| 摘要 |
PURPOSE:To stop oscillating the supersonic wave automatically in accordance with an output signal of a detector when a level of liquid is descended to a predetermined level by a method wherein the liquid level detector is provided on the supersonic wave generating device proper. CONSTITUTION:This device is consisting of a casing 2, a supersonic wave oscillator element 3, the liquid level detector and a driving unit 6, into which electronic circuits for thermistors 5-1, 5-2, for example, a high frequency wave generating device for driving the supersonic wave oscillator 1, a control device and the like and a buzzer are incorporated. The liquid level detectors 5-1, 5-2 are attached to the oscillator 1 at the predetermined positions. The thermistors 5-1, 5-2 are provided at positions a1, a2 on the casing 2, for example. In this case, when the working liquid level is descended to a position A and thermistor 5-1 is exposed into air, it is detected and the oscillation of the oscillator 3 is stopped immediately while the buzzer alarms is simultaneously. |
