| 摘要 |
PURPOSE:To judge the life of an air filter simply and accurately by providing a revolution detection sensor for revolutions of a fan motor varying in response to the change in pressure loss of the air filter, and an air filter life judgement device for judging the life of the air filter by estimating the pressure loss of the air filter based upon an output from the sensor. CONSTITUTION:A fan 2 having a revolution detection mechanism which fan is to supply air to be heat-exchanged to a heat exchanger 1 comprises a revolution detection sensor 29, an air filter life judgement device 2b, a fan 2c, and a fan motor 2d. Into the air filter life judgement device 2b there is inputted a static pressure-air flow characteristic and a revolutions-air flow characteristic. The revolution detection sensor 2a detects revolution of the fan motor 2d varying in response to the change in the pressure loss of the air filter 6. The air filter life judgement device 2b estimates the pressure loss of the air filter 6 based upon an output from the revolution detection sensor 2a to judge the life of the air filter. Thus, the life of the air filter can be judged easily and accurately. |
