FILTER MONITORING SYSTEM USING A THERMISTOR
    1.
    发明公开
    FILTER MONITORING SYSTEM USING A THERMISTOR 审中-公开
    过滤器监控系统中使用热敏电阻器

    公开(公告)号:EP1161752A1

    公开(公告)日:2001-12-12

    申请号:EP01942461.3

    申请日:2001-01-12

    IPC分类号: G08B21/00 B01D46/42 B01D39/00

    摘要: A system for monitoring a percentage of filter life remaining of a filter assembly of filter-fan devices. The system uses a single thermistor that is operated in two separate modes for monitoring the filter assembly. The thermistor is positioned in the airflow of the filter-fan adjacent to the air outlet. A first current is applied to the thermistor for determining the temperature of the airflow from a first thermistor voltage. The first thermistor voltage is responsive to the first current applied to the thermistor. A second current that is greater than the first current is applied to the heat the thermistor. The temperature of the thermistor is determined from a second thermistor voltage which is responsive to the second current applied to the thermistor. The percentage of filter life remaining of the filter assembly is determined from the temperature of the airflow and the second thermistor voltage.