| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent scale build up on a heated portion by a scale preventing device using ultrasonic vibration by transmitting the ultrasonic vibration to the heated portion without thermally damaging the ultrasonic vibration means. Ž<P>SOLUTION: A liquid tank 1 for storing volatile internal liquid 3 is provided between the heated portion 2 and the ultrasonic vibration means 5. When the volatile internal liquid 3 is heated over the boiling point thereof by the heated portion 2, the increased vapor pressure of the volatile internal liquid 3 in the liquid tank 1 pushes the internal liquid 3 out of the liquid tank 1 to transfer the internal liquid to a reservoir 7 communicating with the liquid tank 1 for temporarily storing the internal liquid therein in order to prevent the heating of the ultrasonic vibration means 5 via the volatile internal liquid 3. When the heated portion 2 is cooled down below the prescribed temperature, the internal liquid 3 in the reservoir 7 is allowed to return to the liquid tank 1 so that the ultrasonic vibration is again transmitted via the internal liquid 3 to vibrate the heated portion 2. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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