Individual smoke detector with stored range of acceptable sensitivity
US5721529A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 1, 1996 |
| Grant date | Feb 24, 1998 |
| Priority date | — |
| Expiry date | Aug 1, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B17/113
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A smoke detector is provided with testing apparatus for determining if its sensitivity is within a predetermined acceptable range. The testing apparatus stores in the detector a range representing acceptable sensitivities. When a test is initiated the resulting test output is compared to the sensitivity range, or its representation, and a warning signal is provided when the output is not acceptable. According to one feature, the stored representations of the acceptable range include a maximum acceptable value and a minimum acceptable value, and the warning signal indicates when the output is above the maximum or below the minimum. According to other features, the output signal is periodic at one frequency when above the maximum and at another frequency when below the minimum. The test is initiated by a magnetic reed switch and the results are immediately apparent. Each smoke detector is calibrated on an individual basis that accounts for its particular electrical response, and the calibration information is retained in the detector wherever it goes after installation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.