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HUMIDIFIRST
PRINCIPLES OF ULTRASONIC HUMIDIFIERS
Ultrasonic humidifiers vibrate a water mist into the air by using piezoelectric crystals
(transducers). The transducers are mounted in a pan of water approximately 1.5 inches
deep. Each transducer is approximately the size of a nickel and vibrates at approximately
1.6 megahertz, a speed so fast that the water above the crystal cannot follow the speed of
the transducer, causing the water to cavitate. This process emits very small water
droplets into the air, approximately one micron in diameter (similar in size to steam
droplets). The water droplets are so small that they evaporate almost immediately.
The water feeding an ultrasonic humidifier must be pure so that minerals and other
contaminates are not vibrated into the air. Such purity is achieved with de-ionized (DI)
water filters to remove all minerals and foreign matter from the water. DI water offers
additional benefits. It assures a pure, healthy mist for those
breathing the air, and it significantly reduces the amount of maintenance required for the
humidifier, i.e. no scaling or sludge to be removed from the humidifier pan.
