| 摘要 |
PURPOSE:To indicate the time to exchange filters with high reliability. CONSTITUTION:The foulness of the air sucked by a fan 1 is measured by a foulness sensor 5. The contamination degree of an electrostatic filter 4 is calculated by an arithmetic part 6 from the foulness and the speed and operating time of the fan. The contamination degree is further converted by the arithmetic part 6 to its ratio to the contamination degree equivalent to the effective working time of the filter 4, and the converted value is indicated on an indicating part 7. |
