US3632945A
Expired / Lapsed
US
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System and method for heating material employing oversize waveguide applicator
Assignee: MICRODRY Inc A CORP OF KENTUCKY
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Filing: 1969-04-16
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Granted: 1972-01-04
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Expires: 1989-04-16
Abstract
Abstract A microwave heating applicator is provided in the form of a rectangular-type waveguide having dimensions a and b transverse of power flow through the guide. The b dimension is maintained less than one-half the free-space wavelength of the excitation frequency, lambda o; and the dimension a is enlarged beyond lambda o thereby reducing the attenuation constant for the applicator and the heating rate of the material being treated. The microwave power is transmitted through a treating zone in a first direction; and the electric field intensity varies, transverse of the direction of power flow, from a minimum at one side of the treating zone to a maximum at the center of the zone and back to a minimum at the other side of the treating zone. These sides of the treating zone define the dimension a; and the material is passed through the treating zone either along the direction of power flow or perpendicular to the direction of power flow, depending upon the application.
Inventors
- 👤 Ray M Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 17:31
CPC Classifications
H; H05; H05B; H05B6/00; H05B6/64; H05B6/78; H05B6/782; A; A23; A23B; A23B2/00; A23B2/05; A23B2/08
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
68 words
A system for applying microwave energy to material comprising a source of microwave energy at a wavelength, lambda o, waveguide applicator means having transverse dimensions, a and b, in a plane lying perpendicular to the flow of power therethrough, wherein b is less than about one-half lambda o and a is greater than lambda o and means coupling said source to said applicator means to excite the same.
Claim 2
Independent Claim
68 words
A system for applying microwave energy to material comprising a source of microwave energy at a wavelength, lambda o, waveguide applicator means having transverse dimensions, a and b, in a plane lying perpendicular to the flow of power therethrough, wherein b is less than about one-half lambda o and a is greater than lambda o and means coupling said source to said applicator means to excite the same.
Claim 3
Dependent Claim
52 words
The system of claim 1 wherein said dimension, a, defines the transverse width of a pair of opposing broadwalls extending in the direction of power flow and wherein at least one of said broadwalls defines a slot centered at about the transverse center thereof and extending in the direction of power flow.
Claim 4
Dependent Claim
68 words
The system of claim 1 wherein said dimension, a, defines the transverse width of a pair of opposing broadwalls extending in the direction of power flow and wherein each of said broadwalls defines a slot centered at about the transverse center thereof and extending in the direction of power flow and further comprising means for moving said material through said slots transverse of the direction of power flow.
Claim 5
Dependent Claim
59 words
The system of claim 3 wherein said applicator means is formed into a plurality of folds, each fold being an applicator section, and wherein all of said broadwalls define slots centered at about the transverse center thereof and extending in the direction of power flow, all of said slots being aligned to permit the passage of said material therethrough.
Claim 6
Dependent Claim
69 words
The system of claim 1 wherein said waveguide applicator means is defined by a first pair of opposing broadwalls extending in the direction of power flow and having a transverse dimension equal to a, and a second pair of opposing sidewalls extending in the direction of power flow and having a transverse dimension equal to b, and wherein said material is disposed between said broadwalls over an extended area.
Claim 7
Independent Claim
145 words
A system for applying heat to sheet material comprising source means generating microwave energy, waveguide means excited by said source principally in the TE10 mode whereby power flows along said waveguide means, said waveguide means having a rectangular transverse cross section providing a pair of opposing broadwalls separated by a distance of less than about one-half the free-space wavelength of the excitation frequency, and a pair of opposing sidewalls separated by a distance greater than the free-space wavelength of said excitation frequency, said opposing broadwalls defining a pair of slots extending along the centerline thereof in the direction of flow of power for receiving said material, and means supporting said material for moving the same through said pair of slots transverse of the flow of power through said waveguide means thereby to diminish the attenuation constant through said material in the direction of power flow.
