US4259561A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microwave applicator
Assignee: Bpifrance Financement SA
•
Filing: 1978-05-01
•
Granted: 1981-03-31
•
Expires: 1998-05-01
Abstract
Abstract The invention provides a microwave feeder or applicator, that is to say a resonant chamber for coupling to a source of microwaves, arranged for the microwave treatment of a sample of material, comprising two main conductive walls extending parallel to a common axial direction and each having two projections and a central part joining the two projections, the projections of the two walls facing one another in pairs whereas the central parts of the two walls likewise face one another and define a region in which there is a local increase in the distance between the two main walls; a first conductive end wall forming a short-circuit and extending in a plane forming a cross-section of the main walls; a second conductive end wall forming a second short-circuit extending in a plane forming a cross-section of the main walls, and a coupling means for supplying microwave energy to the feeder, the dimensions of the cavity formed by the main end walls being arranged so that the cavity resonates almost exclusively in the TE 11 mode, where the electric field is oriented along the cross-section of the main walls.
Inventors
- 👤 Georges Roussy
- 👤 Andre-Jean Berteaud
- 👤 Jean-Marie Thiebaut
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 19:37
CPC Classifications
H; H01; H01P; H01P7/00; H01P7/06; H05; H05B; H05B6/00; H05B6/64; H05B6/6402; H05B6/70; H05B6/705; H05B6/707; H05B6/80; Y; Y02; Y02B; Y02B40/00
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
167 words
A microwave applicator comprising two main conductive walls extending parallel to a common axial direction and each having two lateral projections and a central part joining the two projections, the projections of the two walls facing one another in pairs whereas the central parts of the two walls likewise face one another and are transversely protruding away from each other to define a central expansion therebetween; a first conductive end wall forming a short-circuit and extending in a plane forming a cross-section of the main walls; a second conductive end wall forming a second short-circuit extending in a plane forming a cross-section of the main walls, sample holding means adapted to support a sample transversely within the applicator, and a coupling means for supplying microwave energy to the applicator, the dimensions of the cavity formed by the main and end walls being arranged so that the cavity resonates substantially in the TE 11 mode, where the electric field is oriented along the cross-section of the main walls.
Claim 2
Dependent Claim
167 words
A microwave applicator comprising two main conductive walls extending parallel to a common axial direction and each having two lateral projections and a central part joining the two projections, the projections of the two walls facing one another in pairs whereas the central parts of the two walls likewise face one another and are transversely protruding away from each other to define a central expansion therebetween; a first conductive end wall forming a short-circuit and extending in a plane forming a cross-section of the main walls; a second conductive end wall forming a second short-circuit extending in a plane forming a cross-section of the main walls, sample holding means adapted to support a sample transversely within the applicator, and a coupling means for supplying microwave energy to the applicator, the dimensions of the cavity formed by the main and end walls being arranged so that the cavity resonates substantially in the TE 11 mode, where the electric field is oriented along the cross-section of the main walls.
Claim 3
Dependent Claim
83 words
A microwave applicator according to claim 1, wherein the dimensions of the said central expansion between the main walls are chosen, with respect to the distance between the facing projections of the main walls, to give preference only to the TE 11 and TM 11 modes, and the distance between the conductive end walls is made substantially equal to an integral multiple of the half wavelength associated with the TE 11 mode, so that the applicator resonates only at the TE 11 mode.
Claim 4
Dependent Claim
30 words
A microwave applicator according to claim 1 wherein the central parts of the main walls are similar channels and the cross-sections of the projections are straight lines in parallel pairs.
Claim 5
Dependent Claim
64 words
A microwave applicator according to claim 3, wherein the channels are identical and U-shaped, and the dimensions of the channels substantially satisfy the following conditions: ##EQU2## 2L denoting the common length of the channels, b denoting the maximum distance between the main walls taken at the bottom of the channels and c denoting the distance between the respectively facing projections from the main walls.
Claim 6
Dependent Claim
39 words
A microwave applicator according to claim 1, wherein the two main walls are symmetrical with respect to an axial plane, called the mode plane, parallel to their axial direction, and to the general direction of their major transverse dimension.
Claim 7
Dependent Claim
34 words
A microwave applicator according to claim 5, wherein each of the two main walls is symmetrical with respect to a second axial plane perpendicular to the mode plane and parallel to their axial direction.
Claim 8
Dependent Claim
41 words
A microwave applicator according to claim 5, wherein the distance between the respectively facing projections of the main walls are different on the two sides of the central parts resulting in an asymmetrical distribution of the electric field across the cross-section.
