EP0161739A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Microwave heating package
Assignee: Rio Tinto Alcan International Ltd
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Filing: 1985-02-12
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Granted: —
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Expires: 2005-02-12
Abstract
Abstract A novel cover (38, 40, 48) arrangement is described for use with foodstuff holding pans (30) to be heated in a microwave oven. The cover is one which in terms of microwave energy, does not transmit reflected energy. Thus, the cover acts in a manner analogous with non-reflecting coatings in optics and permits passage of the microwave radiation into the container holding the foodstuff (18), while substantially preventing escape of microwave radiation reflected from the foodstuff surface and container bottom (32). In this manner the microwave energy is retained and concentrated within the container, resulting in more efficient and uniform heating of the foodstuff. The novel cover is particularly valuable when used with aluminium foil pans, which without the cover of this invention seriously reflect microwave radiation.
Inventors
- 👤 Richard M. Keefer
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 05:04
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; B65D2581/3463; B65D2581/3464; B65D2581/3471; B65D2581/3472; B65D2581/3479; B65D2581/3486; B65D2581/3487
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
223 words
A package containing an article of foodstuff, said foodstuff being capable of being heated in a microwave oven, said package being characterized by a foodstuff holding pan (30), said pan having a bottom (32), side walls (34) and an open top and a non-reflecting energy cover (38) for said pan, said cover (38) being in the form of substantially uniform dielectric materials (40) having dielectric constants greater than 10 and for which the characteristics of reflectance and transmittance are functions of thickness or in the form of a dielectric substrate having metal powder or flakes dispersed therein or thereon and for which the characteristics of reflectance and transmittance are at least equivalent to those obtained from said uniform dielectric materials or in the form of arrays of conductors (48) on or embedded in a dielectric substrate and for which the characteristics of reflectance and transmittance are at least equivalent to those obtained from said uniform dielectric materials, and being spaced from the top surface of the foodstuff (18) a distance of about 0.8 to 2 cm. at a frequency of 2450 MHz., the characteristics of the cover and the spacing thereof from the foodstuff permitting passage of microwave radiation through the cover into the package while interfering with reflected radiation within the package, thereby retaining and concentrating the microwave energy within the package.
Claim 2
Dependent Claim
223 words
A package containing an article of foodstuff, said foodstuff being capable of being heated in a microwave oven, said package being characterized by a foodstuff holding pan (30), said pan having a bottom (32), side walls (34) and an open top and a non-reflecting energy cover (38) for said pan, said cover (38) being in the form of substantially uniform dielectric materials (40) having dielectric constants greater than 10 and for which the characteristics of reflectance and transmittance are functions of thickness or in the form of a dielectric substrate having metal powder or flakes dispersed therein or thereon and for which the characteristics of reflectance and transmittance are at least equivalent to those obtained from said uniform dielectric materials or in the form of arrays of conductors (48) on or embedded in a dielectric substrate and for which the characteristics of reflectance and transmittance are at least equivalent to those obtained from said uniform dielectric materials, and being spaced from the top surface of the foodstuff (18) a distance of about 0.8 to 2 cm. at a frequency of 2450 MHz., the characteristics of the cover and the spacing thereof from the foodstuff permitting passage of microwave radiation through the cover into the package while interfering with reflected radiation within the package, thereby retaining and concentrating the microwave energy within the package.
Claim 3
Dependent Claim
17 words
A package according to claim 1 further characterized by the pan (30) is an aluminum foil pan.
Claim 4
Dependent Claim
50 words
A package according to claim 2 further characterized by said cover (38) is comprised of a dielectric substrate (40) having metal powder or flakes (48) dispersed therein or thereon and for which the characteristics of reflectance and transmittance are at least equivalent to those obtained from said uniform dielectric materials.
Claim 5
Dependent Claim
19 words
A package according to claim 3 further characterized by the dielectric substrate (40) is a low loss dielectric paper.
Claim 6
Dependent Claim
49 words
A package according to claim 2 further characterized by said cover (38) is comprised of said arrays of conductors (48) on or embedded in a dielectric substrate (40) and for which the characteristics of reflectance and transmittance are at least equivalent to those obtained from said uniform dielectric materials.
Claim 7
Dependent Claim
35 words
A package according to claim 5 further characterized by the conductors (48) are metal or metal foil shapes having side dimensions and spacing from each other of less than one wavelength of the microwave energy.
Claim 8
Dependent Claim
38 words
A package according to claim 6 further characterized by the metal foil shapes (48) form islands on or in the dielectric substrate (40), with the foil shapes representing 50 to 80% of the total area of the cover.
