Hydraulic Oil Back-Flushing; Alternative Design For The Back-Flushing Servo Oil Drain Tank - Man B&W S80ME-C7 Project Manual

MAN B&W
Hydraulic oil backflushing
The special suction arrangement for purifier suc-
tion in connection with the ME engine (Integrated
system).
The back-flushing oil from the self cleaning 0 µm
hydraulic control oil filter unit built onto the engine
is contaminated and it is therefore not expedient
to lead it directly into the lubricating oil sump tank.
The amount of back-flushed oil is large, and it
is considered to be too expensive to discard
it. Therefore, we suggest that the lubricating
oil sump tank is modified for the ME engines in
order not to have this contaminated lubricating
hydraulic control oil mixed up in the total amount
of lubricating oil. The lubricating oil sump tank is
designed with a small 'back-flushing hydraulic
control oil drain tank' to which the back-flushed
hydraulic control oil is led and from which the lu-
bricating oil purifier can also suck.
This is explained in detail below and the principle
is shown in Fig. 8.08.0. Three suggestions for the
arrangement of the drain tank in the sump tank
are shown in Fig. 8.08.02 illustrates another sug-
gestion for a back-flushing oil drain tank.
The special suction arrangement for the purifier is
consisting of two connected tanks (lubricating oil
sump tank and back-flushing oil drain tank) and
of this reason the oil level will be the same in both
tanks, as explained in detail below.
The oil level in the two tanks will be equalizing
through the 'branch pipe to back-flushing oil drain
tank', see Fig. 8.08.0. As the pipes have the
same diameters but a different length, the resis-
tance is larger in the 'branch pipe to back-flushing
oil drain tank', and therefore the purifier will suck
primarily from the sump tank.
The oil level in the sump tank and the back-flush-
ing oil drain tank will remain to be about equal be-
cause the tanks are interconnected at the top.
When hydraulic control oil is back-flushed from
the filter, it will give a higher oil level in the back-
flushing hydraulic control oil drain tank and the
purifier will suck from this tank until the oil level is
the same in both tanks. After that, the purifier will
suck from the sump tank, as mentioned above.
MAN B&W ME/ME-B/MEC/MEGI engines, ME Engine Selection Guide
This special arrangement for purifier suction will
ensure that a good cleaning effect on the lubrica-
tion oil is obtained.
If found profitable the back-flushed lubricating oil
from the main lubricating oil filter (normally a 50 or
40 µm filter) can also be returned into the special
back-flushing oil drain tank.
Fig. 8.08.01: Backflushing servo oil drain tank
Fig. 8.08.02: Alternative design for the
backflushing servo oil drain tank
MAN Diesel
8.08
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178 52 496.1
178 52 518.1
198 48 297.2