Pollution Of A Fluid; Where Does Solid Pollution Come From - Etesia HYDRO 124D Technical Training Manual

POLLUTION OF A FLUID

The NAS standard, the American standard, is used to describe how polluted a fluid is.
The table below indicates the number of particles in a given size range. 14 classes are thus
defined.
Size of
Class
particles
µm
00 0 1
125 250 500
5-15
22 44 89
15-25
4 8 16
25-50
50-100 1 2 3
0 0 1
>100
Class 9 oil is recommended for the Hydro 124 D.

WHERE DOES SOLID POLLUTION COME FROM ?

- Original pollution : these are particles present in the circuit at the time it is made
(absence of degreasing or failure to remove of carbon deposits from the metal parts in
contact with the hydraulic fluid), particles which have penetrated the components due
to poor storage (orifices not closed, component oil sumps containing no oil) and an
absence of depollution on commissioning (passage of a fluid filtered at 10 µm through
the different components).
- External pollution : these are pollutants that penetrate from the outside into the inside
of the circuit.
The mains places where external pollution can get in are :
- The breather of the hydraulic tank is a device that allows the maintaining of the
atmospheric pressure above the oil level. On the Hydro 124D, the breather is equipped
with a 10 µm air filter. This filter must be replaced regularly (see maintenance table).
- Ram rod seals : on the Hydro 124D a cartridge of the oil is placed on the oil return
circuit to avoid spreading the pollution to other components.
- Pump shaft and wheel motors seals : the oil is drained by an external drain (because
of the external leakage) and is returned to the tank via the oil filter.
- Addition of oil : as far as possible use a filtering unit when topping up with oil. ETESIA
offers a filtering unit under the reference number 29977.
-
2 3 4 5
1000 2000 4000 8000
178 356 712 1425
32 63 126 253
6 11 22 45
1 2 4 8
6 7 8 9
16000 32000 64000 128000
2850 5700 11400 22800
506 1012 2025 4050
90 180 360 720
16 32 64 128
10 11 12
256000 512000 1024000
45600 91200 182400
8100 16200 32400
1440 2880 5760
256 512 1024
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