| 摘要 |
PURPOSE:To notify the degree of filter clogging accurately when the temperature difference between the neighborhoods of an air inlet and an air outlet reached a fixed amount. CONSTITUTION:Operation control unit 12 encloses a digital counter which counts reference signals during the operation of a coordinating unit. When the counting exceeds a certain fixed amount, control unit 12 issues a signal to detect the temperature difference between temperature detectors 7 and 8 and sends it to temperature detecting circuit 15. When the number of pulses corresponding to the temperatures in the neighborhoods of air inlet 2 and air outlet 3 exceeds a certain fixed value, display signal 19 is output to notifying circuit 13. Clogging is not very bad when it is below the certain fixed value. When the output exceeds the certain fixed value, display signal 9 is issued, notifying circuit 13 is actuated, the clogging of filter 4. |
