| 摘要 |
1528671 Smoke detector JSN BARKER 21 March 1977 [26 Jan 1976] 02881/76 Heading G1A [Also in Division G4] A smoke detector includes casing 10 defining air chamber 26, which has an electric light bulb socket 20 and a plug 16 supplying the bulb therein on being engaged with a mains socket, and which is above socket 20 and has an opening, as 46, for receiving surrounding air heated by the bulb and electrical means arranged to give a signal if chamber 26 contains smoke. Light from the bulb shines through chimney 48 into chamber 26. If it is scattered by smoke on to photo-cell 54, loudspeaker 32 is caused by the circuit of Fig. 4 (not shown) to sound. A switch for the bulb and a separate light source for smoke detection may be provided. |
