How
to remove oil stain from diesel generator set?
All parts of diesel generator that come into contact with various oils must be cleaned of oil
after disintegration. Oil can be divided into two categories: saponifiable oil,
which is oil that can interact with strong alkali to produce soap, such as
animal oil and vegetable oil; and a type of oil that is not saponifiable, which
cannot work with strong alkali, such as various mineral oil, lubricants,
vaseline and paraffin. They are not soluble in water, but are soluble in
organic solvents. These oils are removed mainly by chemical and electrochemical
methods. Common cleaning solutions include organic solvents, alkaline solutions
and chemical cleaning solutions. There are two methods of cleaning: manual and
mechanical.
1.
Cleaning solution
(1)
Organic solvent
Common are kerosene,
light diesel, gasoline, alcohol and trichloroethylene. Organic solvent oil
removal is based on dissolving dirt, it has no damage to metal, can dissolve
all kinds of grease, does not require heating, easy to use, good cleaning
effect. However, most of the organic solvents are flammable, and the cost is
high, which is mainly suitable for small-scale units and scattered maintenance
work.
(2)
Alkaline solvent
It is an aqueous
solution of alkali or alkaline salt. The alkaline solution is used to
chemically react with the saponifiable oil on the surface of the part to
generate soap that is easily soluble in water and glycerin that is not easy to
float on the surface of the part, and then washed with hot water to easily
remove oil.
In the case where
unsaponifiable oil and saponifiable oil are not easy to remove, an emulsifier
should be added to the cleaning solution to emulsify the oil and separate it
from the surface of the part. Commonly used emulsifiers are soap, water glass
(sodium silicate), and gum. Different cleaning fluids should be used to clean
parts of different materials. Alkaline solution has different corrosion effect
on metal, especially on aluminum.
When cleaning with an
alkaline solution, the solution is generally heated to 80 ~ 90°C. Rinse with
hot water after degreasing to remove residual alkali solution on the surface to
prevent parts from being corroded. Alkaline solution cleaning is widely used.
(3)
Chemical cleaning fluid
It is a chemically
synthesized water-based metal cleaning agent, which is mainly used as a
surfactant. Because its surface active substances reduce interfacial tension
and produce wetting, penetrating, emulsifying and dispersing, etc., have strong
decontamination ability. It also has the advantages of non-toxic,
non-corrosive, non-combustible, non-explosive, non-pollution, having certain
anti-rust ability and low cost.
2.
Cleaning method
(1)
Scrubbing
Place the parts in a
container containing diesel, kerosene or other cleaning fluids, scrub with
cotton yarn or brush. This method is easy to operate, simple equipment, but low
efficiency, and is used for small and medium-sized parts produced in small
batches. Under normal circumstances, gasoline should not be used, because it
has fat-solubility, which will damage human body and easily cause fire.
(2)
Boiling cleaning
Place the prepared
solution together with the parts to be cleaned into a cleaning tank of
appropriate size welded with steel plate. A heating stove is arranged at the
lower part of the pool, and the parts are heated to 80-90°C for washing.
(3)
Spray rinsing
Spray the cleaning fluid
with a certain pressure and temperature onto the surface of the part to remove oil.
This method has good cleaning effect and high efficiency, but the equipment is
complex, and it is suitable for cleaning parts with less complicated shape and
serious oil dirt on the surface.
(4)
Vibration cleaning
It is to place the
cleaned parts on the cleaning basket or cleaning rack of the vibration cleaning
machine, immerse it in the cleaning liquid, simulate the artificial rinsing
action by the vibration of the cleaning machine, and cooperate with the
chemical action of the cleaning liquid to achieve the purpose of removing the
oil contamination.
(5)
Ultrasonic cleaning
It achieves the purpose
of removing oil stain of the parts by the combination of the chemical action of
the cleaning solution and the ultrasonic oscillation effect introduced into the
cleaning solution.
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