Patent US4992638A successfully refreshed from Google Patents.
US4992638A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microwave heating device with microwave distribution modifying means
Assignee: Rio Tinto Alcan International Ltd
•
Filing: 1990-05-04
•
Granted: 1991-02-12
•
Expires: 2010-05-04
Abstract
Abstract A container for heating a substance, e.g. food, in a microwave oven has a bottom transparent to microwave energy. The container is supported on a stand that contains one or more electrically conductive plates (or apertures in an electrically conductive sheet) that generate at least one mode of microwave energy of higher order than the fundamental modes. The stand also serves to support the container above the higher order mode generating plates (or apertures) so that the undersurface of the substance is spaced from them by a uniform predetermined distance. The arrangement has the known features of "bottom heating", i.e. taking advantage of the natural heat flow in the substance, while achieving more uniform heating of the substance by virtue of the higher order mode or modes. As an alternative to or in addition to the generation of higher order modes, the stand may embody elements that modify the microwave pattern in a manner than enhances the coupling of microwave energy into the undersurface of the substance to be heated.
Inventors
- 👤 Bryan C. Hewitt
- 👤 Melville D. Ball
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 19:00
CPC Classifications
H; H05; H05B; H05B6/00; H05B6/64; H05B6/647; H05B6/6491; H05B6/6494; B; B65; B65D; B65D81/00; B65D81/34; B65D81/3446; B65D81/3453; B65D2581/00; B65D2581/34; B65D2581/3437; B65D2581/3439; B65D2581/344; B65D2581/3441; B65D2581/3486; B65D2581/3494; Y; Y10; Y10S; Y10S99/00; Y10S99/14
Claims Analysis
Total Claims: 60
Claim 1
Independent Claim
128 words
A stand for use in a microwave oven having a microwave field pattern for use with a container having at least one portion including a bottom portion transparent to microwave energy, on which bottom portion there is supported an undersurface of a substance to be heated, said stand comprising (a) means for modifying said microwave field pattern to cause at least one mode of microwave energy of higher order than the fundamental modes of such energy to propagate in said substance to provide by means of such higher order mode a significant portion of the heating of said substance, and (b) means for supporting the container spaced above said modifying means so that said undersurface is a distance of at least 3 mm above said field modifying means.
Claim 2
Dependent Claim
128 words
A stand for use in a microwave oven having a microwave field pattern for use with a container having at least one portion including a bottom portion transparent to microwave energy, on which bottom portion there is supported an undersurface of a substance to be heated, said stand comprising (a) means for modifying said microwave field pattern to cause at least one mode of microwave energy of higher order than the fundamental modes of such energy to propagate in said substance to provide by means of such higher order mode a significant portion of the heating of said substance, and (b) means for supporting the container spaced above said modifying means so that said undersurface is a distance of at least 3 mm above said field modifying means.
Claim 3
Dependent Claim
35 words
A stand according to claim 1, wherein said modifying means is planar and said supporting means is dimensioned to support a flat bottom of the container lying in a plane parallel to said modifying means.
Claim 4
Dependent Claim
27 words
A stand according to claim 2, wherein said modifying means comprises at least one plate of electrically conductive material lying in a plane parallel to said bottom.
Claim 5
Dependent Claim
18 words
A stand according to claim 3, including means for spacing said electrically conductive material from an oven floor.
Claim 6
Dependent Claim
30 words
A stand according to claim 2, wherein said modifying means comprises an array of a plurality of plates of electrically conducting material lying in a plane parallel to said bottom.
Claim 7
Dependent Claim
30 words
A stand according to claim 2, wherein said modifying means comprises at least one aperture in a sheet of electrically conductive material lying in a plane parallel to said bottom.
Claim 8
Dependent Claim
34 words
A stand according to claim 2, wherein said modifying means comprises an array of a plurality of apertures in a sheet of electrically conductive material lying generally in a plane parallel to said bottom.
Claim 9
Dependent Claim
40 words
A stand according to claim 7, wherein at least one of said apertures is in a portion of said sheet located at a distance from said undersurface different from the distance of the remainder of said sheet from said undersurface.
Claim 10
Dependent Claim
19 words
A stand according to claim 1, wherein said modifying means comprises portions having different electrical thicknesses from one another.
