US4146957A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thick film resistance thermometer
Assignee: Engelhard Minerals and Chemicals Corp
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Filing: 1977-01-17
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Granted: 1979-04-03
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Expires: 1997-01-17
Abstract
Abstract A folded, highly pure platinum, thick film, path on a ceramic cylindrical substrate provides a high TCR of about 3850 ppm/ DEG C. The path is applied by screen printing a thick film paste onto a substrate and then firing the paste at a time and temperature sufficient to bond the path to the substrate and to produce a TCR of at least about 3850 ppm/ DEG C. The paste is comprised of about 20% by weight of an organic carrier into which 80% by weight of particles have been mixed. The particles are 96% by weight platinum particles of less than about ten microns size and 4% by weight of a contaminant-free vitreous glass frit of less than ten microns size.
Inventors
- 👤 Donald A. Toenshoff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:36
CPC Classifications
G; G01; G01K; G01K7/00; G01K7/16; G01K7/18; G01K7/183; H; H01; H01C; H01C17/00; H01C17/06; H01C17/065; H01C17/06506; H01C17/06513; H01C17/06526; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082; Y10T29/49085; Y10T29/49099
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
91 words
A method of fabricating a stable thick film having a high temperature coefficient of resistance and a uniform change of resistance with temperature, which comprises (a) preparing a paste comprising substantially non-agglomerated platinum powder having a purity of at least 99.9%, a substantially contaminant-free frit, and an organic vehicle; (b) applying said paste as a continuous thick film strip onto a ceramic substrate; and (c) firing said strip at a temperature of at least 1450° C. to produce a TCR of at least about 3850 ppm/° C. in the fired film.
Claim 2
Independent Claim
91 words
A method of fabricating a stable thick film having a high temperature coefficient of resistance and a uniform change of resistance with temperature, which comprises (a) preparing a paste comprising substantially non-agglomerated platinum powder having a purity of at least 99.9%, a substantially contaminant-free frit, and an organic vehicle; (b) applying said paste as a continuous thick film strip onto a ceramic substrate; and (c) firing said strip at a temperature of at least 1450° C. to produce a TCR of at least about 3850 ppm/° C. in the fired film.
Claim 3
Dependent Claim
42 words
The method of claim 1 wherein said platinum has a tap density above about 5 gm/cc, said paste contains from about 4 to 8% by weight of said frit, and said firing is at a temperature of at least about 1500° C.
Claim 4
Dependent Claim
18 words
The method of claim 1 further comprising the step of: applying a vitreous overglaze to the fired-on strip.
Claim 5
Dependent Claim
28 words
The method of claim 1, wherein said paste contains no more than about 10% by weight of frit based on the total weight of platinum and frit mixture.
Claim 6
Independent Claim
131 words
A method of fabricating a resistance thermometer utilizing a stable thick film resistence path having a high temperature coefficient of resistance and a uniform change of resistance with temperature which comprises (a) preparing a paste comprising substantially non-agglomerated platinum powder having a purity of at least 99.9%, a substantially contaminant-free glass frit, and an organic vehicle, said paste containing from about 4 to 8% by weight of said frit based on the total weight of solids; (b) applying said paste as a continuous thick film strip onto a ceramic substrate; and (c) firing said strip at a temperature of at least 1450° C. to produce a TCR of at least 3850 ppm/° C. in the fired film, and to effect a resistance change of less than 1° C. in equivalent degrees.
Claim 7
Independent Claim
131 words
A method of fabricating a resistance thermometer utilizing a stable thick film resistence path having a high temperature coefficient of resistance and a uniform change of resistance with temperature which comprises (a) preparing a paste comprising substantially non-agglomerated platinum powder having a purity of at least 99.9%, a substantially contaminant-free glass frit, and an organic vehicle, said paste containing from about 4 to 8% by weight of said frit based on the total weight of solids; (b) applying said paste as a continuous thick film strip onto a ceramic substrate; and (c) firing said strip at a temperature of at least 1450° C. to produce a TCR of at least 3850 ppm/° C. in the fired film, and to effect a resistance change of less than 1° C. in equivalent degrees.
Claim 8
Dependent Claim
87 words
The method of claim 5 wherein said step of applying said paste includes: applying said strip as a folded path having legs and end segments, said end segments connecting alternate legs at alternate ends thereof, applying a shorting bar strip spaced from a subset of said end segments, applying a set of extension strips, one each connecting a respective one of said end segments to said shorting bar, and applying an end leg of said path having a width substantially greater than the rest of said legs.
Claim 9
Dependent Claim
49 words
The method of claim 6 further comprising the steps of: opening said extensions one at a time until a path resistance close to and less than a predetermined value is obtained, then trimming the width of said end leg to increase the path resistance up to said predetermined value.
Claim 10
Dependent Claim
16 words
The method of claim 6 wherein said legs are of substantially equal length and electrical resistance.
Claim 11
Dependent Claim
17 words
The method of claim 6 wherein said legs are of a plurality of lengths and electrical resistances.
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) | 1982-04-02 | 1982-10-02 | 1983-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-04-02 | 1986-10-02 | 1987-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-04-02 | 1990-10-02 | 1991-04-03 | $7700.00 | Window Closed / Lapsed |