Kalmar DCE80-100E, Техническое руководство

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All trucks
Technical Handbook
Hydraulic Cylinders
Service
9279 02-09
Publ.
Gr. S.
4 70
Gasses
The most common gas that occurs as an impurity in a hydraulic
system is air. Unlike fluids, gasses can be compressed. If air is
allowed to enter a hydraulic system, this compression will be ex-
perienced as a “sponginess” of operation, making hydraulic
movements difficult to control.
Air in the hydraulic fluid can also cause corrosion damage, par-
ticularly when localized, sudden reductions in pressure, known
as cavitation, occur.
Liquids
The most common liquid impurity that occurs in a hydraulic sys-
tem is water, for example, through condensation. This can cause
rust to form, resulting in flakes or particles of rust entering the
system. This most commonly occurs in the tank and those parts
that are above the level of the hydraulic fluid. Such parts can be
inside single action cylinders where the complete length of the
hydraulic piston stroke, is seldom or never used. One simple pre-
ventive measure for such parts is to regularly run all hydraulic
functions to their end positions so that the whole of the cylinders
are lubricated.
Measures to prevent pollution of the hydraulic
system
When changing attachments
Many machines have attachments that can be changed, which
also means that hydraulic lines and hoses must be loosened and
switched over. This entails a major risk of impurities penetrating
into the system.
z Always clean the connection point extremely thoroughly be-
fore disconnecting
z
If possible, use quick release connectors fitted with a non-re-
turn valve. This will then reduce the risk of impurities entering
the system and fluid being spilt
z
Clean the connectors extremely thoroughly before making the
connection. Make sure that no impurities are forced into the
connectors themselves.
When the system is operating
All protruding hydraulic components, such as hydraulic piston
rods, are at considerable risk from both mechanical damage and
impurities. Due to the fact that the level of hydraulic fluid in the
tank varies, the tank will “breath” through the breather filter and if
the level becomes too low, the hydraulic pump will fill the system
with air.
z
Be extremely careful with hydraulic piston rods so as to avoid
physical damage to them
z Regularly empty condensation water from the hydraulic tank
z Make sure that the fluid level in the hydraulic tank is always as
high as possible
z
Make sure that all filters in the system function correctly. Reg-
ularly replace filter elements, in accordance with the ma-
chine’s lubrication chart
z
Regularly check the wiper and rod seals and replace them as
required