SPX Cooling Technologies none Manual De Usuario

18

The steel used in MC Fluid Cooler's has been galvanized with a heavy
zinc coating averaging 2.0 mils in thickness. Other materials used (PVC
drift eliminators, bearing, belts) are selected to offer maximum service life 
in a “normal” fluid cooler environment, defined as follows:

Recirculating water with a pH between 6.5 and 8; a chloride content (as 
NaCl) below 500 ppm; a sulfate content (SO4) below 250 ppm; total al-
kalinity (as CaCO

3

) below 500 ppm; calcium hardness (as CaCO

3

) above 

50 ppm; no significant contamination with unusual chemicals or foreign
substances; and adequate water treatment to minimize scaling.

•  Startup Conditions: The water conditions during initial fluid cooler op-

eration are crucial in preventing premature corrosion of galvanized steel 
(white rust). For at least the first eight weeks of operation, pH should 
be controlled between 6.5 and 8.0 with hardness and alkalinity levels
between 100 and 300 ppm (expressed as CaCO

3

).

•  Chlorine (if used) shall be added intermittently, with a free residual not

to  exceed  1  ppm—maintained  for  short  periods.  Excessive  chlorine 
levels may deteriorate sealants and other materials of construction.

•  An atmosphere surrounding the tower no worse than “moderate indus-

trial”, where rainfall and fog are no more than slightly acid, and they do 
not contain significant chlorides or hydrogen sulfide (H

2

S).

•  Many proprietary chemicals exist for control of scale, corrosion, and

biological growth and should be used prudently. Also, combinations 
of chemicals may cause reactions which reduce treatment effective-
ness, and certain chemicals such as surfactants, biodispersants and 
antifoams may increase drift rate.