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:
Mar. 23, 1982
Filed:
Dec. 19, 1979
Erwin Tresch, Maennedorf, CH;
Cerberus AG, Maennedorf, CH;
Abstract
A smoke detector containing a radiation source operating in a pulsed mode and a scattered radiation receiver connected in a coincidence circuit. This circuit contains a counter which counts both the radiation pulses and the incoming scattered radiation pulses. With undisturbed operation this counter, following each radiation pulse, has an even numbered counter state. The appearance of an uneven numbered counter state is indicative of the presence of spurious pulses and leads to resetting of the counter to null, so that there is prevented attainment of a counter state adequate for tripping an alarm signal. On the other hand, with the presence of a predetermined even numbered counter state there is triggered an alarm. Such smoke detector is almost immune to spurious pulses and does not tend to trigger faulty alarm signals.