US4280441A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Temperature indicator
Assignee: PY MAH Corp
•
Filing: 1979-07-06
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Granted: 1981-07-28
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Expires: 1999-07-06
Abstract
Abstract A temperature indicator including a backing strip with an embossed well stamped therein is provided. The well contains a matrix carrier which is impregnated with a thermally responsive fusible chemical. The bottom of the well is painted a bright color. The impregnated matrix is placed over and substantially covers the colored bottom of the well. The top of the well is covered by a transparent film. At a temperature below a predetermined level, the colored bottom of the well is substantially invisible due to the impregnated matrix being opaque, and at temperatures above such predetermined level, the colored bottom of the well is clearly visible due to the transparency of the impregnated matrix upon melting of the chemical.
Inventors
- 👤 Gerald W. McNeely
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:46
CPC Classifications
G; G01; G01K; G01K11/00; G01K11/06; G01K11/12; G01K11/18; G01K3/00; Y; Y10; Y10S; Y10S252/00; Y10S252/962
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
133 words
A reversible steam trap temperature indicator, comprising: (a) a substrate having an embossed well therein; (b) a substantially transparent cover over said well, the bottom of said well being a detectable color; (c) a porous or fibrous carrier received in said well, said carrier voids impregnated with a chemical which is solid below a predetermined temperature and liquid above said predetermined temperature, said carrier adapted to refract light to maintain an opaque cover over the painted bottom of said indicator at least when said chemical is solid; (d) a substantial amount of said chemical remaining in said carrier in both liquid and solid phases, and the color of the bottom of said well being visible when said chemical is in its liquid phase and substantially invisible when it is in its solid phase.
Claim 2
Dependent Claim
133 words
A reversible steam trap temperature indicator, comprising: (a) a substrate having an embossed well therein; (b) a substantially transparent cover over said well, the bottom of said well being a detectable color; (c) a porous or fibrous carrier received in said well, said carrier voids impregnated with a chemical which is solid below a predetermined temperature and liquid above said predetermined temperature, said carrier adapted to refract light to maintain an opaque cover over the painted bottom of said indicator at least when said chemical is solid; (d) a substantial amount of said chemical remaining in said carrier in both liquid and solid phases, and the color of the bottom of said well being visible when said chemical is in its liquid phase and substantially invisible when it is in its solid phase.
Claim 3
Dependent Claim
14 words
The device as set forth in claim 1 wherein the chemical is a hydrocarbon.
Claim 4
Dependent Claim
20 words
The device as set forth in claim 1 wherein said chemical changes from opaque to transparent at said predetermined temperature.
Claim 5
Dependent Claim
26 words
The device as set forth in claim 1, wherein the combination of the carrier and the chemical caused the visibility and invisibility of said colored bottom.
Claim 6
Dependent Claim
30 words
The device as set forth in claim 1 wherein said carrier is optically opaque when said chemical is solid and optically smooth and thus transparent when said chemical is liquid.
Claim 7
Dependent Claim
20 words
The indicator set forth in claim 2 wherein said hydrocarbon is of the general formula C n H 2n+2 .
Claim 8
Dependent Claim
13 words
The device as set forth in claim 1 wherein said chemical is α,α-dichloro-p-xylene.
Claim 9
Dependent Claim
27 words
The indicator as set forth in claim 1, wherein said carrier contains pores of such dimension so as to hold said chemical therein during its liquid phase.
Claim 10
Dependent Claim
131 words
A temperature indicator, comprising: (a) a substrate having an embossed well therein; (b) a substantially transparent cover over said well, the bottom of said well being a detectable color; (c) a carrier received in said well, said carrier impregnated with a chemical which is solid below a predetermined temperature and liquid above said predetermined temperature, wherein said carrier is a matrix containing pores of such dimension so as to hold said chemical therein during its liquid phase, and wherein said carrier matrix is a TFE disc; and (d) a substantial amount of said chemical remaining in said carrier in both liquid and solid phases, and the color of the bottom of said well being visible when said chemical is in its liquid phase and substantially invisible when in its solid phase.
Claim 11
Dependent Claim
131 words
A temperature indicator, comprising: (a) a substrate having an embossed well therein; (b) a substantially transparent cover over said well, the bottom of said well being a detectable color; (c) a carrier received in said well, said carrier impregnated with a chemical which is solid below a predetermined temperature and liquid above said predetermined temperature, wherein said carrier is a matrix containing pores of such dimension so as to hold said chemical therein during its liquid phase, and wherein said carrier matrix is a TFE disc; and (d) a substantial amount of said chemical remaining in said carrier in both liquid and solid phases, and the color of the bottom of said well being visible when said chemical is in its liquid phase and substantially invisible when in its solid phase.
Claim 12
Dependent Claim
16 words
The device as set forth in claim 1, wherein said carrier is a glass filter paper.
Claim 13
Dependent Claim
14 words
The device as set forth in claim 1, wherein said carrier is non-woven polyester.
Claim 14
Dependent Claim
16 words
The device as set forth in claim 1, wherein the indicator is a steam trap monitor.
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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) | 1984-07-27 | 1985-01-26 | 1985-07-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-07-27 | 1989-01-26 | 1989-07-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-07-27 | 1993-01-26 | 1993-07-28 | $7700.00 | Window Closed / Lapsed |