MAN B&W 5L28/32H, Руководство пользователя

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08028-0D\H5250\94.08.12
A number of descaling preparations contain colour
indicators which show the state of the acid solution.
If the acid content is exhausted, a new acid solution
can be added, in which case, the weakest recom-
mended concentration should be used.
The solubility of acids in water is often limited.
Therefore if, in exceptional cases, a large amount is
required, descaling can be carried out in two stages
with a new solution of compound and clean water.
Normally the supplier will specify the maximum
solubility.
After completing the descaling, drain the system and
flush with water. Acid residues can be neutralized
with clean tap water containing 10 kg soda per ton of
water. Circulate the mixture for 30 minutes, then
drain and flush the system.
The cooling water system must not be put under
pressure.
Continue to flush until water used is neutral (pH
approx. 7).
B 13 00 0
1609571-3.4
Page 4 (5)
General
00.11
Freshwater System Treatment
Adding of Inhibitors
Fill up the cooling water system with water from the
evaporator to the lowest water level in the expansion
tank.
Weight out the quantity of inhibitors specified by the
supplier and dissolve in a clean iron drum with hot
water from the evaporator.
Add the solution via the expansion tank to the
system. Then fill up to normal water level with water
from the evaporator.
Allow the engine to run for not less than 24 hours to
ensure that a stable protection of the cooling surfa-
ces is formed.
Subsequently, test the cooling water with a test kit
(available from the inhibitor supplier) to ensure that
an adequate inhibitor concentration has been obtai-
ned.
This should be checked every week.
The acid content of the system oil is to be checked
directly after the descaling with acid, and again 24
hours afterwards.