BAC PCT Series, Руководство по эксплуатации и техническому обслуживанию

Страница: 32 / 38

26
W W W . B A L T I M O R E A I R C O I L . C O M . A U
M A R 1 0 8 - 2
Corrosion and Scale Control
1. To control corrosion and scale, maintain the water chemistry
of the re-circulating water within certain parameters. The
specific measures required vary from system to system and
are dependent on the chemistry of the make-up water, the
metallurgy of the piping and heat transfer devices exposed to the
re-circulating water and the temperatures at which the system
will be operating.
2. Bleed/blowdown, the continuous flow of a small portion of the
re-circulating water to drain, is used to control the concentration
of dissolved solids. On rare occasions, this may be adequate to
control scale and corrosion. More often, however, chemical scale
and corrosion inhibitors are necessary, which raise the allowable
level of dissolved solids without the risk of scale and corrosion.
3. Keep the chemically treated water within the guidelines given in
the below table. Your water treatment specialist may recommend
more conservative limits than those shown in the table.
Quality Guidelines for Chemically Treated Circulating Water.
Galvanised steel units require passivation in order to prevent white
rust. Refer to passivation on the following page. Hardness and
alkalinity limits may be exceeded under certain circumstances.
Consult your water treatment specialist for recommendations.
The conversion factor used to determine conductivity is 0.625
(TDS=0.625* Conductivity).
SST ZAM / Galvanised Steel
PH 6.5 to 8.5 7.0 to 9.0
Hardness as CaCO3 300 to 500 ppm 300 to 500 ppm
Alkalinity as CaCO3 500 ppm max. 500 ppm max.
Total Dissolved Solids 1200 ppm max. 1000 ppm max.
Chlorides 250 ppm max. 125 ppm max.
Sulphates 250 ppm max. 125 ppm max.
Table 2. Recirculated Water Quality Guidelines