EVERDIGM EPG05, Руководство по эксплуатации и техническому обслуживанию

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7.4. Hydraulic oil
Generally speaking the hydraulic oil originally intended for the carrier can be also used in the hydraulic grab.
However, since working with the hydraulic grab will heat the oil much more than the usual excavation work,
the viscosity of the oil should be selected properly.
When the grab is used continuously, the temperature of the hydraulic oil normalizes at a certain level
depending on working conditions and on the carrier
‟s hydraulic system. At this temperature, the viscosity of
the hydraulic oil should be 15 ~ 100 cSt.
The hydraulic grab should not be started if the viscosity of the hydraulic oil is above 1000 cSt or operated
when the viscosity of hydraulic oil is below 15 cSt.
Following table shows hydraulic oils recommended for grab use.
Manufacturer Hydraulic Oil
TOTAL Total Equivis ZS46
SHELL Tellus Oil T32, T46
MOBIL Mobil DTE 13M, 16, 24
CALTEX Caltex HD Z46
ESSO Univis N32, N46
TEXACO Rando Oil 32S, 46
In summer and hotter climates, oils of viscosity class HLP 68 (68 cSt at 40
°
C) or higher should be used.
Using the oil with higher viscosity (too thick) may cause :

Generating shock while cylinder is in operation

Risk of failure in the pumps and rotation motor

Life time of hydraulic oil filter shortened
Using the oil with lower viscosity (too thin) may cause :

Efficiency losses (internal leaks)

Damage to seals and oil leaks

Accelerated wear in moving parts due to insufficient lubrication

Hydraulic oil purity
No separate filter is required when the hydraulic grab is installed in the carrier. The hydraulic oil filter of the
carrier will clean the oil flowing through the grab. The purpose of oil filter is to remove impurities from the
hydraulic oil since they cause accelerated component wear, blockages and even seizure. Impurities also
cause the oil to heat and deteriorate. Air and water are also impurities in oil. Not all impurities can be seen
with the naked eye.

Oil filter
In hydraulic grab work, the carrier
‟s oil filter must fulfill the following specifications:

The oil filter must allow maximum particle size of 25microns (0.025mm).

The oil filter material must be fiber cloth or very fine metallic mesh to withstand pressure fluctuations.

The oil filter must have a volume flow capacity of at least twice the grab
‟s maximum flow