Claim 9
Dependent Claim
28 words
A package according to claim 7 further characterized by the dielectric substrate (40) is a cellulosic or plastic resinous sheet or film having a low dielectric loss factor.
Claim 10
Dependent Claim
17 words
A package according to claim 8 further characterized by the foil shapes (48) are aluminum foil shapes.
Claim 11
Dependent Claim
18 words
A package according to claim 9 further characterized by the foil shapes (48) are generally rectangular or square.
Claim 12
Dependent Claim
36 words
A package according to claim 7 further characterized by the distance between the top of the foodstuff (18) and the non-reflecting energy cover (10) is about 1.2 to 1.5 cm. at a frequency of 2450 MHz.
Claim 13
Independent Claim
216 words
A method of heating in a microwave oven, a foodstuff in a foodstuff holding pan (30), the method bieng charactarized by the steps of: placing over the open top of the pan at a distance of about 0.8 to 2 cm. at a frequency of 2450 MHz. above the foodstuff a non-reflecting energy cover (38), said cover being in the form of substantially uniform dielectric materials having dielectric constants greater than 10 and for which the characteristics of reflectance and transmittance are functions of thickness or in the form of a dielectric substrate (40) having metal powder or flakes (48) dispersed therein or thereon and for which the characteristics of reflectance and transmittance are at least equivalent to those obtained from said uniform dielectric materials or in the form of arrays of conductors (48) on or embedded in a dielectric substrate (40) and for which the characteristics of reflectance and transmittance are at least equivalent to those obtained from said uniform dielectric materials, and subjecting said non-reflected energy cover (10) and foodstuff (18) to microwave energy for a period of time sufficient to heat or cook the foodstuff, said cover permitting passage of microwave radiation into the pan while interfering with reflected radiation within the package, thereby retaining and concentrating the microwave energy within the pan.
Claim 14
Independent Claim
216 words
A method of heating in a microwave oven, a foodstuff in a foodstuff holding pan (30), the method bieng charactarized by the steps of: placing over the open top of the pan at a distance of about 0.8 to 2 cm. at a frequency of 2450 MHz. above the foodstuff a non-reflecting energy cover (38), said cover being in the form of substantially uniform dielectric materials having dielectric constants greater than 10 and for which the characteristics of reflectance and transmittance are functions of thickness or in the form of a dielectric substrate (40) having metal powder or flakes (48) dispersed therein or thereon and for which the characteristics of reflectance and transmittance are at least equivalent to those obtained from said uniform dielectric materials or in the form of arrays of conductors (48) on or embedded in a dielectric substrate (40) and for which the characteristics of reflectance and transmittance are at least equivalent to those obtained from said uniform dielectric materials, and subjecting said non-reflected energy cover (10) and foodstuff (18) to microwave energy for a period of time sufficient to heat or cook the foodstuff, said cover permitting passage of microwave radiation into the pan while interfering with reflected radiation within the package, thereby retaining and concentrating the microwave energy within the pan.
Claim 15
Dependent Claim
17 words
A method according to claim 12 further characterized by the pan (30) is an aluminum foil pan.
Claim 16
Dependent Claim
36 words
A method according to claim 12 or 13 further characterized by the microwave energy is applied for a time and intensity sufficient to heat or cook the foodstuff (18) and brown and/or crispen the surface thereof.
Claim 17
Dependent Claim
96 words
A container for use in heating a foodstuff (18) with microwave energy said container being characterized by a foodstuff holding pan, (30) and a top cover (38), said top cover having a shoulder portion (42) and a substantially planar top surface (40), said shoulder portion being dimensioned so as to elevate said top surface about from V15 to V6 of said microwave energy above the surface of said foodstuff, said top surface being comprised of an array dielectric, said array dielectric being comprised of a plurality of metallic islands (48) located on a dielectric substrate (40).
Claim 18
Dependent Claim
96 words
A container for use in heating a foodstuff (18) with microwave energy said container being characterized by a foodstuff holding pan, (30) and a top cover (38), said top cover having a shoulder portion (42) and a substantially planar top surface (40), said shoulder portion being dimensioned so as to elevate said top surface about from V15 to V6 of said microwave energy above the surface of said foodstuff, said top surface being comprised of an array dielectric, said array dielectric being comprised of a plurality of metallic islands (48) located on a dielectric substrate (40).
Claim 19
Dependent Claim
25 words
The container of claim 15, further characterized by said pan has a metallic bottom (32) which acts as a ground plane to said microwave energy.
Claim 20
Dependent Claim
14 words
The container of claim 15, further characterized by said pan (30) is a metal.
Claim 21
Dependent Claim
28 words
The container of claim 15, further characterized by each of said metallic islands (48) is comprised of a metallic film or foil bonded to said dielectric substrate (40).
