EP0271981A2
Expired / Lapsed
EP
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Microwave container
Assignee: Rio Tinto Alcan International Ltd
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Filing: 1987-10-23
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Granted: —
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Expires: 2007-10-23
Abstract
Abstract A container for holding a body (160) of material such as foodstuff to be heated in a microwave oven, including a dielectric lid (161) and/or other dielectric wall structure with at least two contiguous dielectric wall portions (166,168) of respectively different electrical thickness for co-operatively modifying the microwave electric field patterns that would obtain in the body during such heating if the lid and/or other dielectric wall structure were of uniform electrical thickness or were absent. At least one of the portions, preferably the portion of higher electrical thickness, may be so constituted as to undergo a change in dielectric constant during the microwave heating, thereby to alter the heating distribution in the body as heating proceeds.
Inventors
- 👤 Richard Mackay Keefer
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 18:45
CPC Classifications
B; B65; B65D; B65D81/00; B65D81/34; B65D81/3446; B65D81/3453; B65D2581/00; B65D2581/34; B65D2581/3437; B65D2581/3439; B65D2581/344; B65D2581/3441; B65D2581/3471; B65D2581/3472; B65D2581/3486; B65D2581/3487; B65D2581/3489
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
100 words
A container for holding a body of material to be heated in a microwave oven, said container including a dielectric wall structure comprising at least a first and a second contiguous dielectric wall portions of respectively different electrical thickness for co-operatively modifying the microwave electric field pattern that would obtain in the body during such heating if the wall structure were of uniform dielectric thickness or were absent in such a way as to generate in the container a microwave electric field pattern having at least one higher order mode than a fundamental mode of the container or its contents.
Claim 2
Dependent Claim
100 words
A container for holding a body of material to be heated in a microwave oven, said container including a dielectric wall structure comprising at least a first and a second contiguous dielectric wall portions of respectively different electrical thickness for co-operatively modifying the microwave electric field pattern that would obtain in the body during such heating if the wall structure were of uniform dielectric thickness or were absent in such a way as to generate in the container a microwave electric field pattern having at least one higher order mode than a fundamental mode of the container or its contents.
Claim 3
Dependent Claim
20 words
A container as claimed in claim 1, wherein said first portion has a greater electrical thickness than said first portion.
Claim 4
Dependent Claim
20 words
A container as claimed in claim 1, wherein said second portio has a greater electrical thickness than said first portion.
Claim 5
Dependent Claim
42 words
A container as claimed in any one of claims 1 to 3, wherein that dielectric wall portion having a greater electrical thickness comprises a material having a higher dielectric constant than the material of that dielectric wall portion of lesser electrical thickness.
Claim 6
Dependent Claim
34 words
A container as claimed in any one of claims 1 to 4, wherein that dielectric wall portion having a greater electrical thickness has a greater spatial thickness than said portion of lesser electrical thickness.
Claim 7
Dependent Claim
61 words
A container as claimed in any one of claims 1, 2 or 3 wherein the material of said first dielectric wall portion is the same as the material of said second dielectric wall portion, and is integral therewith, and wherein that wall portion having the greater electrical thickness has a greater spatial thickness than the said portion of lesser electrical thickness.
Claim 8
Dependent Claim
36 words
A container as claimed in any one of the preceding claims, wherein said first and second wall portions of respectively greater and lesser electrical thickness are demarcated by an abrupt discontinuity in dielectric thickness between them.
Claim 9
Dependent Claim
27 words
A container as claimed in any one of claims 1 to 6 wherein the variation of electrical thickness between said first and second wall portions is gradual.
Claim 10
Dependent Claim
38 words
A container as claimed in any one of the preceding claims wherein that dielectric wall portion having a greater electrical thickness comprises a multilayer structure having a total spatial thickness greater than said portion of lesser electrical thickness.
Claim 11
Dependent Claim
71 words
A container as claimed in claim 9 wherein said dielectric wall structure comprises a wall having attached to one surface thereof a block of dielectric material, the arrangement being such that that part of the wall covered by the block constitutes said dielectric wall portion having a greater electrical thickness, while that part of the wall not covered by the block constitutes said dielectric wall portion havig a lesser electrical thickness.
Claim 12
Dependent Claim
38 words
A container as claimed in any one of the preceding claims wherein at least one of said dielectric wall portions is so constituted as to undergo a change in dielectric constant when subjected to irradiation by microwave energy.
Claim 13
Dependent Claim
36 words
A container as claimed in claim 11, wherein the last-mentioned dielectric wall portion is said portion of greater electrical thickness and is of such a nature that it exhibits a decrease in dielectric constant when heated.
Claim 14
Dependent Claim
18 words
A container as claimed in claim 12, wherein said decrease occurs upon attainment of a predetermined elevated temperature.
Claim 15
Dependent Claim
84 words
A container as claimed in any one of the preceding claims, said container comprising an open-topped tray for carrying the material and a lid covering the tray to form a closed cavity, the container being characterised in that at least one surface of the container is formed with said dielectric wall structure which is so dimensioned and positioned with respect to the material when in the container that the higher order mode so generated propagates into the material thereby to locally heat the material.
Claim 16
Independent Claim
109 words
A method of heating a body of microwave-heatable material, said method comprising disposing said body in a container including a dielectric wall structure comprising at least first and second dielectric wall portions of respectively greater and lesser electrical thickness co-operatively configured and arranged to modify the microwave electric field pattern within the body in such a way as to generate in the container a microwave electric field pattern having at least one higher order mode than a fundamental mode of the container or its contents; placing the container, with the body disposed therein, in a microwave oven; and irradiating the container and body with microwave energy in the oven.
Claim 17
Independent Claim
109 words
A method of heating a body of microwave-heatable material, said method comprising disposing said body in a container including a dielectric wall structure comprising at least first and second dielectric wall portions of respectively greater and lesser electrical thickness co-operatively configured and arranged to modify the microwave electric field pattern within the body in such a way as to generate in the container a microwave electric field pattern having at least one higher order mode than a fundamental mode of the container or its contents; placing the container, with the body disposed therein, in a microwave oven; and irradiating the container and body with microwave energy in the oven.
Claim 18
Dependent Claim
47 words
A method as claimed in claim 15, wherein at least one of said dielectric wall portions undergoes a change in dielectric constant during heating, and wherein the irradiating step is continued until after said change occurs, for altering the heat distribution pattern in the body during heating.
References Cited (Backward Citations)
No citation records indexed.
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