ULTRASONIC
4
Copyright STULZ GmbH 02/1997
1.
Operation
STULZ Ultrasonic humidifiers operate on the principle of ultrasonic nebuliza-
tion. A 48 V a.c. voltage is rectified on an oscillator circuit and transferred into
a high frequency signal of 1.65 MHz. This signal is transmitted to an oscillator
(transducer) installed in the water bath, which then transfers this signal into
high frequency automatic vibrations. The built-in oscillators are so-called
thickness oscillators which in accordance with the signal of 1.65 MHz applied
change their thickness 1.65 million times per second.
The surface of the transducer oscilla-
tes at such a high speed that the
water cannot follow because of its
inertia of masses; therefore, imme-
diately after the unit has been swit-
ched on, a water column is genera-
ted above the oscillators. During the
negative amplitude of the oscillator,
an instantaneous vacuum is produ-
ced because of the fact that the
water cannot follow the faster oscilla-
tor movements. Cavitation produ-
ces bubbles, which are "catapulted"
to the edge of the water column du-
ring the course of the positive ampli-
tude and which collide there with
great force. During this procedure,
finest water particles are being ato-
mized at the edge of the water co-
lumn. Due to the focussing of the
sound waves, cross waves are pro-
duced directly underneath the water
surface, in the centers of which
smallest water droplets are separa-
ted and generate a mist, which is
immediately absorbed from the air
stream.
OPERATION