| 摘要 |
PROBLEM TO BE SOLVED: To provide a clogging detector of air filters in heat exchanging units which is hardly influenced by external scattered light and is applicable suitably in dark places.SOLUTION: A clogging detector 42 includes a light source 45 which irradiates infrared rays towards an air filter 40 from a primary side of the air filter 40, a pattern 55 which is prepared on the air filter 40 and can reflect the infrared rays irradiated from the light source 45, an image sensor 46 prepared on the primary side of the air filter 40 and can receive the infrared rays reflected from the pattern 55, a recognition part 49 which recognizes the shapes of the pattern 55 through an output signal of the image sensor 46 and a detecting element 50 which detects clogging of the air filter 40 based on the recognition result of the recognition part 49. |
