AERMEC TRA Manuel Technique page 14

must be connected to them.
Precautions to be tank:
- interpose the gasket supplied between
the flanged water inlet attachment and
the piping entering the system.
- it is good practice to insert an
expansion or anti-vibration joint made
of rubber between the water inlet
flange and the piping entering the
system.
- do not allow the weight of the piping
entering the system (generally made
of iron and full of water) to weigh on
the flange of the tower, but install an
adequate support bracket.
- do not do up the bolts joining the water
inlet to the piping arriving at the plant
too tightly: as this is made of plastic, it
might break if tightened up to tightly..
In the tank of the tower there are cooled
water inlet attachments that must normally
be connected with the pump sending
water to the users.
To avoid leaks from the drainage
attachment, you are advised to position
the rubber gasket on the outside of the
tank where is a smooth surface that can
guarantee the grip; the gasket positioned
inside the tank does not guarantee
tightness in the case of a rough surface.
For correct installation, follow the
instructions below considering that the
walls of the tower will remain fixed
between the butyl gasket (2) and the one
made of rubber (3) (Fig. 10).
The drainage attachment must therefore
be tightened using a special compasses
style spanner. The tank also contains:
- the overflow connection and the bottom
drain that must be connected to the
sewer system drainage piping.
- the connection to which the automatic
evaporated or bled water replacement
ball cock is attached.
All the connections mentioned above
have gas threads (male threading), with
the exception of the drainage attachment
that is always flanged unless requested
differently.
Top up water treatment.
Cooling is by means of the evaporation of
a certain amount of water in circulation
14
in accordance with a precise physical law
and volumes that depend on the amount
of heat to be eliminated. The water that
evaporates has a very low salt content that
increases its concentration in the cooling
circuit however until it reaches saturation
point and is deposited inside both the
piping and on the exchange pack meaning
that the entire system fails to operate
properly.
It is therefore fundamental to treat the
top up water before it is sent into the
cooling circuit by means of the floating
valve in addition to carrying out bleeds
preferably managed through the automatic
monitoring of water hardness.
The type of treatment cannot be
standardised and be applied in all
situations but it depends strictly on the
nature of the water available for carrying
out the top up. By way of example, the
general characteristics that the top up
water for cooling circuits must have are
shown below:
NATURE: physically clean, clear in
appearance without clouding, without
HARDNESS: carbonatic max. 14°F (140 [mg / l] of CaCo
CONDUCTIBILITY': electrical max. 600 [µs (Microsiemens) / cm]
SPECIFIC VALUES:
pH 0 = 7.8
pH 0 = 8.1
pH 0 = 8.3
Free carbonatic acid max 8 mg/l
Free carbonatic acid max 4 mg/l
Free carbonatic acid max 3 mg/l
Ammoniac not present
Iron max 0.3 mg/l
Manganese max 0.05 mg/l
Sulphates max 250 mg/l
Chlorides max 150 mg/l
Kmn04 max 15 mg/l
Key::
1. Flange : on the drain is optional
standard on the water inlet.
2. Butyl gasket
3. Rubber gasket
4. Fixing ring nut
deposits and chemically neutral.
SAFETY PRECAUTIONS! Bleeding with
or without chemical anti-chalk or anti-
corrosion treatment is not enough to
control biological pollutants. The growth
of algae, mud or other microbodies, if
not controlled will reduce the system's
yield and may contribute to the growth
of potentially damaging microbodies in
the water system. .
For this reason a treatment programme
using biocides specifically designed for
biological control must be implemented
right from the first time the system is
loaded with water and monitored
systematically in accordance with
the competent specialised supplier's
instructions.
N . B. : Pe r s o n n e l e n g a g e d i n t h e
maintenance of the tower are advised to
follow the instructions in the EUROVENT
9-5 guide (2nd edition 2002) so as to
prevent biological contamination in
evaporation cooling systems..
3
)
Carbonatic hardness14° F
Carbonatic hardness10° F
Carbonatic hardness 7° F
Carbonatic hardness 14° F
Carbonatic hardness 10° F
Carbonatic hardness 7° F
fig.10