| 摘要 |
PROBLEM TO BE SOLVED: To provide an air filter clogging detecting method capable of directly detecting the clogging state surely with an inexpensive sensor. SOLUTION: A wind speed sensor 6 provided in a front chamber 1a of an air sucking part 1 is formed out of a heating wire which causes a temperature drop due to contact with an air flow X to cause a resistance change, and the sensor is adapted to take the resistance change as the wind speed change and convert the same into the level change of an electric signal. The level change of the electric signal of the wind speed sensor 6 is measured from when the power supply of a fan motor 4 is off unitl the wind speed becomes zero, and clogging is determined when the change amount of the wind speed exceeds its threshold. |
