| 摘要 |
1,087,609. Fire detectors. YISSUM RESEARCH DEVELOPMENT CO. Dec. 17, 1965 [Dec. 27, 1964], No. 53699/65. Heading G1N. [Also in Divisions G4 and H3] Smoke and combustion products from a fire, carrying a net electrical charge, are detected by a device comprising an electrical conductor 12, Fig. 1, on whose surface a charge is induced due to the charged smoke &c. The flow of current in a circuit, connected to the conductor, resulting from the induced charge, is amplified and used to energize an alarm and/or automatic fire extinguishing apparatus. The metal conductor, preferably of mesh or perforated sheet may be of any shape, e. g. cylindrical, flat box-shaped or a flat sheet, and is supported by an insulator 13, e. g. of P. T. F. E. An earthed conducting shield 11, of one or more layers of wire mesh or perforated sheet metal, surrounds the conductor 12 and screens it from external fields or charges. The output from the device when smoke is present is fed to a charge sensitive amplifier 15, which energizes a relay 16, having one or more pairs of electrical contacts 17, to operate an alarm 18 and/or fire extinguishing apparatus 19. |
