Hazard detector
US7427925B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 5, 2004 |
| Grant date | Sep 23, 2008 |
| Priority date | — |
| Expiry date | Nov 7, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B29/145
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A hazard detector has an electronic circuit with a start-up program for causing emission of a local indicator signal, such as a flashing signal from a LED, if power and ground terminals of the detector are connected with proper orientation, i.e. polarity, to power and ground lines of a power supply. Through this means, a person installing the hazard detector can tell immediately after connection if the detector has been connected with proper orientation, and avoids the need for introducing a hazard such as heat or smoke to test the operation of the detector. A variation uses a more sophisticated program that disables, during a test mode, complex filtering algorithms that are used by detectors to block false alarm signals; if such filtering is not disabled, impedes normal testing of the detectors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.