US3688068A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Continuous microwave heating or cooking system and method
Assignee: MICRODRY Inc A CORP OF KENTUCKY
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Filing: 1970-12-21
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Granted: 1972-08-29
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Expires: 1990-12-21
Abstract
Abstract A rectangular type wave guide applicator having a pair of opposing broadwalls separated by a distance b, is excited in principally the TE10 mode; and material being treated is conveyed through the applicator along the direction of power flow. The distance b, is maintained throughout the applicator to be less than half a wavelength of the excitation frequency so that only TEmo modes will propagate. Rejection filters are provided at the input and exit apertures through which the material is passed to prevent the escape of microwave energy without absorbing it. Air is circulated through the heating chamber for removing moisture and gases. A termination is provided downstream of the heating chamber in the form of a water load to absorb all microwave energy not absorbed in the material being treated to insure that the source sees a load which is substantially independent of variations in the amount of material being treated.
Inventors
- 👤 Ray M Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:47
CPC Classifications
H; H05; H05B; H05B6/00; H05B6/64; H05B6/78; H05B6/782
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
155 words
In a system for applying microwave energy to material having upper and lower extended surfaces, the combination comprising: a waveguide applicator providing a heating chamber having upper and lower opposing broadwalls lying in parallel planes extending in a generally horizontal direction and spaced to prevent the propagation of TEmn and TMmn modes where n is greater than zero, said waveguide applicator being symmetrical about a vertical plane extending along the direction of power flow to minimize excitation of TEmo modes where m is an even integer, support means supporting said material for carrying the same in a generally horizontal disposition through said heating chamber between said broadwalls with said upper and lower surfaces of said material extending substantially parallel to said broadwalls, and source means for energizing said applicator substantially entirely in the TE10 mode whereby the electric field vector impinging on the upper and lower extended surfaces of said material is not parallel thereto.
Claim 2
Dependent Claim
155 words
In a system for applying microwave energy to material having upper and lower extended surfaces, the combination comprising: a waveguide applicator providing a heating chamber having upper and lower opposing broadwalls lying in parallel planes extending in a generally horizontal direction and spaced to prevent the propagation of TEmn and TMmn modes where n is greater than zero, said waveguide applicator being symmetrical about a vertical plane extending along the direction of power flow to minimize excitation of TEmo modes where m is an even integer, support means supporting said material for carrying the same in a generally horizontal disposition through said heating chamber between said broadwalls with said upper and lower surfaces of said material extending substantially parallel to said broadwalls, and source means for energizing said applicator substantially entirely in the TE10 mode whereby the electric field vector impinging on the upper and lower extended surfaces of said material is not parallel thereto.
Claim 3
Dependent Claim
70 words
The system of claim 1 wherein said applicator further comprises input elbow means of rectangular cross section receiving power from said source for coupling said power to said waveguide heating chamber, said input elbow receiving said power in a generally vertical direction and transmitting the same in a generally horizontal direction to said heating chamber, one broadwall thereof defining an aperture for admitting passage of said material to said chamber.
Claim 4
Dependent Claim
22 words
The system of claim 2 further comprising rejection filter means adjacent said admitting aperture for preventing the passage of microwave energy therethrough.
Claim 5
Dependent Claim
15 words
The system of claim 3 further comprising means for circulating air through said heating chamber.
Claim 6
Dependent Claim
24 words
The system of claim 4 wherein the half sections of said heating chamber are separateable to permit access to the interior thereof for cleaning.
Claim 7
Dependent Claim
66 words
The system of claim 4 further comprising an output waveguide elbow of rectangular cross section receiving power from said heating chamber for transmitting the same in a generally vertical direction, one broadwall of said output elbow defining an aperture for admitting the egress of said material, and termination means receiving power from said output elbow and including a load for absorbing said power without substantial reflection.
Claim 8
Dependent Claim
29 words
The system of claim 6 further comprising output rejection filter means coupled to said output waveguide elbow adjacent said aperture for inhibiting the passage of said microwave energy therethrough.
Claim 9
Independent Claim
144 words
A system for applying microwave energy to a food product which has a generally uniform thickness along one direction comprising a rectangular waveguide having upper and lower broadwalls extending in a second direction; excitation means including a source of microwave energy coupled to said waveguide for energizing the same substantially entirely in the TE10 mode, said waveguide being symmetrical about a vertical plane extending in a direction of elongation of said broadwalls to inhibit the generation of electrical modes other than the TE10 mode; conveyor means supporting said product for moving the same within said broadwalls wherein extended surfaces of said product are generally parallel to said broAdwalls, said conveyor means moving said product in the direction of power flow within said waveguide while holding the direction of uniform thickness of said product substantially perpendicular to the direction of power flow of said waveguide.
Claim 10
Independent Claim
144 words
A system for applying microwave energy to a food product which has a generally uniform thickness along one direction comprising a rectangular waveguide having upper and lower broadwalls extending in a second direction; excitation means including a source of microwave energy coupled to said waveguide for energizing the same substantially entirely in the TE10 mode, said waveguide being symmetrical about a vertical plane extending in a direction of elongation of said broadwalls to inhibit the generation of electrical modes other than the TE10 mode; conveyor means supporting said product for moving the same within said broadwalls wherein extended surfaces of said product are generally parallel to said broAdwalls, said conveyor means moving said product in the direction of power flow within said waveguide while holding the direction of uniform thickness of said product substantially perpendicular to the direction of power flow of said waveguide.
Claim 11
Dependent Claim
40 words
The system of claim 8 wherein the broadwalls of said waveguide are spaced at a distance less than one-half of the free-space wave length of the excitation frequency to inhibit propagation of TEmn where n is greater than zero modes.
Claim 12
Dependent Claim
95 words
The system of claim 8 wherein said waveguide is in general U-shape form when viewed from the side, said waveguide defining a first input aperture in its lower broadwall receiving said product and a second output aperture in its lower broadwall through which the product is discharged from said waveguide, said system further including a rejection filter at said input and output apertures to reject the passage of microwave energy while permitting the passage of said product, and termination means downstream of the direction of power flow from said output aperture for absorbing remnant power.
Claim 13
Dependent Claim
116 words
In a process for treating with microwave energy a material having upper and lower surfaces, the steps of propagating microwave energy in the TE10 mode between upper and lower opposing broadwalls lying in parallel planes extending in a horizontal direction and spaced to prevent the propagation of TEmn and TMmn modes where n is greater than zero while avoiding excitation of TEmo modes where m is an even integer, and passing said material between said broadwalls with its said upper and lower surfaces extending substantially parallel to said broadwalls in the direction of said propagation of energy and substantially perpendicular to the electric field vector impinging on said upper and lower extended surfaces of said material.
Claim 14
Dependent Claim
116 words
In a process for treating with microwave energy a material having upper and lower surfaces, the steps of propagating microwave energy in the TE10 mode between upper and lower opposing broadwalls lying in parallel planes extending in a horizontal direction and spaced to prevent the propagation of TEmn and TMmn modes where n is greater than zero while avoiding excitation of TEmo modes where m is an even integer, and passing said material between said broadwalls with its said upper and lower surfaces extending substantially parallel to said broadwalls in the direction of said propagation of energy and substantially perpendicular to the electric field vector impinging on said upper and lower extended surfaces of said material.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-29 | 1976-02-28 | 1976-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-29 | 1980-02-28 | 1980-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-29 | 1984-02-28 | 1984-08-29 | $7700.00 | Window Closed / Lapsed |