Patent · US Expired

Composite fire sensor

US4640628A · kind A · utility

22Cited by
11References
6Claims
0Family size

Inventors

Key dates

Filing dateJul 11, 1985
Grant dateFeb 3, 1987
Priority date
Expiry dateJul 11, 2005

Classification

  • Technology area (CPC G)Physics
  • CPC primaryG08B17/00
  • WIPO fieldControl
  • WIPO sectorInstruments

Abstract

A composite fire sensor comprising a first sensor element sensitive to a change in incident infrared rays, a second sensor element having a variable electric conductivity according to gas absorption/desorption, at least one comparator for combining the outputs of the first and second sensor elements, and a delay circuit for delaying the output of at least one of the comparators. Predetermined reference voltages are supplied to the comparators.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.