Patent ID: 11402250

Abstract:
The liquid level meter according to the present invention includes a resistive temperature detector, a temperature measuring body located above it, a temperature detecting unit detecting temperatures of the resistive temperature detector and the temperature measuring body, a current controlling unit determining a current value to be flowed through the resistive temperature detector so that the resistive temperature detector and the temperature measuring body become a predetermined temperature difference, a power supply unit supplying the current of the determined current value to the resistive temperature detector, and a liquid level detecting unit detecting a position of a liquid level. The liquid level detecting unit detects the change in the relative position of the liquid level relative to the resistive temperature detector by determining whether a change width of the current value flowing through the resistive temperature detector during a predetermined period of time is positive or negative, and whether the change width is not less than a predetermined value. As a result, the position of the liquid level can be accurately detected without being affected by the variation in the characteristics of the resistive temperature detector.