Maintenance, Belt tensioning – SPX Cooling Technologies MARLEY AV 98-1514E User Manual
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concentrations. This stabilization of contaminant concentrations is usually
accomplished by blowdown, which is the constant discharge of a portion of
the circulating water to waste. As a rule, acceptable levels on which to base
a treatment schedule will be in the range of 2-4 concentrations. The following
table shows the minimum amount of blowdown (percent of flow) required
to maintain different concentrations with various cooling ranges*:
* Range = Difference between hot water temperature coming to tower and cold water
temperature leaving tower.
EXaMPLE: 700 GPM (44.2 L/s) circulating rate, 18°F (10°C) cooling range.
To maintain 4 concentrations, the required blowdown is 0.458% or .00458
times 700 GPM (44.2 L/s), which is 3.2 GPM (0.2 L/s).
If tower is operated at 4 concentrations, circulating water will contain four
times as much dissolved solid as the makeup water, assuming none of the
solids form scale or are otherwise removed from the system.
When water treatment chemicals are added, they should not be in-
troduced into the circulating water system via the cold water basin
of the cooling tower. Water velocities are lowest at that point, which
results in inadequate mixing.
Belt Tensioning
The belts are adjusted by turning the jacking screw at the motor support.
Ideal tension is the lowest tension at which the belt will not slip under
peak load conditions. Check tension frequently during the first 24-48
hours of run-in operation. Overtensioning shortens belt and bearing
life. Keep belts free from foreign material which may cause slip. Never
apply belt dressing as this will damage the belt and cause early failure.
A Dodge
®
V-Belt Tension Tester is an alternate method for tensioning
V-belts. Check with you local belt supplier.
Maintenance
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