Ingersoll-Rand NIRVANA IRN75-160K-2S - Manual (Page 26)

IRN37 - 160K - CC & IRN50 - 200H -CC & IRN75 - 160K - 2S & IRN100 - 200H - 2S & IRN 250 - 300H - 2S
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2
7.0 INSTALLATION
Water quality recommendations
Water quality recommendations Water quality is often
overlooked when the cooling system of a water−cooled
air compressor is examined. Water quality determines
how effective the heat transfer rate, as well as the flow
rate will remain during the life of the unit. It should
be noted that the quality of water used in any cooling
system does not remain constant during the operation
of the system. Evaporation, corrosion, chemical and
temperature changes, aeration, scale and biological
formations effect the water makeup. Most problems in
a cooling system show up first in a reduction in the heat
transfer rate, then in a reduced flow rate and finally with
damage to the system.
Scale: Scale formation inhibits effective heat transfer, yet
it does help prevent corrosion. Therefore, a thin uniform
coating of calcium carbonate is desired on the inner
surface. Perhaps the largest contributor to scale formation
is the precipitation of calcium carbonate out of the water.
This is dependent on temperature and pH. The higher the
pH value, the greater the chance of scale formation. Scale
can be controlled with water treatment.
Corrosion: In contrast to scale formation is the problem
of corrosion. Chlorides cause problems because of their
size and conductivity. Low pH levels promote corrosion,
as well as high levels of dissolved oxygen.
Fouling: Biological and organic substances (slime)
can also cause problems, but in elevated temperature
environments such as cooling processes they are not a
major concern. If they create problems with clogging,
commercial shock treatment are available.
To ensure good operation life and performance of
the compressor cooling system, the recommended
acceptable ranges for different water constituents are
included below:
Cooling Water Analysis Chart
Substances Test interval Acceptable
concentration
Corrosivity
(Hardness,
pH, Total
Dissolved Solids,
Temperature at
inlet Alkalinity)
Monthly - if stable
for 3 to 4 months,
analyse quarterly.
Langelier Index
0 to 1
Iron Monthly <2 ppm
Sulphate Monthly <50 ppm
Chloride Monthly <50 ppm
Nitrate Monthly <2 ppm
Silica Monthly < 100 ppm
Desolated
Oxygen
Daily - if stable,
analyse weekly
0 ppm (as low
as possible)
Oil & Grease Monthly <5 ppm
Ammonia Monthly <1 ppm