Photoelectric smoke sensor and fire detecting system, and sensitivity testing method therefor
US5497009A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 27, 1994 |
| Grant date | Mar 5, 1996 |
| Priority date | — |
| Expiry date | Oct 27, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B29/145
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A photoelectric sensor of the present invention includes a light emitting device and a light receiving device for detecting scattered light due to smoke, a light emitting confirming device which lights up when a quantity of light received by the light receiving device is greater than or equal to a threshold and a test light emitting device for emitting light to the light receiving device during the test, wherein a blinking of the light emitting confirming device is started at a time of a test start, and a quantity of light received by the light receiving device is increased in steps so that the blinking is stopped when the quantity is greater than or equal to the threshold. Accordingly, the sensitivity test can be performed by visually counting the number of blinkings of the light emitting device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.