WATER-LEAKAGE DETECTING APPARATUS AND METHOD WHICH ARE LITTLE INFLUENCED BY NOISE

摘要

A sensor (1) detects a vibration generated due to water leakage. An integration circuit (13) integrates time intervals for which a signal obtained by absolute-value amplifying an output signal (Ea) From the sensor exceeds a predetermined level (Er), within a predetermined period of time. The integration circuit (13) performs the integration a plurality of times. A detection circuit (15) selects a minimum value of a plurality of integration values obtained by the plurality of measurements as an integration value obtained when the influence of noise is minimum, and compares the minimum value with a preset reference value. When the minimum value exceeds the reference value, the detection circuit (15) determines the presence of water leakage, and when the minimum value is smaller than the reference value, determines the absence of water leakage. A frequency detection circuit (14) calculates a first peak value of an output signal (Ea) from the sensor (1) within the predetermined period of time. A distance from a mounting position of the sensor (1) to a water leakage position is calculated based on the first peak frequency obtained when the minimum value of the plurality of integration values is obtained.