.
3 Identification of hydraulic oil viscosity changes
(1) Glass plate tilting method: Take a clean glass plate, place it
horizontally, and place a drop of the tested hydraulic oil on the glass, and at
the same time drop another drop of standard hydraulic oil (new hydraulic oil of
the same brand) next to it. Then tilt the glass plate and observe carefully: if
the flow rate and flow distance of the tested oil are larger than the standard
oil, it means that its viscosity is lower than that of the standard oil;
otherwise, it means that its viscosity is higher than that of the standard
oil.
(2) Glass bottle inversion method: Put the tested hydraulic oil and
standard oil in two transparent glass bottles of the same size and length (do
not fill them too full), and then use the stopper to put the two bottles The
mouth is blocked. Place the two bottles side by side, and then quickly turn them
upside down at the same time. If the bubbles of the tested hydraulic oil in the
bottle rise faster than the bubbles of the standard oil in the bottle, it means
that the viscosity of the oil is lower than that of the standard oil, otherwise,
it means that the viscosity of the oil is higher than that of the standard oil;
If the rising speeds of the bubbles of the two oils are similar, the viscosity
is also similar.
4 Identification of hydraulic oil quality changes
(1) Identification of oil pump oil: Take out a small amount of tested oil
from the oil pump. If it is found to be milky white and turbid (sometimes like
light yellow milk), and when it is identified by the combustion method, it is
found to contain a lot of water. The feel of the hand has lost its stickiness,
indicating that the oil has been thoroughly emulsified and deteriorated and
should not be used again.
(2) Identification of the oil in the fuel tank: Take out a small amount of
the tested oil from the fuel tank and filter it with filter paper. If there is a
black residue on the filter paper and there is a pungent odor, it means that the
oil has been oxidized If it deteriorates, you can also take out part of the
precipitation sludge directly from the bottom of the fuel tank. If you find a
lot of asphalt and gum deposits in it, put it on your fingers and pinch it
(niǎn). If you feel that there is more gum, it has strong adhesion. , It means
that the oil has been oxidized and deteriorated. Abstract: Introduced the
troubleshooting process of a hydraulic oil staining fault, and formulated
measures to prevent the recurrence of this fault. During the lowering of the
H3/36B construction tower crane, the third During the operation of the stroke,
the hydraulic cylinder suddenly failed to lift, and the piston rod had only a
very slight extension action.
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