Patent US3872355A successfully refreshed from Google Patents.
US3872355A
Expired / Lapsed
US
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Fire detection and projection circuit and device
Assignee: General Electric Co
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Filing: 1973-09-18
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Granted: 1975-03-18
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Expires: 1993-09-18
Abstract
Abstract An early warning fire detection system utilizes a ground fault protected circuit fed through a conventional ground fault circuit interrupter (GFCI) as a vehicle for detecting elevated temperature conditions indicating a fire or incipient fire. Thermal detectors located at strategically-located convenience outlets powered by a ground fault protected circuit or circuits individually operate in response to a predetermined high temperature condition to produce a controlled ground fault, either on the line or the neutral side of the associated circuit, thereby precipitating circuit interrupting operation of the GFCI unit. An alarm associated with the protected circuits is activated in response to the circuit interrupting operation of any of the GFCI units.
Inventors
- 👤 Keith William Klein
- 👤 Norman Thomas Swetnam
- 👤 Robert Allen Cahill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 11:32
CPC Classifications
G; G08; G08B; G08B17/00; G08B17/06; H; H02; H02H; H02H3/00; H02H3/26; H02H3/32; H02H3/33; H02H3/334; H02H5/00; H02H5/04; H02H5/047
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
192 words
An abnormal condition detecTion system using conventional building electrical power distribution circuits which include a line conductor, a neutral conductor and a continuous, conductive ground circuit extending from a load center to various distributed load outlets, wherein the neutral conductor is connected to the ground circuit at a location in the vicinity of the load center, said system comprising, in combination: A. means associated with the line and neutral conductors at a location intermediate the location of neutral conductor ground circuit connection and the load outlets for sensing a ground fault on either conductor; B. an abnormal condition responsive detector located in the vicinity of one of the load outlets and electrically connected between the neutral conductor and the ground circuit, 1. said detector exhibiting a normally high electrical impedance until the condition to which said detector is sensitive reaches a predetermined degree of abnormality, whereupon said detector exhibits a low impedance sufficient to simulate a ground fault on the neutral conductor of sufficient magnitude to produce a response by said sensing means; and C. means responsive to said response of said sensing means for manifesting the existence of the abnormal condition.
Claim 2
Dependent Claim
192 words
An abnormal condition detecTion system using conventional building electrical power distribution circuits which include a line conductor, a neutral conductor and a continuous, conductive ground circuit extending from a load center to various distributed load outlets, wherein the neutral conductor is connected to the ground circuit at a location in the vicinity of the load center, said system comprising, in combination: A. means associated with the line and neutral conductors at a location intermediate the location of neutral conductor ground circuit connection and the load outlets for sensing a ground fault on either conductor; B. an abnormal condition responsive detector located in the vicinity of one of the load outlets and electrically connected between the neutral conductor and the ground circuit, 1. said detector exhibiting a normally high electrical impedance until the condition to which said detector is sensitive reaches a predetermined degree of abnormality, whereupon said detector exhibits a low impedance sufficient to simulate a ground fault on the neutral conductor of sufficient magnitude to produce a response by said sensing means; and C. means responsive to said response of said sensing means for manifesting the existence of the abnormal condition.
Claim 3
Dependent Claim
17 words
The system defined in claim 1, wherein said detector is located in a load outlet receptacle enclosure.
Claim 4
Dependent Claim
99 words
For use in a power distribution circuit protected by a ground fault circuit interrupter unit, an abnormal condition responsive detector adapted for location at a condition monitoring site and for electrical connection between the neutral side of the distribution circuit and ground, said detector having a normally high impedance until the condition to which the detector is sensitive reaches a predetermined degree of abnormality, whereupon said detector exhibits a low impedance sufficient to simulate a ground fault on the neutral side of the distribution circuit of sufficient magnitude to produce a response by the ground fault circuit interrupter unit.
Claim 5
Dependent Claim
99 words
For use in a power distribution circuit protected by a ground fault circuit interrupter unit, an abnormal condition responsive detector adapted for location at a condition monitoring site and for electrical connection between the neutral side of the distribution circuit and ground, said detector having a normally high impedance until the condition to which the detector is sensitive reaches a predetermined degree of abnormality, whereupon said detector exhibits a low impedance sufficient to simulate a ground fault on the neutral side of the distribution circuit of sufficient magnitude to produce a response by the ground fault circuit interrupter unit.
Claim 6
Dependent Claim
55 words
The invention defined in claim 3 wherein said detector is incorporated in an adapter and electrically connected between two conductive prongs carried by said adapter, whereupon plugging said adapter into an outlet socket serviced by the distribution circuit, said detector is electrically connected, via said prongs, between the neutral side of the circuit and ground.
Claim 7
Dependent Claim
33 words
The invention defined in claim 3, wherein said detector is incorporated in a plug receptacle and electrically connected between contacts thereof adapted for connection to the neutral side of the circuit and ground.
Claim 8
Dependent Claim
151 words
For use in a power distribution circuit for distributing electrical power from a load center to a plurality of load outlets, wherein the distribution circuit is equipped with means for sensing a ground fault condition existing on the neutral side thereof, the combination of an abnormal condition responsive detector adapted for electrical connection between the neutral side of the distribution circuit and ground at a location proximate one of the load outlets serviced thereby, said detector exhibiting a normally high electrical impedance until the condition to which said detector is sensitive reaches a predetermined degree of abnormality, whereupon said detector exhibits a low impedance sufficient to simulate a ground fault on the neutral side of the circuit of sufficient magnitude to produce a response by said sensing means; and alarm means adapted for actuation in response to the response of said sensing means to manifest the existence of the abnormal condition.
Claim 9
Dependent Claim
151 words
For use in a power distribution circuit for distributing electrical power from a load center to a plurality of load outlets, wherein the distribution circuit is equipped with means for sensing a ground fault condition existing on the neutral side thereof, the combination of an abnormal condition responsive detector adapted for electrical connection between the neutral side of the distribution circuit and ground at a location proximate one of the load outlets serviced thereby, said detector exhibiting a normally high electrical impedance until the condition to which said detector is sensitive reaches a predetermined degree of abnormality, whereupon said detector exhibits a low impedance sufficient to simulate a ground fault on the neutral side of the circuit of sufficient magnitude to produce a response by said sensing means; and alarm means adapted for actuation in response to the response of said sensing means to manifest the existence of the abnormal condition.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-17 | 1978-09-16 | 1979-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-17 | 1982-09-16 | 1983-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-17 | 1986-09-16 | 1987-03-18 | $7700.00 | Window Closed / Lapsed |