1. Field of the Invention
The instant invention relates to ultrasonic cleaners and, more precisely, the instant invention relates to ultrasonic cleaners of the type, in which a liquid is ultrasonically agitated to clean articles immersed in the liquid.
2. Technical Considerations and Prior Art
The ability of a liquid when ultrasonically agitated to penetrate small spaces and, by cavitation, to remove foreign matter from solid objects has led to the wide use of ultrasonic cleaners in laboratories and industry. Frequently, it is not possible to clean or remove foreign matter by any other process.
The effects of ultrasonic energy on living organisms are not fully understood, Accordingly, it is important to avoid exposing users of ultrasonic cleaners and the like to direct contact with ultrasonic energy. When ultrasonic energy is used in physiotherapy, the treatment can only be performed under medical supervision. Consequently, it is important that any ultrasonic product, such as an ultrasonic cleaner, which may be for home use, have built-in safety features which will not permit the user to come into direct contact with an ultrasonically excited medium, such as the cleaning liquid which is used in ultrasonic cleaners.
Many domestic cleaning chores, done commercially by ultrasonics, such as the removal of plaque and calculus from dentures, removal of oxidation from silverware and jewelry, and the removal of rust from hand tools and small parts, could be done domestically. This, of course, has been recognized, and consumer ultrasonic cleaners have appeared on the market from time to time. However, these cleaners have not been successful, because in order to prevent possible injury to the user, the power output has to be kept so low that effective cleaning is not accomplished.
In an ultrasonic cleaner, suitable for domestic use, it is necessary that the cleaner be easy to operate and be pleasing in appearance, in addition to be safe. In this regard, the cleaner should be easy to fill with a cleaning liquid, such as water, and should fit in any decor.
Preferably, the domestic cleaner should be able to utilize existing ultrasonic driving circuits currently used in commercial cleaners, and yet have the aforementioned safety, ease of operation, and appearance.