Patent FR855408A successfully refreshed from Google Patents.
Patent US4175437A successfully refreshed from Google Patents.
US4175437A
Expired / Lapsed
US
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Fire, temperature or heat detector
Assignee: Individual
•
Filing: 1978-06-19
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Granted: 1979-11-27
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Expires: 1998-06-19
Abstract
Abstract A fire, temperature or heat detection system is disclosed which comprises a cable having at least two conductors separated by insulation whose electrical characteristics vary with temperature, and means connected to the conductors of the cable for detecting variations in the electrical characteristics of the insulation.
Inventors
- 👤 Dennis W. Burt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:12
CPC Classifications
G; G01; G01K; G01K7/00; G01K7/16; G01K7/22; G01K3/00; G01K3/005; G08; G08B; G08B17/00; G08B17/06
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
63 words
A fire, temperature or heat detection system, comprising a cable having at least two conductors separated by an electrically insulating material whose electrical resistance varies as a continuous function of temperature, and signal deriving means connected to the conductors of the cable for deriving an analog signal proportional to the electrical resistance of the insulating material and thus proportional to the cable temperature.
Claim 2
Dependent Claim
63 words
A fire, temperature or heat detection system, comprising a cable having at least two conductors separated by an electrically insulating material whose electrical resistance varies as a continuous function of temperature, and signal deriving means connected to the conductors of the cable for deriving an analog signal proportional to the electrical resistance of the insulating material and thus proportional to the cable temperature.
Claim 3
Dependent Claim
15 words
A detection system as claimed in claim 1, wherein said insulating material is polyvinyl chloride.
Claim 4
Dependent Claim
18 words
A detection system as claimed in claim 1, wherein said insulating material is silicone rubber or ethylene/propylene rubber.
Claim 5
Dependent Claim
17 words
A detection system as claimed in claim 1, wherein said signal deriving means comprises a bridge circuit.
Claim 6
Dependent Claim
17 words
A detection system as claimed in claim 4, wherein said bridge circuit is a Wheatstone bridge circuit.
Claim 7
Dependent Claim
48 words
A detection system as claimed in claim 1, wherein by use of a cable parallel padder resist. and by use of a Wheatstone bridge type circuit with suitable values, the electrical characteristics of the system are modified from a natural linear function to a more desirable sharp curve.
Claim 8
Dependent Claim
31 words
A detection system as claimed in claim 4, wherein the circuit includes means for producing an indication or alarm when the electrical resistance of the insulating material reaches a predetermined value.
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) | 1982-11-26 | 1983-05-28 | 1983-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-11-26 | 1987-05-28 | 1987-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-11-26 | 1991-05-28 | 1991-11-27 | $7700.00 | Window Closed / Lapsed |