Humidification using ultrasound
The application of humidifiers ensures optimum humidity values in the room and can help to prevent colds, irritated eyes and dry skin. But how does this even work – how is the air moisturized by means of ultrasound?
Unlike cold evaporation humidifiers or rotational humidifiers that humidify dry room air by blowing it through a filter fleece enriched with water, ultrasonic humidifiers atomize water directly to produce an ultra-fine spray mist, which is why they are often referred to as atomizers or nebulizers.
Ultrasound procedure with an unheard-of efficiency
Water is next to incompressible and makes for a very poor pressure absorber. You may have noticed this watching a glass of water positioned on a speaker. Turning up the volume the water begins to ripple. In a way, the water surface "dances" to the beat and so renders the sounds visible in form of waves. A high-pitched note connotes a high frequency as can be seen from the higher wave. The ultrasonic humidifier takes advantage of this principle. A piezoelectric transducer converts electric energy to mechanical energy. An ultrasonic transducer located at the bottom of the water tank uses high-frequency sound to generate high pressure surges which then release tiny air bubbles (cavitation). The simultaneously triggered pressure waves entrain these bubbles and carry them off to the surface where a water column is created above the transducer. The bursting of these bubbles at the surface of the water column results in ultrafine mist droplets with a diameter of approx. 1 µm which can be absorbed by the air particularly fast.
This entire process is repeated over and over at incredible speed. With approx. 1.8 MHz the ultrasound frequency lives up to its name and is no longer audible for human ears – hence this noiseless procedure can be used for an agreeable, quiet atmosphere. This truly sets the water in motion for 1.8 MHz mean that 1.8 million oscillation cycles are transferred to the water each second! As a result minuscule cavities are formed at the water surface and ultrafine mist droplets are released from the wave crest.
Clean, humidified air – as a matter of hygiene
Ultrasonic technology is tried and tested and has been successfully applied in a variety of fields for many years now – whenever the humidity level had to be regulated with high precision and simultaneously low operating costs. Ultrasonic humidifiers are often accused of being unhygienic and of promoting an increased formation of germs in the water reservoir with the corresponding spread by way of atomization. It's a fact that water stagnating in containers leads to the formation of germs. In this respect, every water-filled device lacking the necessary care and maintenance tends to build up dirt regardless of the deployed humidification method.
For process-related reasons, however, ultrasonic humidifiers require a higher degree of discipline when it comes to hygiene. Here water is not evaporating, leaving potential germs behind in the container, instead the water is turned into mist using ultrasound and then emitted to the air. Even though the ultrasound already kills germs and bacteria, to permanently preserve the functionality of such devices in daily operation it is necessary to clean them regularly and thoroughly according to the manufacturer's instructions. Extended periods of water stagnation inside the tank must be prevented.
In order for ultrasonic humidifiers to operate hygienically, the water needs to be demineralized and ideally disinfected. Some devices come with integrated UV lamps for this purpose. Alternatively you may want to use a Secosan Stick to protect the water tank of the ultrasonic humidifier from germ infestation and bacterial growth on a permanent basis. Accessories When refilling water the stick can simply remain in the tank, its effect lasts six months without interruption.
Instead of using a Secosan Stick you can exchange the water every day (tap water must have been boiled first and then cooled down to room temperature, else you can use demineralized water).
Actually "distilled" water is ideal for use in an ultrasonic humidifier since the distillation – to a great extent – already cleans the water from salts, organic matter, micro-organisms and other contaminations which contributes to all hygiene-related efforts.
Unfortunately, truly distilled water, i.e. manufactured by distillation, is increasingly hard to obtain nowadays because in most cases the production is cheaper using ion exchangers. Water demineralized by means of ionization is often incorrectly referred to as "distilled water" and offered for use in car batteries and flat irons. However, this is no indication of it being free of germs unless the packaging bears the express declaration "suitable for medical purposes".
You will be much better off using decocted tap water and exchanging it daily. This saves you the purchase of expensive distilled water and is perfectly adequate from a hygienic point of view. Boiling not only kills most of the microorganisms and germs in the water, it also reduces the water's hardness which in turn significantly reduces scale build-up in the immediate surroundings of the device – even with an already installed decalcification cartridge.
Air – easy to breathe and optionally with a stimulating fragrance
Some ultrasonic humidifiers are additionally equipped with aroma diffusers. These models basically house two devices in one shell –humidifier and fragrance diffuser. An integrated scented oil tank permits the addition of an essential oil of your choice – revitalizing or relaxing. The on-demand fragrance diffuser atomizes the oil to an ultrafine spray which is evenly distributed in the room leaving nothing but a discreet scent. As such it is fairly predestined for aroma therapy stimulating men's own healing powers. The scent of essential oils affects our well-being and can be a natural remedy for stress, bad mood or even sleep problems. To make sure this agreeable room climate can be appreciated by all senses some ultrasonic humidifiers are further provided with an on-demand LED illumination as "wellness for the eyes".