Claim 9
Dependent Claim
43 words
A microwave applicator according to claim 1, wherein the second conductive end wall is mounted for movement in the axial direction of the main walls, so that the applicator can be tuned to a fixed frequency in dependence on the microwave processing conditions.
Claim 10
Dependent Claim
51 words
A microwave applicator according to claim 1, which includes two side walls extending in the axial direction and joining the free ends of the main walls between the two end walls, and wherein an orifice is provided in at least one of the lateral walls for the admittance of a sample.
Claim 11
Dependent Claim
22 words
A microwave applicator according to claim 9, wherein the two lateral walls each have similar orifices through which a sample can pass.
Claim 12
Dependent Claim
28 words
A microwave feeder applicator according to claim 9, wherein the two side walls extend perpendicular to the general direction of the major transverse dimension of the main walls.
Claim 13
Dependent Claim
42 words
A microwave applicator according to claim 1, wherein the sample holding means is adapted to support the sample between the two main walls and substantially equidistant therefrom, extending in a direction substantially perpendicular to the axial direction of the two main walls.
Claim 14
Dependent Claim
33 words
A microwave applicator according to claim 12, wherein the sample holding means is adapted for a sample which is substantially cylindrical and has either a circular base or a substantially regular polygonal base.
Claim 15
Dependent Claim
49 words
A microwave applicator according to claim 1, comprising a central wall extending along the axial direction of the main walls and perpendicular to the general direction of their major transverse dimensions, whereby the sample is held in the region of an intense electric field in operation of the applicator.
Claim 16
Dependent Claim
53 words
A microwave applicator according to claim 1, wherein at least one of the two end walls includes a groove parallel to the general direction of the major transverse dimension in cross-section of the main walls, thus preventing currents perpendicular to the main walls from flowing in the end walls and producing interfering modes.
Claim 17
Dependent Claim
35 words
A microwave applicator according to claim 1, wherein the microwave supply coupling means comprises at least one orifice formed in one wall of the applicator, and a supply wave guide is coupled to the orifice.
Claim 18
Dependent Claim
16 words
A microwave applicator according to claim 16, wherein the orifice is formed in one end wall.
Claim 19
Dependent Claim
25 words
A microwave applicator according to claim 16, wherein the orifice is formed at the center of the central part of one of the main walls.
Claim 20
Dependent Claim
36 words
A microwave applicator according to claim 16, including a coupling transition provided to ensure a progressive transition from the mode in the supply wave guide to the desired electromagnetic distribution in the applicator near the orifice.
Claim 21
Dependent Claim
26 words
A microwave applicator according to claim 16, wherein the orifice is formed on a side wall of the wave guide supplying microwave energy to the applicator.
Claim 22
Dependent Claim
48 words
A microwave applicator according to claim 20, wherein the end of the supplying wave guide is disposed shortly after the coupling, and a movable piston is provided in that end forming a short-circuit, the piston being movable so as to vary the microwave power transmitted to the applicator.
Claim 23
Dependent Claim
33 words
A microwave applicator according to claim 16, wherein the coupling comprises a set of small area orifices distributed in regular manner, at least statistically, over a portion of one of the applicator walls.
Claim 24
Dependent Claim
43 words
A microwave applicator according to claim 22, wherein the small area orifices are formed in one end wall of the applicator and the coupling transition ensures a progressive transition from the cross-section of the supplying wave guide to the cross-section of the applicator.
Claim 25
Dependent Claim
31 words
A microwave applicator according to claim 22, wherein the coupling comprises an auxiliary plate which is arranged to partly reflect microwaves and is disposed near the set of small area orifices.
Claim 26
Dependent Claim
15 words
A microwave applicator according to claim 24, wherein the auxiliary plate is made of Teflon.
Claim 27
Dependent Claim
21 words
A microwave applicator according to claim 24, wherein the auxiliary plate is conductive and is also formed with small area orifices.
Claim 28
Dependent Claim
16 words
A microwave applicator according to claim 16, wherein the coupling orifice is designed for inductive coupling.
References Cited (Backward Citations)
US2412446A
Cited
US2747137A
Cited
US3151230A
Cited
US3242304A
Cited
US3315187A
Cited
US3543199A
Cited
US3765985A
Cited
US3784777A
Cited
US3754111A
Cited
US3920945A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-03-30 | 1984-09-29 | 1985-03-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-30 | 1988-09-29 | 1989-03-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-30 | 1992-09-29 | 1993-03-31 | $7700.00 | Window Closed / Lapsed |