| 摘要 |
PURPOSE:To indicate automatically the exchanging time of a filter by providing an indicator capable of changing the operating position in accordance with the operating time of a fan. CONSTITUTION:An indicator window 4 is provided on a main body case 1 so that a revolution indicating plate 8 showing the exchange of a filter can be seen. The revolution indicating plate 8 is fixed to a synchronous motor 7 and a pulse is emitted after counting for a specified time by a microcomputer to rotate slightly the synchronous motor and the revolution indicating plate 8 to change the operating position. The desired exchange time of the filter can be easily set by the control of said angle of rotation. By this method, the service time until the present can be stored although an electric power source is not continuously given. |
