WÄRTSILÄ PAAE051728, Instruction Manual

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a) Mechanical cleaning
A great deal of the deposits consists of loose sludge and solid
particles which can be brushed and rinsed off with water.
On places where the accessibility is good, e.g. cylinder liners,
mechanical cleaning of considerably harder deposits is efficient.
In some cases it is advisable to combine chemical cleaning with
a subsequent mechanical cleaning as the deposits may have
dissolved during the chemical treatment without having come
loose.
b) Chemical cleaning
Narrow water spaces (e.g. cylinder heads, coolers) can be cleaned
chemically. At times, degreasing of the water spaces may be
necessary if the deposits seem to be greasy (see chapter 18.,
section 18.5).
Deposits consisting of primarily limestone can be easily re-
moved when treated with an acid solution. On the contrary,
deposits consisting of calcium sulphate and silicates may be hard
to remove chemically. The treatment may, however, have a cer-
tain dissolving effect which enables the deposits to be brushed off
if there is only access.
On the market there are a lot of suitable agents on acid base
(supplied e.g. by the companies mentioned in the end of chapter
02. See the list of approved cooling water additives and treatment
systems).
The cleaning agents should contain additives (inhibitors) to
prevent corrosion of the metal surfaces. Always follow the manu-
facturer’s instructions to obtain the best result.
After treatment, rinse carefully to remove cleaning agent re-
siduals. Brush surfaces, if possible. Rinse again with water and
further with a sodium carbonate solution (washing soda) of 5 %
to neutralize possible acid residuals.
19.3 Water pump
19.3.1 Description
The water pump is a centrifugal pump and is driven by the gear
mechanism at the free end of the engine. The shaft is made of acid
resistant steel, the impeller (6) of cast iron and the remaining
details of cast iron.
The shaft is mounted in two ball bearings (8) and (10), which are
lubricated by pressurized oil entering through the opening in the
bearing housing. The shaft seal (16) prevents the oil from leaking
out and, at the same time, dirt and leak water from entering.
The gear wheel (12) is fastened to the shaft by conical ring
elements (13). When the screws (14) are tightened, the rings exert
a pressure between the gear wheel and the shaft. Due to the
friction, the power from the gear wheel is transmitted to the pump
shaft.
19 Cooling Water System 32-200050
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