SPX Marley NCWD, Руководство пользователя

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4. With no heat load on the circulating water, icing cannot be controlled
effectively by air control during freezing weather. Towers must not be
operated with reduced water rate and/or no heat load during
freezing weather. If the circulating water system cannot be shut down,
water returning from the process should be made to bypass the tower. If
a bypass is used, all water must be bypassed without modulation. If the
water bypass is directly into the tower's cold water basin, its design must
be approved by SPX Cooling Technologies.
Intermittent Freezing Weather Operation:
If periods of shutdown (nights, weekends, etc.) occur during freezing weather,
measures must be taken to prevent the water in the cold water basin—and all
exposed pipework—from freezing. Several methods are used to combat this,
including automatic basin heater systems available from Marley.
The plume abatement coils on the Marley NCWD tower are equipped with
continuous drain down piping located in the lower corner of the coil oppo-
site the water inlet. The water in the coil will drain through the intermediate
distribution basin. This prevents the need to manually drain the coils during
tower shut down.
Unless some means of freeze prevention is incorporated into your
system, the tower basin and exposed pipework should be drained
at the beginning of each wintertime shutdown period.
If tower basin is drained, verify that all basin heaters have been shut
off either by automatic cutoff or disconnect switch.
It is recommended that you discuss your freeze prevention options with your
local Marley sales representative.
Water Quality and Blowdown
Maintaining Water Quality:
The steel used in NCWD towers has been galvanized with a heavy zinc
coating averaging 2.0 mils in thickness. The NCWD stainless steel option is
even more corrosion resistant than galvanized steel in certain environments.
Other materials used (PVC fill, drift eliminators, and louvers, aluminum fans,
cast iron Geareducer, etc.) are selected to offer maximum service life in a
“normal” cooling tower environment, defined as follows:
Caution
Warning
operation