| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a smoke detector suitable for mounting on a duct for detection of suspended particles, especially for early detection of smoke created by unexpected pyrolysis or combustion of materials in a fire protection area or a fire zone. <P>SOLUTION: In this smoke detector 10, a first beam and a second beam are alternately radiated to a detection zone 12. This detector, provided with a long service life and reduced in size and weight and manufacturable at a low cost, retains sensitivity to a wide range of particle sizes and also discriminates between different kinds of smoke or dust according to particle size. <P>COPYRIGHT: (C)2008,JPO&INPIT |
