Design; Functional Description; Working Principle; Humidity Control - Helios HygroBox KWL Series Installation And Operating Instructions Manual

5 Design

1. Water tank
2. Drive motor
3. UVC pipe for disinfection
4. Sensor plate with a temp. and humidity sensor
5. Water inlet valve
6. Ballast unit for UVC pipe
7. Reverse osmosis membrane
(one unit required for KWL HB 250, two units required
for KWL HB 500)
8. Outlet pump
9. Electronic control system
10. Main board
11. Bladed rotary evaporator
12. Warm water heater battery (air side)

6 Functional description

Working principle

6.1
The HygroBox works on the natural evaporation principle
and ensures a constant relative air humidity, adjustable in
the range from 40 % to 60 % relative humidity. The unit
works automatically and the humidity is electronically
monitored in the device. Thus, the indoor air cannot be
over-humidified.
The humidification unit KWL HB 250 is dimensioned for a
maximum operating air volume flow of 250 m³/h, and the
KWL HB 500 is dimensioned for a maximum operating air
volume flow of 500 m³/h.
The water tank is supplied with drinking water from the
central water supply. Based on the evaporative power, a
maximum of 2.5 litres of water, which is continuously
placed, is located in the tank for KWL HB 250 and a
maximum of 15 litres of water for KWL HB 500.
The maximum filling level is limited using a floating switch
and mechanical overflow. The water in the tank is
continuously disinfected using UVC light, whereby the
UVC pipe illuminates the complete water tank and
evaporation surface. The UVC pipe has a radiant power of
4.3 watt at a wavelength of 253.7 nm. For safety reasons,
the UVC pipe is monitored by UV diode. This monitoring
process can detect a failure, contamination or line
breakage in the disinfection unit.
If the radiant power is too low, the water is drained and an
error message is output. The unit is automatically shut
down in case the UVC pipe malfunctions.
To prevent deposits during operation, especially scale
deposits on the bladed rotary evaporator and the water
tank, the standard version of the humidification unit is
equipped with a reverse osmosis unit. In the standard
design, the reverse osmosis unit is integrated into the
water inlet pipe between the solenoid valve and the water
tank.
A prefiltering unit for the water supply, which should be
installed during the course of mounting, is included in the
scope of delivery.
As an additional safety measure, the water is drained and
an error message output in case of the air humidity is
exceeded by more than 25% of the reference value of the
water for longer than 25 hours.

Humidity control

6.2
The air humidity is controlled through the water moistened
surface of the bladed rotor and the water level in the tank,
respectively. As the water level rises, the rotor blades are
submerged more deeply into the water, leading to a
greater wet surface area across the blades. The passing
airflow absorbs moisture from the wet blades, in
accordance with a specific reference value that is set as a
constant. However, as a rule the set relative humidity is
converted to the relevant absolute humidity at 21 °C
(factory setting) and then controlled.
Measured
temp.
Controlled humidity
Set humidity
8