Ingersoll-Rand 100-200 HP/75-160 KW - Manual (Page 88)

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Recommended equipment for on-site analysis includes a
thermometer, pH meter, and dissolved oxygen meter.
Dissolved oxygen and temperature must be measured
on-site and it is recommended that pH be measured
on-site. All other analyses should be performed by a
professional water quality analyst. The Langelier Index
(Ll) is calculated using the following equation and the
tables found on the following pages.
Ll = pH - (9.30 + Total Dissolved Solids chart value +
Temperature chart value ) + Hardness chart valve +
Alkalinity chart value)
The Ll is zero when the water is in chemical balance. If
the Ll is greater than zero, there is a tendency to form
scale. If the Ll is less than zero, the water tends to be
corrosive.
Dissolved oxygen may be controlled in closed cooling
towers. Several types of treatments are commercially
available to remove dissolved oxygen. For open cooling
towers, dissolved oxygen is not an easily controlled
parameter. Also, a filtration system is recommended for
the water going into the air compressor when using an
open cooling tower.
It should be noted that Ingersoll-Rand’s guidelines and
recommendations should be used in evaluating the water
systems and the problems that may occur in the normal
operation of our air compressors. If water problems
persist or are not covered above, you should consult a
professional.