Man B&W S50MC-C8-TII, Руководство по проекту, Страница: 342 / 403

MAN B&W 18.06
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MAN Diesel
MAN B&W MC/MC-C, ME/MEC/MEGI/ME-B engines 198 45 875.7
Drain Box for Fuel Oil Leakage Alarm
Any leakage from the fuel oil high pressure pipes
of any cylinder is drained to a common drain box
fitted with a level alarm. This is included for both
Attended Machinery Space (AMS) and Unattend-
ed Machinery Space (UMS).
Bearing Condition Monitoring
Based on our experience we decided in 1990 that
all plants, whether constructed for AMS or for
UMS, must include an oil mist detector specified
by MAN Diesel. Since then an Oil Mist Detec-
tor (OMD) and optionally some extent of Bearing
Temperature Monitoring (BTM) equipment have
made up the warning arrangements for prevention
of crankcase explosions on two-stroke engines.
Both warning systems are approved by the clas-
sification societies.
In order to achieve a response to damage faster
than possible with Oil Mist Detection and Bearing
Temperature Monitoring alone we introduce Bear-
ing Wear Monitoring (BWM) systems. By monitor-
ing the actual bearing wear continuously, mechani-
cal damage to the crank-train bearings (main-,
crank- and crosshead bearings) can be predicted
in time to react and avoid damaging the journal
and bearing housing.
If the oil supply to a main bearing fails, the bearing
temperature will rise and in such a case a Bear-
ing Temperature Monitoring system will trigger
an alarm before wear actually takes place. For
that reason the ultimate protection against severe
bearing damage and the optimum way of provid-
ing early warning, is a combined bearing wear and
temperature monitoring system.
For all types of error situations detected by the
different bearing condition monitoring systems
applies that in addition to damaging the compo-
nents, in extreme cases, a risk of a crankcase
explosion exists.
Oil Mist Detector
The oil mist detector system constantly measures
samples of the atmosphere in the crankcase com-
partments and registers the results on an opti-
cal measuring track, where the opacity (degree
of haziness) is compared with the opacity of the
atmospheric air. If an increased difference is re-
corded, a slow down is activated (a shut down in
case of Germanischer Lloyd).
Furthermore, for shop trials only MAN Diesel re-
quires that the oil mist detector is connected to
the shut down system.
Four alternative oil mist detectors are available:
Diagrams of the two of them are shown for refer-
ence in Figs. 18.06.01a and 18.06.01b.
Other Alarm Functions
4 75 161 Oil mist detector Graviner MK6.
Make: Kidde Fire Protection
4 75 163 Oil mist detector Visatron VN 215/93.
Make: Schaller Automation
4 75 165 Oil mist detector QMI.
Make: Quality Monitoring Instruments Ltd.
4 75 166 Oil mist detector MD-SX.
Make: Daihatsu Diesel Mfg. Co., Ltd.
4 75 167 Oil mist detector Vision III C.
Make: Specs Corporation