Claim 11
Dependent Claim
16 words
A stand according to claim 9, wherein said portions have different physical thicknesses from one another.
Claim 12
Dependent Claim
16 words
A stand according to claim 9, wherein said portions have different dielectric constants from one another.
Claim 13
Dependent Claim
18 words
A stand according to claim 1, wherein said modifying means comprises portions having different lossinesses from one another.
Claim 14
Dependent Claim
22 words
A stand according to claim 1, wherein the stand includes upwardly extending, conductive outer portions for shielding side walls of the container.
Claim 15
Dependent Claim
19 words
A stand according to claim 1, wherein said predetermined distance is in the range of 3 to 30 mm.
Claim 16
Dependent Claim
26 words
A stand according to claim 14, wherein the space between the modifying means and the container bottom is air and said distance is approximately 15 mm.
Claim 17
Dependent Claim
26 words
A stand according to claim 14, wherein the space between the modifying means and the container bottom is polyethylene and said distance is approximately 10 mm.
Claim 18
Dependent Claim
31 words
A stand according to claim 14, wherein the space between the modifying means and the container bottom is glass and said distance is in the range from 7 to 10 mm.
Claim 19
Dependent Claim
152 words
A stand for use in a microwave oven for use in combination with a container having at least one portion including a bottom portion transparent to microwave energy, on which bottom portion there is supported an undersurface of a substance to be heated, said stand comprising (a) means for enhancing the coupling of microwave energy into the undersurface of said substance, and (b) means for supporting the container spaced above said coupling enhancement means so that said undersurface is a distance of between one-fifteenth and one-sixth of the wavelength of the microwave energy in the medium between the container and the coupling enhancement means above said coupling enhancement means, (c) wherein said coupling enhancement means comprises a substrate of dielectric material with an array of conductive plates covering at least the majority of the surface area of said substrate, the substrate and the plates cooperatively providing a dielectric constant greater than 10.
Claim 20
Dependent Claim
152 words
A stand for use in a microwave oven for use in combination with a container having at least one portion including a bottom portion transparent to microwave energy, on which bottom portion there is supported an undersurface of a substance to be heated, said stand comprising (a) means for enhancing the coupling of microwave energy into the undersurface of said substance, and (b) means for supporting the container spaced above said coupling enhancement means so that said undersurface is a distance of between one-fifteenth and one-sixth of the wavelength of the microwave energy in the medium between the container and the coupling enhancement means above said coupling enhancement means, (c) wherein said coupling enhancement means comprises a substrate of dielectric material with an array of conductive plates covering at least the majority of the surface area of said substrate, the substrate and the plates cooperatively providing a dielectric constant greater than 10.
Claim 21
Dependent Claim
18 words
A stand according to claim 18, wherein said predetermined distance is in the range 8 to 20 mm.
Claim 22
Dependent Claim
130 words
In combination (a) a container for use in a microwave oven having a microwave field pattern, said container having at least one portion including a bottom portion transparent to microwave energy, on which bottom portion there is supported an undersurface of a substance to be heated, and (b) a stand for such container comprising means for modifying said microwave field pattern, to cause at least one mode of microwave energy of higher order than the fundamental modes of said energy to propagate in said substance to provide by means of such higher order mode a significant portion of the heating of said substance, and means for spacing said container bottom above said modifying means so that said undersurface is a distance of at least 3 mm above said modifying means.
Claim 23
Dependent Claim
130 words
In combination (a) a container for use in a microwave oven having a microwave field pattern, said container having at least one portion including a bottom portion transparent to microwave energy, on which bottom portion there is supported an undersurface of a substance to be heated, and (b) a stand for such container comprising means for modifying said microwave field pattern, to cause at least one mode of microwave energy of higher order than the fundamental modes of said energy to propagate in said substance to provide by means of such higher order mode a significant portion of the heating of said substance, and means for spacing said container bottom above said modifying means so that said undersurface is a distance of at least 3 mm above said modifying means.
Claim 24
Dependent Claim
34 words
The combination of claim 20, wherein said modifying means is planar and said supporting means is dimensioned to support a flat bottom of the container lying in a plane parallel to said modifying means.
Claim 25
Dependent Claim
26 words
The combination of claim 21, wherein said modifying means comprises at least one plate of electrically conductive material lying in a plane parallel to said bottom.
