The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 10, 2011
Filed:
Dec. 12, 2005
Stephen John Penney, Chelmsford, GB;
Stephen John Penney, Chelmsford, GB;
Thorn Security Limited, Sunbury-on-Thames, GB;
Abstract
A self-monitoring smoke detector comprising a housing () defining an internal chamber (). An optical transmitter () is mounted within the housing () so as to direct light into the optical chamber (). An optical receiver () is mounted in the housing () and in optical communication with the optical chamber (). The optical transmitter () and the optical receiver () are so positioned that light from the transmitter cannot directly reach the receiver. Monitoring means is provided, comprising first and second light-scattering means (and) positioned respectively in alignment with the transmitter () and the receiver (). The arrangement is such that, in the absence of reflector particles in the optical chamber, light from the transmitter () can reach the receiver () only after scattering at the first light-scattering means () and then after scattering at the second light-scattering means ().