| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a smoke sensing unit capable of improving outward appearance design and also improving sensing performance. <P>SOLUTION: The smoke sensing unit includes: a housing 1 which has a recessed part 15 which is circular in front view and has a front center part recessed so that a radially inner side is closer to a back side and an inclined part 16 which is inclined so that a radially outer side is closer to the back side; a smoke sensor 4 which is supported by the housing 1 while projecting toward the front side from the recessed part 15; and a front cover 3 which is circular in front view and is supported on the front side of the housing 1 while facing the recessed part 15 at an interval, and covers the smoke sensor 4 from the front side and cooperates with the recessed part 15 to constitute a smoke flow passage 7 guiding smoke to the smoke sensor 4. The front cover 3 includes a collar part 33 which projects radially outward from a border (b) between the recessed part 15 and inclined part 16 over the entire circumference of an outer peripheral part of the front cover 3, and is made apart from the recessed part 15 from the outer peripheral side toward the smoke sensor 4. <P>COPYRIGHT: (C)2013,JPO&INPIT |
