Man L23/30DF, Project Manual

Page: 265 / 392

Water washing of turbine side
The necessary water flow is depending on exhaust
gas flow and temperature. E.g. the flow needed for
L16/24 is from 2 - 5 litres per minute for 5 and 9
cylinder engines. The water flow must be so high
that all of the water do not evaporate. Also the
waterflow must not be so high that the turbine
wheel is drowned and stops rotating. The washing
sequence should be in accordance with the turbo-
charger manual. Engine load, exhaust gas tempera-
ture before turbine and turbine speed must be
according to turbocharger manual. Carry out
sequential washing so that exhaust gas tempera-
ture after turbine drops below 100°C and in the dry-
ing period increases to more than 100°C. For pre-
adjustment of the washing tool, install the correct
orifice for the actual engine size, check that the
water flow is in accordance with the table by adjust-
ing the water pressure. Check in a bucket that the
water flow is in the correct range.
Water flow
l/min
Diameter orifice
mm
5-9L16/24 2-5 2.5
5-9L21/31 5-10 3.5
5L27/38 (NR20/S)
5-6L27/38 (TCR18)
7-11 3.5
6-8L27/38 (NR24/S)
7-9L27/38 (TCR20)
10-15 4.5
5-6L23/30H
5-6L23/30H Mk2
2-5 2.5
7-8L23/30H
7-8L23/30H Mk2
4-7 3.5
5-6L28/32H 5-10 3.5
7-9L28/32H 7-11 3.5
12V28/32S 5-10 3.5
16-18V28/32S 7-11 3.5
Experience has shown, that washing at regular
intervals is essential to successful cleaning, as
excessive fouling is thus avoided. Washing at inter-
vals of 150 hours is therefore recommended.
Depending on the fuel quality these intervals can be
shorter or longer. However, the turbine must be
washed at the latest when the exhaust gas temper-
ature upstream of the turbine has risen about 20° C
above the normal temperature.
Heavily contaminated turbines, which where not
cleaned periodically from the very beginning or after
an overhaul, cannot be cleaned by this method.
If vibration in the turbocharger occur after water-
washing has been carried out, the washing should
be repeated. If unbalance still exists, this is presum-
ably due to heavy fouling, and the engine must be
stopped and the turbocharger dismantled and man-
ually cleaned.
The cleaning effect is based on the water solubility
of the deposits and on the mechanical action of the
impinging water droplets and the water flow rate.
The washing water should be taken from the fresh
water system and not from the fresh cooling water
system or salt water system. No cleaning agents
and solvents need to be added to the water.
To avoid corrosion during standstill, the engine
must, upon completing of water washing run for at
least 1 hour before stop to insure that all parts are
dry.
MAN Diesel & Turbo
3700418-8.1
Page 5 (6)
Cleaning the turbocharger in service - turbine side
B 16 01 3
L28/32DF, V28/32S, L28/32S, L28/32H, L27/38S, L27/38, L23/30DF, L23/30S,
L23/30H, L21/31S, L21/31, L16/24S, L16/24
2017.01.24