Claim 26
Dependent Claim
17 words
The combination of claim 22, including means for spacing said electrically conductive material from an oven floor.
Claim 27
Dependent Claim
29 words
The combination of claim 21, wherein said modifying means comprises an array of a plurality of plates of electrically conducting material lying in a plane parallel to said bottom.
Claim 28
Dependent Claim
29 words
The combination of claim 21, wherein said modifying means comprises at least one aperture in a sheet of electrically conductive material lying in a plane parallel to said bottom.
Claim 29
Dependent Claim
33 words
The combination of claim 21, wherein said modifying means comprises an array of a plurality of apertures in a sheet of electrically conductive material lying generally in a plane parallel to said bottom.
Claim 30
Dependent Claim
39 words
The combination of claim 26, wherein at least one of said apertures is in a portion of said sheet located at a distance from said undersurface different from the distance of the remainder of said sheet from said undersurface.
Claim 31
Dependent Claim
18 words
The combination of claim 20, wherein said modifying means comprises portions having different electrical thicknesses from one another.
Claim 32
Dependent Claim
15 words
The combination of claim 28, wherein said portions have different physical thicknesses from one another.
Claim 33
Dependent Claim
15 words
The combination of claim 28, wherein said portions have different dielectric constants from one another.
Claim 34
Dependent Claim
17 words
The combination of claim 20, wherein said modifying means comprises portions having different lossinesses from one another.
Claim 35
Dependent Claim
29 words
The combination of claim 20, wherein said container has portions reflective of microwave energy, said at least one transparent portion being principally constituted by the bottom of the container.
Claim 36
Dependent Claim
14 words
The combination of claim 32, wherein said container has reflective side walls and lid.
Claim 37
Dependent Claim
21 words
The combination of claim 20, wherein the stand includes upwardly extending, conductive outer portions for shielding side walls of the container.
Claim 38
Dependent Claim
18 words
The combination of claim 20, wherein said pre distance is in the range of 3 to 30 mm.
Claim 39
Dependent Claim
25 words
The combination of claim 35, wherein the space between the modifying means and the container bottom is air and said distance is approximately 15 mm.
Claim 40
Dependent Claim
25 words
The combination of claim 35, wherein the space between the modifying means and the container bottom is polyethylene and said distance is approximately 10 mm.
Claim 41
Dependent Claim
30 words
The combination of claim 35, wherein the space between the modifying means and the container bottom is glass and said distance is in the range from 7 to 10 mm.
Claim 42
Dependent Claim
151 words
In combination (a) a container for use in a microwave oven having at least one portion including a bottom portion transparent to microwave energy, on which bottom portion there is supported an undersurface of a substance to be heated, and (b) a stand for such container comprising means for enhancing the coupling of microwave energy into the undersurface of said substance, and means into spacing said container bottom above said coupling enhancing means so that said undersurface is a distance of between one-fifteenth and one-sixth of the wavelength of the microwave energy into the medium between the container and the coupling enhancement means above said coupling enhancing means, (c) wherein said coupling enhancement means comprises a substrate of dielectric material with an array of conductive plates covering at least the majority of the surface area of said substrate, the substrate and the plates cooperatively providing a dielectric constant greater than 10.
Claim 43
Dependent Claim
151 words
In combination (a) a container for use in a microwave oven having at least one portion including a bottom portion transparent to microwave energy, on which bottom portion there is supported an undersurface of a substance to be heated, and (b) a stand for such container comprising means for enhancing the coupling of microwave energy into the undersurface of said substance, and means into spacing said container bottom above said coupling enhancing means so that said undersurface is a distance of between one-fifteenth and one-sixth of the wavelength of the microwave energy into the medium between the container and the coupling enhancement means above said coupling enhancing means, (c) wherein said coupling enhancement means comprises a substrate of dielectric material with an array of conductive plates covering at least the majority of the surface area of said substrate, the substrate and the plates cooperatively providing a dielectric constant greater than 10.
Claim 44
Dependent Claim
17 words
The combination of claim 39, wherein said predetermined distance is in the range 8 to 20 mm.
