AHU Electrodes Humidifier - VEH
20.2.EN
6
Elsteam S.r.l - via E. Fermi, 496 - 21042 Caronno Pertusella (va) - Tel.+39 02 9659890 - Fax +39 02 96457007
E-mail: [email protected] - Web: http://www.elsteam.com
On one side of the kettle (the easiest to access once installed) you have the body of hydraulic manage-
ment of the system:
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Maximum water level sensor
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Draining bloc
The draining bloc has been specially designed to empty the tank from water
and limestone pieces without having to block and having to be able to work
without pressure.
It is essentially constituted by a valve having a free passage of 32 mm in di-
ameter, closed by a damper operated by an electric motor and a cam. Grafted
rigidly on the pivot motor is an electronics rotation sensor, which, communi-
cating with the microprocessor control is able to manage the correct opera-
tion of the system and communicate any faults that appear in the display.
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Working Principle
At power the humidifier performs a complete cleaning of tank for cleaning the electrodes. This phase is
followed by a total emptying of water eventually contained inside the kettle, so as to secure an operation
with hygienically perfect water. The humidifier performs a current control in the electrodes to ensure
that the kettle is totally empty. In case presence of current is detected, control system will signal the
"clogged drain" alarm. If the humidistat requires production to the humidifier, the electronics inserts
the power control system and starts to fill the kettle with water to continue with the production phase.
The conductivity of the water varies a lot, not only depending on the hardness of the water itself, but also
on the temperature: cold water is poorly conductive, and its conductivity increases with temperature up
to a maximum of around 95°C before falling back slightly at boiling point. It is a good practice that the
electronics manages current values when the water is close to boiling to compare realistic values of
steam production.
At this point, the humidifier will start filling water at short intervals until reaching a production equal to
the required one.
Following, the control system will keep production at set values with programmed fill or drain of water.
If the production exceeds the required value or the maximum supplied by the setting, the control system
will start to choke the power, taking care, however, that the average value of the output current is al-
ways zero, to avoid excessive corrosion of the electrodes.
At regular intervals, the humidifier makes also small purges, so as to ensure that the salt content in the
water is not too high and thus avoiding an excessive deposit of limestone.
At much longer intervals (default value 4h) the control system will make complete draining of the boiler
to remove limestone deposits.
Picture 2 - Cover with slits for steam outlet
