| 摘要 |
Small, mobile particles in a fluid are optically detected by an apparatus having spaced-apart reflectors (20, 24; 20', 24'; 61, 65) bordering and defining an optical cavity (77; 56) into which a light beam (16; 54) is introduced. The reflectors (20, 24; 20', 24'; 61, 65) are arranged along axes (21, 25; 60, 64) which are slightly misaligned such that the light beam (16; 54) is introduced at a low angle, barely over the edge of one of the reflectors, and is repeatedly reflected between the two reflectors, overlapping itself many times in a view volume (26; 26'; 58) located within the optical cavity (17; 56), thereby increasing the intensity of detected particles. A fluid flow is introduced into the view volume (26; 26'; 58), and the light scattered by particles as they pass through the intensely illuminated view volume is received by a detector (30; 70) which observes the view volume (26; 26'; 58). The detector (30; 70) produces a signal which is indicative of characteristics such as the number or size of particles.
|
