US4859835A
Expired / Lapsed
US
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Electrically resistive tracks
Assignee: EMI Group Ltd
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Filing: 1988-02-24
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Granted: 1989-08-22
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Expires: 2008-02-24
Abstract
Abstract A heating element comprises an electrically resistive track intended to be formed on an electrically insulative substrate. A heating unit comprises a heating element and a temperature sensor on a substrate, the sensor comprising an electrically resistive track. The track consists of a thick film having in the temperature range of from 0° C. to 550° C. a temperature coefficient of resistance in excess of 0.006 per degree C. The thick film includes a metal and a glass in such proportions as to provide a suitable resistivity and a thermal expansion coefficient to match that of an electrically insulative substrate to which the track is to be applied and to permit adhesion of the track to the substrate. The considerable variation of the resistance of the track with temperature provides advantages in both of the aforementioned applications.
Inventors
- 👤 Simon Balderson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 03:14
CPC Classifications
H; H05; H05B; H05B3/00; H05B3/68; H05B3/74; H05B3/748; H05B3/20; H05B3/22; H05B3/26; H05B2203/00; H05B2203/002; H05B2203/013; H05B2203/017; H05B2213/00; H05B2213/07; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082; Y10T29/49085
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
94 words
A heating unit comprising an electrically insulative substrate and a heating element applied to said substrate, the heating element comprising an electrically resistive track, said track consisting of a thick film having in the temperature range of from 0° C. to 550° C. a temperature coefficient of resistance in excess of 0.006 per degree C, said thick film including a metal and a glass in such proportions as to provide a suitable resistivity and a thermal expansion coefficient to match that of said substrate and to permit adhesion of said track to said substrate.
Claim 2
Dependent Claim
94 words
A heating unit comprising an electrically insulative substrate and a heating element applied to said substrate, the heating element comprising an electrically resistive track, said track consisting of a thick film having in the temperature range of from 0° C. to 550° C. a temperature coefficient of resistance in excess of 0.006 per degree C, said thick film including a metal and a glass in such proportions as to provide a suitable resistivity and a thermal expansion coefficient to match that of said substrate and to permit adhesion of said track to said substrate.
Claim 3
Dependent Claim
90 words
A heating unit according to claim 1 wherein said substrate comprises a plate member having on at least one surface a layer of a glass ceramic material, the glass ceramic layer having a percentage porosity no greater than 2.5, the percentage porosity being defined as the porosity at a random cross-sectional plane through the substrate perpendicular to the plate member expressed as the percentage ratio of the cross-sectional area of the pores on the plane to the cross-sectional area of the remainder of the glass ceramic layer on that plane.
Claim 4
Dependent Claim
26 words
A heating unit according to claim 2 wherein said metal comprises one of the group consisting of transition metals and alloys based on a transition metal.
Claim 5
Dependent Claim
96 words
A heating unit comprising an electrically insulative substrate, a heating element and a temperature sensor applied to said substrate; said sensor including an electrically resistive track, said track consisting of a thick film having in the temperature range of from 0° C. to 500° C. a temperature coefficient of resistance in excess of 0.006 per degree C, said thick film including a metal and a glass in such proportions as to provide a suitable resistivity and a thermal expansion coefficient to match that of said substrate and to permit adhesion of said track to said substrate.
Claim 6
Dependent Claim
96 words
A heating unit comprising an electrically insulative substrate, a heating element and a temperature sensor applied to said substrate; said sensor including an electrically resistive track, said track consisting of a thick film having in the temperature range of from 0° C. to 500° C. a temperature coefficient of resistance in excess of 0.006 per degree C, said thick film including a metal and a glass in such proportions as to provide a suitable resistivity and a thermal expansion coefficient to match that of said substrate and to permit adhesion of said track to said substrate.
Claim 7
Dependent Claim
26 words
A heating unit according to claim 4 wherein said metal comprises one of the group consisting of transition metals and alloys based on a transition metal.
Claim 8
Dependent Claim
86 words
A heating unit according to claim 4 wherein said heating element comprises an electrically resistive track, said track consisting of a thick film having in the temperature range of from 0° C. to 500° C. a temperature coefficient of resistance in excess of 0.006 per degree C, said thick film including a metal and a glass in such proportions as to provide a suitable resistivity and a thermal expansion coefficient to match that of said substrate and to permit adhesion of said track to said substrate.
Claim 9
Dependent Claim
90 words
A heating unit according to claim 4 wherein said substrate comprises a plate member having on at least one surface a layer of a glass ceramic material, the glass ceramic layer having a percentage porosity no greater than 2.5, the percentage porosity being defined as the porosity at a random cross-sectional plane through the substrate perpendicular to the plate member expressed as the percentage ratio of the cross-sectional area of the pores on the plane to the cross-sectional area of the remainder of the glass ceramic layer on that plane.
Claim 10
Dependent Claim
33 words
A heating unit according to claim 1 wherein the proportion by weight of metal and glass in the thick film is in the range of from 50% metal/50% glass to 95% metal/5% glass.
Claim 11
Dependent Claim
26 words
A heating unit according to claim 8 wherein said metal comprises one of the group consisting of transition metals and alloys based on a transition metal.
Claim 12
Dependent Claim
26 words
A heating unit according to claim 6 wherein said metal comprises one of the group consisting of transition metals and alloys based on a transition metal.
Claim 13
Dependent Claim
26 words
A heating unit according to claim 7 wherein said metal comprises one of the group consisting of transition metals and alloys based on a transition metal.
Claim 14
Dependent Claim
26 words
A heating unit according to claim 1 wherein said metal comprises one of the group consisting of transition metals and alloys based on a transition metal.
Claim 15
Dependent Claim
19 words
A heating unit according to claim 12, 3, 9, 5, 10 or 22 wherein said transition metal is nickel.
Claim 16
Dependent Claim
21 words
A heating unit according to claim 12 wherein said transition metal is one of the group consisting of colbalt and iron.
Claim 17
Dependent Claim
90 words
A heating unit according to claim 6 wherein said substrate comprises a plate member having on at least one surface a layer of a glass ceramic maerial, the glass ceramic layer having a percentage porosity not greater than 2.5, the percentage porosity being defined as the porosity at a random cross-sectional plane through the substrate perpendicular to the plate member expressed as the percentage ratio of the cross-sectional area of the pores on the plane to the cross-sectional area of the remainder of the glass ceramic layer on that plane.
Claim 18
Dependent Claim
33 words
A heating unit according to claim 2 wherein the proportion by weight of metal and glass in the thick film is in the range of from 50% metal/50% glass to 95% metal/5% glass.
Claim 19
Dependent Claim
33 words
A heating unit according to claim 4 wherein the proportion by weight of metal and glass in the thick film is in the range of from 50% metal/50% glass to 95% metal/5% glass.
Claim 20
Dependent Claim
33 words
A heating unit according to claim 6 wherein the proportion by weight of metal and glass in the thick film is in the range of from 50% metal/50% glass to 95% metal/5% glass.
Claim 21
Dependent Claim
33 words
A heating unit according to claim 7 wherein the proportion by weight of metal and glass in the thick film is in the range of from 50% metal/50% glass to 95% metal/5% glass.
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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) | 1992-08-21 | 1993-02-20 | 1993-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-21 | 1997-02-20 | 1997-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-21 | 2001-02-20 | 2001-08-22 | $7700.00 | Window Closed / Lapsed |