Condair EL - Functional Description

10 Product Overview
3.2 Functional description
The Condair EL steam humidier is an atmospheric steam generator. It operates on the electrode heating
principle and is designed for direct room air humidication (with blower pack) and indirect humidication
(with steam distributor) in venti lating and air-conditioning systems.
Water supply
The water is supplied via a lter valve (accessory "Z261") to the steam humidier. It reaches the steam
cylinder via the inlet valve and the open ll cup.
Steam generation
Any time steam is requested, the electrodes are supplied with voltage via the main contactor. Simulta-
neously, the inlet valve opens and the water enters the steam cylinder from the bottom via the open ll
cup and lling hose. As soon as the electrodes come in contact with the water, current begins to ow
between the electrodes, generating heat and increasing the water evaporation rate. The more of the
electrode surface area that is exposed to conductive water, the higher the current consumption and thus
steam production.
Upon reaching the requested steam capacity, the inlet valve closes. If the steam generation decreases
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, detects when the cylinder water level is at the maximum. When
the sensor comes in contact with water, the inlet valve will close after a short delay.
Drainage
As a result of the evaporation and rell process, the conductivity of the water increases due to an escalat-
ing 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 via the internal or an external continuous Proportional (P)/
Proportional-Integral (PI) controller or with an On/Off control via an external humidistat.