US4222046A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Abnormal condition responsive means with periodic high sensitivity
Assignee: Honeywell Inc
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Filing: 1978-07-31
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Granted: 1980-09-09
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Expires: 1998-07-31
Abstract
Abstract An ionizing type smoke detector device has an output voltage which is compared with a reference voltage and upon the output dropping below the reference, a horn is energized. The reference voltage is normally quite low to reduce the number of false alarms and thus the smoke detector is relatively insensitive to smoldering fires which may require a high sensitivity of the smoke detector device. A timer means periodically modifies the reference voltage to a high value for a short period of time to make the smoke detector more responsive to smoldering fires and yet with the higher sensitivity for the short period of time the number of false alarms are kept at a minimum. Additionally a counter circuit is provided for counting the outputs of the smoke detector over three timing periods and if an output exists for three consecutive periods, an output to the horn is provided.
Inventors
- 👤 B. Hubert Pinckaers
- 👤 Stephen A. Haglund
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:16
CPC Classifications
G; G08; G08B; G08B17/00; G08B17/10; G08B17/11; Y; Y10; Y10S; Y10S331/00; Y10S331/03
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
168 words
In a condition responsive device having a high sensitivity for detection of abnormal conditions and having an acceptable tolerance to false alarms, comprising condition responsive means having a first ouput signal upon the presence of a predetermined level of a condition, reference signal means having a reference output signal varying with the desired level of said condition for providing an alarm, comparator means connected to receive said first output signal and said reference output signal for instantaneously comparing said signals and providing an alarm output signal when said first output signal compares with said reference output signal, annunciator means connected to said comparator means for responding to said alarm output signal, and means connected to said reference signal means for changing said reference output signal, said reference output signal having a first normal value whereby said comparator means is responsive to conditions of large magnitudes and false alarms are minimized and having a second short periodic value whereby said comparator means is responsive to conditions of small magnitudes.
Claim 2
Dependent Claim
168 words
In a condition responsive device having a high sensitivity for detection of abnormal conditions and having an acceptable tolerance to false alarms, comprising condition responsive means having a first ouput signal upon the presence of a predetermined level of a condition, reference signal means having a reference output signal varying with the desired level of said condition for providing an alarm, comparator means connected to receive said first output signal and said reference output signal for instantaneously comparing said signals and providing an alarm output signal when said first output signal compares with said reference output signal, annunciator means connected to said comparator means for responding to said alarm output signal, and means connected to said reference signal means for changing said reference output signal, said reference output signal having a first normal value whereby said comparator means is responsive to conditions of large magnitudes and false alarms are minimized and having a second short periodic value whereby said comparator means is responsive to conditions of small magnitudes.
Claim 3
Dependent Claim
74 words
The invention of claim 1 wherein, said condition responsive means is a smoke detector for detecting the presence of smoke in the air of a space, and said reference output signal having said second value for several millisecond periods each several minutes to make the smoke detector responsive only to large levels of smoke most of the time and responsive to small levels of smoke indicative of smoldering fire conditions during said millisecond periods.
Claim 4
Dependent Claim
28 words
The invention of claim 2 wherein said means connected to said reference signal means is a timer means to periodically change the value of said refernce output signal.
Claim 5
Dependent Claim
27 words
The invention of claim 3 wherein said timer means provides for a reference output signal to have said annunciator respond periodically to a small level of smoke.
Claim 6
Dependent Claim
25 words
The invention of claim 2 wherein said smoke detector comprises an ionization chamber for providing said first output signal when smoke is in said chamber.
Claim 7
Dependent Claim
42 words
The invention of claim 2 comprising counting circuit member responsive to said alarm output signal to provide for operation of said annunciator means only after three consecutive alarm output signals, having a first time period therebetween, are received by said annunciator means.
Claim 8
Dependent Claim
51 words
The invention of claim 6 wherein said counting circuit means is activated each of said millisecond periods when an alarm output signal exists with means to reset said counting means to zero when an alarm output signal does not exist for a predetermined time period longer than said first time period.
Claim 9
Dependent Claim
127 words
An improvement in a detector alarm device having a condition responsive means and a reference means connected by a comparator means to an annunciator means wherein the sensitivity of the condition responsive means determines the number of false alarms and to reduce the number of false alarms, the sensitivity is maintained at a low level by the output of the reference means, the improvement comprising, timer means, and means connected to said timer means to periodically modify the output of said reference means to change the sensitivity of the responsive means to a high level of sensitivity to respond to low levels of condition but by maintaining the total percentage of time for high level sensitivity small enough to maintain the false alarms to an acceptable level.
Claim 10
Dependent Claim
127 words
An improvement in a detector alarm device having a condition responsive means and a reference means connected by a comparator means to an annunciator means wherein the sensitivity of the condition responsive means determines the number of false alarms and to reduce the number of false alarms, the sensitivity is maintained at a low level by the output of the reference means, the improvement comprising, timer means, and means connected to said timer means to periodically modify the output of said reference means to change the sensitivity of the responsive means to a high level of sensitivity to respond to low levels of condition but by maintaining the total percentage of time for high level sensitivity small enough to maintain the false alarms to an acceptable level.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-09-09 | 1984-03-10 | 1984-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-09-09 | 1988-03-10 | 1988-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-09-09 | 1992-03-10 | 1992-09-09 | $7700.00 | Window Closed / Lapsed |