| 摘要 |
PURPOSE:To facilitate setting of an over-heating preventive device as well as a filter sign by a method wherein only a part of filter net arranged at an air inlet port at the outer surface of a device is made more fine than the remaining part and a temperature sensor for the filter sign is arranged at a part within the device heated by heat. CONSTITUTION:When an indoor heating is performed, dust in indoor air is gradually accumulated in a filter 3 and a part 3a of the filter 3 has a faster clogging of dust as compared with that of the other part 3b, so that the a mount of passing air is rapidly decreased and a part of an air passage guide 7 at which a temperature sensor 12 is fixed is rapidly lifted. The remaining part 3b is gradually clogged with dust later than the above, so that an increase in temperature is delayed at the part of the temperature sensor 11. So, if a sensing level is properly defined, a sufficient difference in time can be attained between time for a display part (a lamp etc.) of a filter sign to operate and operating time for preventing an over-heating operation can be attained and at the same time a sufficient high sensing level for the filter sign can be attained as compared with the room temperature, so that an erroneous operation can be prevented.
|
