| 摘要 |
PURPOSE: To prevent the number of revolution of a fan from being frequently changed or the fan from repeating stoppage/operation even if output voltage of a photoelectric dust detector is varied somewhat. CONSTITUTION: A filter 5 for purifying air is installed in a front grill 6. A photoelectric dust detector 8 is incorporated into a side surface of a main body 4. An indicator part 7 consisting of a two-color LED for indicating dust concentration based on output voltage from the photoelectric dust detector 8 is provided to indicate the dust concentration on the indicator part 7, and also when the dust concentration is increased or decreased, the dust concentration indication and the switching time of the number of revolution of a motor 3 are varied by a control part 14 to perform automatic operation. |
