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© 2018 Dehaco B.V. • Operation and maintenance manual IBEX Hydraulic breakers G-type – Version 17-08-2018
6. Maintenance
6.3 Hydraulic oil
ATTENTION!
Ø
When the breaker is used continuously, the
temperature of the hydraulic oil will normalize
at a certain level. At this temperature, the
viscosity of the hydraulic oil should be 20~40 cst
(2.90~5.35ºE)
Ø
The breaker may not be started if the viscosity
of the hydraulic oil is above 1000 cst (131ºE) or
operated when the viscosity of the hydraulic oil
is below 15 cst (2.35ºE).
Problems when the hydraulic oil is too thick:
◊ Difficult start up.
◊ Stiff operation.
◊ Breaker strikes irregularly and slowly.
◊ Danger of cavitation in the pumps and hydraulic
breaker.
◊ Sticky valves.
◊ Filter bypass, impurities in the oil will not be
removed.
Problems when the hydraulic oil is too thin:
◊ Efficiency losses (internal leaks).
◊ Damage to seals.
◊ Accelerated wearing of parts, because of
decreased lubrication efficiency.
Special oils
◊ Is some cases special oils (e.g. biological oils and
non-inflammable oil) can be used, please observe
following specifications when considering the use
of special oil:
-
The viscosity range in the special oil must
be in the given range of 15~1,000cSt
(2.35~131ºE).
Cleanliness of hydraulic oil
1) The hydraulic oil filter of the excavator will clean
the oil flowing through the breaker.
2) The purpose of the oil filter is to remove impurities
from the hydraulic oil (air and water are also
impurities in oil).
3) Impurities also cause the oil to overheat and
deteriorate.
Oil filter
◊ The excavator oil filter must fulfill the following
specifications:
-
The oil filter must be rated at a maximum of
25 micron.
-
The oil filter must be a standard return line
filter rated to maximum working pressure.
-
The oil filter must have a volume flow capacity
of at least twice the breaker’s maximum flow.
-
The cooler must withstand a dynamic pressure
of 290 psi (20 bar).
-
If the excavator’s oil cooler is too small either
the original cooler must be replaced with
a larger one or an auxiliary cooler must be
installed.
The auxiliary hydraulic cooler can be installed:
◊ In front of the radiator, in which case an additional
fan is not required, ie. maximum rise of the
cooling air is 5ºC (40ºF).
◊ Any other suitable place, using a fan either
hydraulically or electrically driven.
Damage caused by hydraulic oil contamination
1) The working life of the pumps is significantly
shortened.
-
Premature wear of parts.
-
Cavitation.
2) Valves do not function properly.
-
Spools bind.
-
Premature wear of parts.
-
Blocking of small holes.
3) Wear of cylinders and gaskets
4) Reduced breaker efficieny.
-
Premature wear of moving parts and seals.
-
Danger of the piston seizing.
-
Oil overheats.
5) Shorten working life and reduced efficiency of
hydraulic oil.
-
Oil overheats.
-
Oil quality deterioration.
-
Electrochemical changes in hydraulic oil.