John A Mclin

US Patent:

51646048, Nov 17, 1992

Filed:

May 1, 1991

Appl. No.:

7/694188

Inventors:

Harvey V. Blair - Tucson AZ
John McLin - Tucson AZ
Joseph F. Halik - Tucson AZ
William J. Coates - Oro Valley AZ

Assignee:

Allied-Signal Inc. - Morris Township, Morris County NJ

International Classification:

G01N 1506

US Classification:

250574

Abstract:

Detection apparatus employs a plurality of conduits, a plurality of photosensors, and a laser in a multi-port forward-scattering geometry to detect particles for each of a plurality of spatial sections (S. sub. 1,. . . S. sub. n) of an enclosure. The photosensors are provided in two sets arranged at two different scattering angles to discriminate smoke from other particulate matter in sample flows which flow along the conduits and intersect the laser beam. The sample flows are discharged into a plenum and removed from the plenum via a single manifold. The laser can be backed up by an auxiliary laser.