| 摘要 |
729,140. Turbidometers. PYRENE CO., Ltd. March 25, 1953 [April 4, 1952], No. 8744/52. Class 97 (3). [Also in Groups XXXVIII and XL (b)] In a device for detecting the presence of smoke by means of light diffused by the smoke either to the eye or to a photo-electric cell, the centre lines of the illuminating beam and the illuminated field intersect at an angle of less than 70 degrees. As shown, air is drawn from compartments under examination through tubes 12 and into chambers 2, around a central light source 6 and away through exhaust tube 10. The end of each of tubes 12 projects out of the inner wall of the chamber to a point near the light source, a portion of tube being cut away inside the chamber as shown. The light diffused from smoke-laden air in this space is diffused to an observer or a photo-electric cell 16 in the bottom of the apparatus. |
