Ashfall detector and house with ashfall detector

摘要

PURPOSE:To obtain a falling ash detector for detecting the falling ash with high sensitivity in volcanic district. CONSTITUTION:A port 3 for introducing the outer air is opened upward through one side of a hood 2 and a discharge port 5 is opened through the other side thereof. A constricted part 8 having reduced air supply cross-section area is formed between the introduction port 3 and the discharge port 5 and a light emission sensor 11 and a light receiving sensor are disposed at the constricted part 8. When a motor fan 7 is rotated, outer air is introduced through the introduction port 3 into the hood 2 and eventually discharged through the discharge port 5. The density of ash in the air is increased at the constricted part 8 and the ash is detected with high sensitivity by means of the light emission sensor 11 and the light receiving sensor.