FOREIGN MATTER DETECTION DEVICE

To provide a foreign matter detection device capable of preventing erroneous detection while suppressing deterioration of detection sensitivity.SOLUTION: Each one of foreign matter detection devices 1 sucks air in a foreign matter detection object space 8 such as a cargo chamber through a vent tube 6 by a suction fan 3, and supplies the air to a detection area inside a detection space forming body for optically detecting foreign matters such as smoke particles in the air. The detection space forming body includes a clean air introduction hole. Outer air is introduced into a detection space through the clean air introduction hole during sucking, foreign matters are restricted from adhering to a wall surface and foreign matter detection means or the like, and adhering foreign matters are removed. After removal of foreign matters for a fixed time ends, air suction is stopped for a predetermined time. A flow of the air is stopped, and then smoke particles or the like being present in the detection space are detected.SELECTED DRAWING: Figure 1 【課題】検出感度の低下を抑制し、誤検出を防止することができる異物検出装置を提供する。【解決手段】異物検出装置１は、吸引ファン３によって、通気管６を介して荷室などの異物検出対象空間８の空気を吸い込んで、空気中の煙粒子などの異物を光学的に検出する検出空間形成体内の検出領域に供給する。検出空間形成体には清浄空気導入孔が設けられ、吸引中は清浄空気導入孔を介して検出空間内に外気が導入され、壁面、異物検出手段などのへ異物の付着を抑制し、付着した異物を除去する。一定時間の異物の除去が終了後、所定の時間空気の吸引を停止し、空気の流れを停止した後、検出空間に存在する煙粒子などの検出を行う。【選択図】図１