Claim 45
Dependent Claim
131 words
A cooking vessel for use in a microwave oven, comprising a bottom portion and side walls, at least the bottom portion being made of a microwave transparent material, and means for modifying a microwave field pattern to which the vessel is exposed to cause at least one mode of microwave energy of higher order than the fundamental modes of said energy to propagate in a substance supported on an upper surface of said bottom portion to provide by means of such higher order mode a significant portion of the heating of said substance, said means extending across said bottom portion spaced a distance beneath said upper surface of said bottom portion measured in millimeters of at least 3 divided by the square root of the dielectric constant of said bottom portion.
Claim 46
Dependent Claim
131 words
A cooking vessel for use in a microwave oven, comprising a bottom portion and side walls, at least the bottom portion being made of a microwave transparent material, and means for modifying a microwave field pattern to which the vessel is exposed to cause at least one mode of microwave energy of higher order than the fundamental modes of said energy to propagate in a substance supported on an upper surface of said bottom portion to provide by means of such higher order mode a significant portion of the heating of said substance, said means extending across said bottom portion spaced a distance beneath said upper surface of said bottom portion measured in millimeters of at least 3 divided by the square root of the dielectric constant of said bottom portion.
Claim 47
Dependent Claim
16 words
A vessel according to claim 41, wherein said distance is between about 3 and 10 mm.
Claim 48
Dependent Claim
103 words
A cooking vessel for use in a microwave oven, comprising a bottom portion defining a inside bottom surface and side walls of microwave transparent material and a metallised layer extending at least across said bottom portion, said layer having apertures therein to provide means for generating a microwave field pattern having at least one mode of microwave energy of higher order than the fundamental modes of such energy in said vessel, said means being spaced from the inside bottom surface by a distance measured in millimeters of at least 3 divided by the square root of the dielectric constant of said bottom portion.
Claim 49
Dependent Claim
103 words
A cooking vessel for use in a microwave oven, comprising a bottom portion defining a inside bottom surface and side walls of microwave transparent material and a metallised layer extending at least across said bottom portion, said layer having apertures therein to provide means for generating a microwave field pattern having at least one mode of microwave energy of higher order than the fundamental modes of such energy in said vessel, said means being spaced from the inside bottom surface by a distance measured in millimeters of at least 3 divided by the square root of the dielectric constant of said bottom portion.
Claim 50
Dependent Claim
14 words
A vessel according to claim 43, wherein said layer extends up the side walls.
Claim 51
Dependent Claim
130 words
In a method of heating a substance by microwave energy, the steps of (a) confining said substance in a container such that at least some of the energy enters the substance through an undersurface thereof, and (b) at a location beneath said undersurface modifying the microwave field pattern to cause at least one mode of microwave energy of higher order than the fundamental modes of such energy to propagate in said substance to provide by means of such higher order mode a significant portion of the heating of such substance, to improve the uniformity of heating of said substance, said location being spaced a distance beneath said undersurface measured in millimeters of at least 3 divided by the square root of the dielectric constant of the medium in such space.
Claim 52
Dependent Claim
130 words
In a method of heating a substance by microwave energy, the steps of (a) confining said substance in a container such that at least some of the energy enters the substance through an undersurface thereof, and (b) at a location beneath said undersurface modifying the microwave field pattern to cause at least one mode of microwave energy of higher order than the fundamental modes of such energy to propagate in said substance to provide by means of such higher order mode a significant portion of the heating of such substance, to improve the uniformity of heating of said substance, said location being spaced a distance beneath said undersurface measured in millimeters of at least 3 divided by the square root of the dielectric constant of the medium in such space.
Claim 53
Dependent Claim
19 words
The method of claim 45, wherein the majority of all the microwave energy enters the substance through said undersurface.
Claim 54
Dependent Claim
16 words
The method of claim 45, wherein said undersurface is flat and said predetermined distance is uniform.
Claim 55
Dependent Claim
124 words
In a method of heating a substance by microwave energy, the steps of (a) confining said substance in a container such that at least some of the energy enters the substance through an undersurface thereof, and (b) at a location between one-fifteenth and one-sixth of the wavelength of the microwave energy in the medium between said location and said undersurface beneath said undersurface modifying the microwave field pattern to enhance the coupling of microwave energy into said undersurface, (c) wherein said coupling enhancement is achieved by means of a substrate of dielectric material with an array of conductive plates covering at least the majority of the surface areas of said substrate, the substrate and the plates cooperatively providing a dielectric constant greater than 10.
