Abstract: An ultrasonic oscillating device comprising a base plate and an ultrasonic transducer attached to the base plate. The thickness of the base plate is an integer multiple of approximately a half-wavelength of an oscillation of the base plate in the direction of its thickness under a driving frequency. The base plate may be a quadrilateral such as a square and a rectangle with a length of one side of the quadrilateral being at least a quarter-wavelength of the oscillation. The base plate may be a circle with a length of a diameter of the circle being at least a quarter-wavelength of the oscillation. An ultrasonic washing apparatus comprising a cleaning tank, an ultrasonic multi-frequency oscillator, and the ultrasonic oscillating device is also provided.

Abstract: An ultrasonic transmit-receive probe is disclosed which is capable of effectively protecting an internal structure of the probe against leaked steam so as to ensure stable and positive operation of the probe over a long period of time. The probe includes an enclosing tube arranged in a probe housing. The enclosing tube is sealedly connected at one end thereof to an oscillator housing receiving an oscillator therein to communicate therewith and sealedly fitted at the other end thereof on a plug received in the other end of the probe housing so as to outwardly project therefrom, thereby sealedly protecting the oscillator and plug against the atmosphere in the probe housing.