Claim 8
Independent Claim
145 words
A system for applying heat to sheet material comprising source means generating microwave energy, waveguide means excited by said source principally in the TE10 mode whereby power flows along said waveguide means, said waveguide means having a rectangular transverse cross section providing a pair of opposing broadwalls separated by a distance of less than about one-half the free-space wavelength of the excitation frequency, and a pair of opposing sidewalls separated by a distance greater than the free-space wavelength of said excitation frequency, said opposing broadwalls defining a pair of slots extending along the centerline thereof in the direction of flow of power for receiving said material, and means supporting said material for moving the same through said pair of slots transverse of the flow of power through said waveguide means thereby to diminish the attenuation constant through said material in the direction of power flow.
Claim 9
Dependent Claim
64 words
The system of claim 6 wherein said waveguide means forms a plurality of separate applicator sections with power flowing in opposite directions in adjacent sections and corresponding broadwalls being parallel, the broadwalls of each applicator section defining a pair of slots extending along the centerline of said broadwalls in the direction of power flow, all of said slots being aligned to receive said material.
Claim 10
Dependent Claim
61 words
The system of claim 7 further comprising coupling waveguide means receiving power from said source and coupling the same to said waveguide means, said coupling waveguide means being symmetrical about a plane parallel to the direction of power flow and passing through the centers of said pair of slots to prevent excitation of TEmo modes where m is an even integer.
Claim 11
Dependent Claim
63 words
The system of claim 7 wherein the transverse width of said pair of opposing broadwalls is progressively diminished to define a taper while maintaining the separation between said broadwalls less than one-half the free-space wavelength of the excitation frequency, said taper being symmetrical about a plane parallel to the direction of power flow and passing through the centerlines of said pair of slots.
Claim 12
Dependent Claim
60 words
In a microwave heating system, the combination of a waveguide of rectangular type cross section excited in the TE10 mode and provided with a pair of opposing broadwalls having a width transverse of the direction of power flow greater than the free-space wavelength of the excitation frequency, and material in said waveguide between said broadwalls for dissipating microwave energy therein.
Claim 13
Dependent Claim
60 words
In a microwave heating system, the combination of a waveguide of rectangular type cross section excited in the TE10 mode and provided with a pair of opposing broadwalls having a width transverse of the direction of power flow greater than the free-space wavelength of the excitation frequency, and material in said waveguide between said broadwalls for dissipating microwave energy therein.
Claim 14
Dependent Claim
32 words
The system of claim 10 wherein said opposing broadwalls define parallel sides of said waveguide means separated by a distance less than about one-half of the free-space wavelength of said excitation frequency.
Claim 15
Independent Claim
147 words
A method of heating a matErial comprising: generating a microwave electric field having a free-space wavelength of predetermined dimension; confining said microwave field in a treating zone such that substantially the entire electric field vector lines thereof lie in a plane and the intensity of said field in said plane varies from a minimum at a first side of said zone through a maximum at a central location in said zone and thence to a minimum at a second side of said zone; transmitting power of said field in a direction perpendicular of said plane; and applying said microwave field to said material in said treating zone to heat the same while maintaining the spacing between said first and second minimum locations defining the sides of said treating zone greater than the free-space wavelength of said microwave field at least over a portion of said treating zone.
Claim 16
Independent Claim
147 words
A method of heating a matErial comprising: generating a microwave electric field having a free-space wavelength of predetermined dimension; confining said microwave field in a treating zone such that substantially the entire electric field vector lines thereof lie in a plane and the intensity of said field in said plane varies from a minimum at a first side of said zone through a maximum at a central location in said zone and thence to a minimum at a second side of said zone; transmitting power of said field in a direction perpendicular of said plane; and applying said microwave field to said material in said treating zone to heat the same while maintaining the spacing between said first and second minimum locations defining the sides of said treating zone greater than the free-space wavelength of said microwave field at least over a portion of said treating zone.