Claim 56
Dependent Claim
124 words
In a method of heating a substance by microwave energy, the steps of (a) confining said substance in a container such that at least some of the energy enters the substance through an undersurface thereof, and (b) at a location between one-fifteenth and one-sixth of the wavelength of the microwave energy in the medium between said location and said undersurface beneath said undersurface modifying the microwave field pattern to enhance the coupling of microwave energy into said undersurface, (c) wherein said coupling enhancement is achieved by means of a substrate of dielectric material with an array of conductive plates covering at least the majority of the surface areas of said substrate, the substrate and the plates cooperatively providing a dielectric constant greater than 10.
Claim 57
Dependent Claim
151 words
A stand for use in a microwave oven having a microwave field pattern for use with a container having at least one portion including a bottom portion transparent to microwave energy, on which bottom portion there is supported an undersurface of a substance to be heated, said stand comprising (a) means for modifying said microwave field pattern to cause at least one mode of microwave energy of higher order than the fundamental modes of such energy to propagate in such substance to provide by means of such higher order mode a significant portion of the heating of said substance, and (b) means for supporting the container spaced above said modifying means with a medium between the container and said modifying means and with said undersurface a distance above said field modifying means measured in millimeters of at least 3 divided by the square root of the dielectric constant of said medium.
Claim 58
Dependent Claim
151 words
A stand for use in a microwave oven having a microwave field pattern for use with a container having at least one portion including a bottom portion transparent to microwave energy, on which bottom portion there is supported an undersurface of a substance to be heated, said stand comprising (a) means for modifying said microwave field pattern to cause at least one mode of microwave energy of higher order than the fundamental modes of such energy to propagate in such substance to provide by means of such higher order mode a significant portion of the heating of said substance, and (b) means for supporting the container spaced above said modifying means with a medium between the container and said modifying means and with said undersurface a distance above said field modifying means measured in millimeters of at least 3 divided by the square root of the dielectric constant of said medium.
Claim 59
Dependent Claim
153 words
In combination (a) a container for use in a microwave oven having a microwave field pattern, said container having at least one portion including a bottom portion transparent to microwave energy, on which bottom portion there is supported an undersurface of a substance to be heated, and (b) a stand for such container comprising means for modifying said microwave field pattern, to cause at least one mode of microwave energy of higher order than the fundamental modes of said energy to propagate in said substance to provide by means of such higher order mode a significant portion of the heating of said substance, and means for spacing said container bottom above said modifying means with a medium between the container and said modifying means and with said undersurface a distance above said modifying means measured in millimeters of at least 3 divided by the square root of the dielectric constant of said medium.
Claim 60
Dependent Claim
153 words
In combination (a) a container for use in a microwave oven having a microwave field pattern, said container having at least one portion including a bottom portion transparent to microwave energy, on which bottom portion there is supported an undersurface of a substance to be heated, and (b) a stand for such container comprising means for modifying said microwave field pattern, to cause at least one mode of microwave energy of higher order than the fundamental modes of said energy to propagate in said substance to provide by means of such higher order mode a significant portion of the heating of said substance, and means for spacing said container bottom above said modifying means with a medium between the container and said modifying means and with said undersurface a distance above said modifying means measured in millimeters of at least 3 divided by the square root of the dielectric constant of said medium.
References Cited (Backward Citations)
US2612596A
Cited
US2600566A
Cited
US3662141A
Cited
US3845266A
Cited
US4019009A
Cited
US4223194A
Cited
US4320274A
Cited
CA1202088A
Cited
US4656325A
Cited
US4683362A
Cited
EP0185488A2
Cited
US4661672A
Cited
CA1239999A
Cited
US4866234A
Cited
EP0246041A2
Cited
EP0271981A2
Cited
US4698472A
Cited
US4888459A
Cited
US4814568A
Cited
US4927991A
Cited
EP0317203A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-02-11 | 1994-08-13 | 1995-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-02-11 | 1998-08-13 | 1999-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-02-11 | 2002-08-13 | 2003-02-12 | $7700.00 | Window Closed / Lapsed |