摘要 |
In a light-transmission type smoke detector, a smoke chamber is composed of a disc-like block of a non-conductive material one side of which has a spiral groove and is coated with a conductive bright metal film and a casing mounted on the block, said casing having a plurality of labyrinth structure smoke entrances. An electric circuit system is placed on the other side of the disc-like block and is covered by a shield sheet. The shield sheet and the coating metal film are electrically connected to shield the electric circuit system. |