Claim 17
Dependent Claim
44 words
The method of claim 12 further comprising the step of maintaining the dimension of said treating zone extending transverse of the direction of power flow and transverse of the direction of said field lines less than one-half the free-space wavelength of said excitation frequency.
Claim 18
Independent Claim
173 words
A method of heating a material comprising: transmitting in a first direction through a treating zone microwave power provided by an electric field excited at a predetermined frequency and having field lines extending substantially entirely in a plane perpendicular to said first direction, the intensity of said field in said plane varying from a minimum at a first side of said treating zone through a maximum at an intermediate location in said treating zone and thence to said minimum as a second side of said treating zone; moving said material through said treating zone in a direction perpendicular to said first direction and through said maximum level of field intensity whereby said microwave power is transmitted through said material transverse of the direction of movement of said material through said treating zone; and maintaining the distance between said first and second sides of said treating zone at which said field intensity is at said minimum greater than the free-space wavelength of said excitation frequency over at least a portion of said treating zone.
Claim 19
Independent Claim
173 words
A method of heating a material comprising: transmitting in a first direction through a treating zone microwave power provided by an electric field excited at a predetermined frequency and having field lines extending substantially entirely in a plane perpendicular to said first direction, the intensity of said field in said plane varying from a minimum at a first side of said treating zone through a maximum at an intermediate location in said treating zone and thence to said minimum as a second side of said treating zone; moving said material through said treating zone in a direction perpendicular to said first direction and through said maximum level of field intensity whereby said microwave power is transmitted through said material transverse of the direction of movement of said material through said treating zone; and maintaining the distance between said first and second sides of said treating zone at which said field intensity is at said minimum greater than the free-space wavelength of said excitation frequency over at least a portion of said treating zone.
Claim 20
Dependent Claim
59 words
The method of claim 14 wherein said material is generally planar and said field lines are substantially parallel to each other in said treating zone and wherein said step of moving said material comprises passing said material through said treating zone in a direction parallel to said field lines and to said direction of transmission of said microwave power.
Claim 21
Dependent Claim
26 words
The method of claim 14 further comprising converging the spacing of said first and second sides of said treating zone in the direction of power flow.
Claim 22
Dependent Claim
36 words
The method of claim 14 further comprising the step of confining said field lines transverse of their direction of extension within less than one-half of the free-space wavelength of the excitation frequency in said treating zone.
Claim 23
Independent Claim
144 words
A method of heating a material comprising: transmitting microwave power through a treating zone in a first direction, said power being provided by an electric field excited at a predetermined frequency and having field lines substantially parallel to each other and within a plane perpendicular to said first direction, the intensity of said field in said plane along a line transverse of said field lines varying from a minimum at a first side of said treating zone through a maximum at an intermediate location in said treating zone and thence to a minimum at a second side of said treating zone; moving said material through said treating zone along said first direction; and maintaining said first and second sides of said treating zone at a distance greater than the free-space wavelength of said excitation frequency over at least a portion of said treating zone.
Claim 24
Independent Claim
144 words
A method of heating a material comprising: transmitting microwave power through a treating zone in a first direction, said power being provided by an electric field excited at a predetermined frequency and having field lines substantially parallel to each other and within a plane perpendicular to said first direction, the intensity of said field in said plane along a line transverse of said field lines varying from a minimum at a first side of said treating zone through a maximum at an intermediate location in said treating zone and thence to a minimum at a second side of said treating zone; moving said material through said treating zone along said first direction; and maintaining said first and second sides of said treating zone at a distance greater than the free-space wavelength of said excitation frequency over at least a portion of said treating zone.
Claim 25
Dependent Claim
26 words
The method of claim 18 further comprising confining said field along the direction of said field lines to less than one-half wavelength of the excitation frequency.
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) | 1975-01-03 | 1975-07-05 | 1976-01-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-03 | 1979-07-05 | 1980-01-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-03 | 1983-07-05 | 1984-01-04 | $7700.00 | Window Closed / Lapsed |