Apparatus for wide-area fire detection
Number of patents in Portfolio can not be more than 2000
United States of America Patent
Stats
-
Jun 8, 1993
Grant Date -
N/A
app pub date -
Mar 2, 1992
filing date -
Mar 1, 1991
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
In fire detector apparatus for monitoring an extended area from an elevated location, and especially for detecting forest fires, a scanning assembly (1) has azimuthal freedom of movement. A row of adjoining infrared detector element pairs (S, S') is disposed on a common support (7) in the focal plane of a reflector (6). Detector extent or area increases from the optical axis upward, and the detectors are connected with decreasingly sensitive circuitry. As a result, detection areas having different elevations have nearly equal distance range, and detection sensitivity is essentially independent of distance so that a remote forest fire is detected with the same degree of certainty as one close by. For the elimination of false alarms due to diffuse thermal radiation, detector elements are arranged in pairs, side-by-side on the same support (7), and connected in differential circuitry. For the elimination of false alarms due to intense sunlight, light-sensitive solar cells are connected in parallel with the infrared detectors in an inhibition circuit.
First Claim
Other Claims data not available