Patent US3786777A successfully refreshed from Google Patents.
US3786777A
Expired / Lapsed
US
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Irreversible warm-up indicator
Assignee: ARTECH CORP
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Filing: 1970-12-31
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Granted: 1974-01-22
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Expires: 1990-12-31
Abstract
Abstract An indicator for use with a refrigerated object to indicate visually that the object has rewarmed and to warn of possible spoilage. The indicator includes a transparent package housing a frangible container filled with a liquid that expands on freezing and an indicator material placed in proximity thereto which will undergo a color change when contacted by the liquid. The liquid freezes when refrigerated along with the object and expands fracturing the container which previously prevented communication between the liquid and indicator material. Rewarming of the object causes the liquid to melt and contact the indicator material to record by a change of color in the indicator material the fact that the object has rewarmed, even if subsequently recooled. Resilient pressure means, such as a foam pad, an elastic ring, a helical compression spring, a compressed gas bag, an indenter, resilient tongues formed in the indicator material, or equivalent structure is provided in the package between the container and a wall of the package to assure liquid flow from the container in the event of its incomplete or local fracture.
Inventors
- 👤 R Smith
- 👤 W Zimmerman
- 👤 F Ordway
- 👤 C Taylor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:25
CPC Classifications
G; G01; G01K; G01K11/00; G01K11/06
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
238 words
A device for indicating that a refrigerated object has undergone rewarming, said device comprising a sealed package adapted to be placed in proximity to said object, said package including an upper portion having a substantially rigid dome which does not deform under Its own weight and which exerts a bias on deformation from its normal form, a bottom portion sealed along its edges to said upper portion to form with said upper portion a substantially rigid envelope, at least part of said upper and/or bottom portion being transparent, at least one frangible container within said envelope housing a liquid expansible upon freezing to fracture said container, said liquid having a melting temperature above the refrigeration temperature, the container being disposed between the upper and bottom portions under bias of both portions, an indicator material, which exhibits a substantial color change when placed in contact with said liquid adjacent said container within said envelope in proximity to a transparent area of said envelope, whereby said liquid can be refrigerated with said object and upon freezing expand to fracture said container to enable communication to be established between the interior of said container and the indicator material so that if subsequent thawing of said liquid occurs in response to rewarming of said object the pressure applied by said bottom portion against said uppoer portion will cause said liquid to flow from said fractured container into contact with said indicator material.
Claim 2
Independent Claim
238 words
A device for indicating that a refrigerated object has undergone rewarming, said device comprising a sealed package adapted to be placed in proximity to said object, said package including an upper portion having a substantially rigid dome which does not deform under Its own weight and which exerts a bias on deformation from its normal form, a bottom portion sealed along its edges to said upper portion to form with said upper portion a substantially rigid envelope, at least part of said upper and/or bottom portion being transparent, at least one frangible container within said envelope housing a liquid expansible upon freezing to fracture said container, said liquid having a melting temperature above the refrigeration temperature, the container being disposed between the upper and bottom portions under bias of both portions, an indicator material, which exhibits a substantial color change when placed in contact with said liquid adjacent said container within said envelope in proximity to a transparent area of said envelope, whereby said liquid can be refrigerated with said object and upon freezing expand to fracture said container to enable communication to be established between the interior of said container and the indicator material so that if subsequent thawing of said liquid occurs in response to rewarming of said object the pressure applied by said bottom portion against said uppoer portion will cause said liquid to flow from said fractured container into contact with said indicator material.
Claim 3
Dependent Claim
15 words
A device in accordance with claim 1 wherein said bottom portion includes a resilient member.
Claim 4
Dependent Claim
16 words
A device in accordance with claim 2 wherein said resilient member is compressed elastomer foam pad.
Claim 5
Dependent Claim
18 words
A device in accordance with claim 2 wherein said bottom portion is a ring of thin elastic material.
Claim 6
Dependent Claim
16 words
A device in accordance with claim 2 wherein said bottom portion is a helical compression spring.
Claim 7
Dependent Claim
19 words
A device in accordance with claim 2 wherein said bottom portion is a sealed container holding a captive gas.
Claim 8
Dependent Claim
51 words
A device in accordance with claim 2 wherein said container is formed by deformations formed in the dome of said package and an interior seal between said deformations to form a liquid chamber, and said bottom portion including an indenter having a convex surface exerting a bearing force on said seal.
Claim 9
Dependent Claim
75 words
A device in accordance with claim 1 including more than one frangible container filled with a liquid which expands upon freezing, and the liquids in said containers having different melting points so that they are capable of progressively melting as said frozen object thaws, whereby the amount of color change visible on said indicator material is a direct function of the temperature to which said frozen object has been subjected to cause it to melt.
Claim 10
Dependent Claim
29 words
A device in accordance with claim 8 wherein said bottom portion includes a plurality of resilient tongues cut in said indicator material forming seats for each of said containers.
Claim 11
Dependent Claim
26 words
A device in accordance with claim 2 wherein said bottom portion includes a resilient tongue cut in said indicator material forming a seat for said container.
Claim 12
Dependent Claim
20 words
A device in accordance with claim 1 wherein said bottom portion develops a force insufficient to fracture said frangible container.
Claim 13
Dependent Claim
22 words
A device in accordance with claim 1 wherein said indicator material is a coating on the outer surface of said frangible container.
Claim 14
Dependent Claim
23 words
A device in accordance with claim 1 wherein said expansible liquid is of a composition capable of substantially complete isothermal freezing and remelting.
Claim 15
Dependent Claim
15 words
A device in accordance with claim 1 wherein said expansible liquid is essentially pure water.
Claim 16
Dependent Claim
34 words
A device in accordance with claim 1 wherein said expansible liquid is a eutectic composition consisting of a mixture of 19.7 percent by weight of potassium chloride to 80.3 percent by weight of water.
Claim 17
Dependent Claim
17 words
A device in accordance with claim 1 wherein a crystallization catalyst is added to the expansible liquid.
Claim 18
Dependent Claim
29 words
A device in accordance with claim 14 wherein a crystallization catalyst is added to said pure water, said catalyst comprising 0.1 percent by weight of finely divided silver iodide.
Claim 19
Dependent Claim
17 words
A device in accordance wiTh claim 1 wherein said expansible liquid includes a thickener for viscosity control.
Claim 20
Dependent Claim
21 words
A device in accordance with claim 18 wherein said thickener consists of 3 to 4 percent by weight of sodium carboxymethylcellulose.
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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) | 1977-01-21 | 1977-07-23 | 1978-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-21 | 1981-07-23 | 1982-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-21 | 1985-07-23 | 1986-01-22 | $7700.00 | Window Closed / Lapsed |