Claim 22
Dependent Claim
17 words
The container of claim 18, further characterized by said film or foil is approximately 0.001 inches thick.
Claim 23
Dependent Claim
32 words
The container of claim 15, further characterized by the metallic islands (48) have a total surface area which is between 50 and 80 percent of the surface area of the top surface.
Claim 24
Dependent Claim
27 words
The container of claim 15, further characterized by each of said metallic islands (48) is comprised of a metallic film or foil embedded within said dielectric substrate.
Claim 25
Dependent Claim
54 words
The container of claim 17, further characterized by said pan (30) and top cover (38) are generally rectangular with curved corners and wherein said pan has a radially outwardly extending lip (36) and said top cover has a radially extending step (44) connected to said shoulder portion (42) for frictional cooperation with said lip.
Claim 26
Dependent Claim
22 words
The container of claim 22, further characterized by a downwardly and outwardly extending, insulative skirt (46) is attached to said step (44).
Claim 27
Dependent Claim
52 words
The container of claim 17, further characterized by said pan (30) and said top cover (38) are generally circular and wherein said pan has a radially outwardly extending lip (36) and said top cover has a radially extending step (44) connected to said shoulder portion (42) for frictional cooperation with said lip.
Claim 28
Dependent Claim
22 words
The container of claim 24, further characterized by a downwardly and outwardly extending, insulative skirt (46) is attached to said step (44).
Claim 29
Dependent Claim
196 words
A container for use in heating a foodstuff (18) with microwave energy, said container being charactarized by a generally rectangular metallic pan (30) having a substantially flat bottom (32), outer side walls (34) and inner partition walls forming a plurality of compartments (50, 51, 52, 53); said container further including a cooperating top cover (38), said top cover having a shoulder portion which is comprised of an exterior shoulder portion (42) and interior partition shoulders, generally congruent with said inner partition walls to thereby form a plurality of top surfaces (40), one over each of said plurality of compartments in a one-to-one correspondence, said exterior shoulder portion and said inner partition shoulders being dimensioned so as to elevate said plurality of top surfaces above said foodstuff from between X/15 and X/6 of said microwave energy, said top cover comprising a dielectric material (40) at each of said plurality of top surfaces, wherein selected top surfaces further include arrays of metallic islands (48) so that said selected top surfaces form array dielectrics having relatively high dielectric constants, and wherein other selected top surfaces include a metallic film or foil (54) on substantially the entire surface area thereof.
Claim 30
Dependent Claim
196 words
A container for use in heating a foodstuff (18) with microwave energy, said container being charactarized by a generally rectangular metallic pan (30) having a substantially flat bottom (32), outer side walls (34) and inner partition walls forming a plurality of compartments (50, 51, 52, 53); said container further including a cooperating top cover (38), said top cover having a shoulder portion which is comprised of an exterior shoulder portion (42) and interior partition shoulders, generally congruent with said inner partition walls to thereby form a plurality of top surfaces (40), one over each of said plurality of compartments in a one-to-one correspondence, said exterior shoulder portion and said inner partition shoulders being dimensioned so as to elevate said plurality of top surfaces above said foodstuff from between X/15 and X/6 of said microwave energy, said top cover comprising a dielectric material (40) at each of said plurality of top surfaces, wherein selected top surfaces further include arrays of metallic islands (48) so that said selected top surfaces form array dielectrics having relatively high dielectric constants, and wherein other selected top surfaces include a metallic film or foil (54) on substantially the entire surface area thereof.
Claim 31
Dependent Claim
85 words
A top (38) for use with a pan in the microwave cooking of a foodstuff (18), said top being charactarized by a shoulder portion (42) and a top surface portion (40), said shoulder portion being dimensioned to control the elevation of said top surface portion above said foodstuff to from λ/15 to V6 of said microwave energy, said top surface portion being comprised of a dielectric substrate (40) and a plurality of metallic islands (48) forming an array dielectric having a relatively high dielectric constant.
Claim 32
Dependent Claim
85 words
A top (38) for use with a pan in the microwave cooking of a foodstuff (18), said top being charactarized by a shoulder portion (42) and a top surface portion (40), said shoulder portion being dimensioned to control the elevation of said top surface portion above said foodstuff to from λ/15 to V6 of said microwave energy, said top surface portion being comprised of a dielectric substrate (40) and a plurality of metallic islands (48) forming an array dielectric having a relatively high dielectric constant.
Claim 33
Dependent Claim
34 words
The top (38) according to claim 27 further characterized by the total surface area of said metallic islands (48) is between 50 and 80 percent of the surface area of said top surface portion.
References Cited (Backward Citations)
No citation records indexed.
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