Nordmann DC4 - Functional Description

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3.4 Functional description
The steam humidier Nordmann RC4/DC4 is a pressureless steam generator that utilizes an elec-
trode heating. The steam humidier Nordmann RC4/DC4 is designed for air humidication via a
steam distributor (unit versions Nordmann DC4) or via the integrated ventilation unit (unit versions
Nordmann RC4).
Steam generation
Any time steam is requested, the electrodes are supplied with voltage. Simultaneously, the inlet valve
opens and water enters the steam cylinder from the bottom via water cup and supply line. As soon
as the electrodes come in contact with the water, current begins to ow between the electrodes,
eventually heating and evaporating the water. The more the electrode surface is exposed to water,
the higher is the current consumption and thus the steam capacity.
Upon reaching the requested steam capacity, the inlet valve closes. If the steam generation de-
creases below a certain percentage of the required capacity, due to lowering of the water level (e.g.
because of the evaporation process or drainage), the inlet valve opens until the required capacity
is available again.
If the required steam capacity is lower than the actual output, the inlet valve is closed until the desired
capacity is achieved by lowering of the water level (evaporation process).
Level monitoring
A sensor provided in the steam cylinder cover detects when the water level gets too high. The mo-
ment the sensor comes in contact with water, the inlet valve closes.
Drainage
As a result of the evaporation process, the conductivity of the water increases due to an escalating
mineral concentration. Eventually, an inadmissibly high current consumption would take place if this
concentration process were permitted to continue. To prevent this concentration from reaching a
value, unsuitably high for the operation, a certain amount of water is perio dically drained from the
cylinder and replaced by fresh water.
Control
The steam production can be controlled steplessly via the internal or an external continuous controller
or with an On/Off control via an external humidistat.