
US Patent No: 5,444,434
Number of patents in Portfolio can not be more than 2000
Extended life smoke detector
Stats
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Aug 22, 1995
Issued date -
Jun 15, 1992
filing date -
07/899,622
serial no -
In Force
status
Importance
Abstract
The present invention is an improvement in battery powered smoke detectors. A smoke detector is powered by a series connection of two Li/SOCl.sub.2 cells having a capacity of about 2 amp hours. The smoke detector draws a quiescent current of about 7 .mu.A. A low voltage alarm activates when the battery voltage falls below about 6.0 volts upon the periodic application of about a 250 .mu.A to about a 1 mA battery test pulse. The cells are soldered directly into the smoke detector PC board and the smoke detector is placed in an unopenable case to deter battery removal. Smoke detector life expectancy including the battery is 15 years. This invention was made with Government support under grant number SOH (AHR-B) 1 R43 CE00014-01 awarded by the Centers for Disease Control (CDC), Center for Environmental Health and Injury Control (CEHIC), Division of Injury Control. The Government has certain rights in this invention.
First Claim
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International Classification(s)
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Cited Art
| Patent Info | (Count) | # Cites | Year |
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| 4,231,026 Battery discharge level detection circuit | 19 | 1978 | |
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| 5,115,223 Personnel location monitoring system and method | 111 | 1990 | |