| 摘要 |
PURPOSE:To detect immediately the abnormality based on insulation and short- circuit, by detecting the conduction state of plural electrode bars different in height of lower ends from one another at intervals of a prescribed short time and detecting the abnormal state on the basis of the state of combinations of conduction signals. CONSTITUTION:Four electrode bars 2, 3, 4, and 5 are provided as detecting ends for the purpose of detecting the water level of a water surface 1 of boiler water or the like, and lengths of lower ends of respective electrode bars are different from one another. Each electrode bar is connected to a signal circuit which issues a signal when its lower end is brought into contact with a liquid but does not issue the signal when it is not brought into contact with the liquid. During the operation of a boiler, signals from electrode bars 2, 3, 4, and 5 are checked at intervals of a prescribed short time, and the abnormality is detected on the basis of the mode of the change of combinations of signals when the state of combinations of signals or the measurement time point is changed. |
