US4005301A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microwave heat treating furnace
Assignee: Bpifrance Financement SA
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Filing: 1975-06-20
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Granted: 1977-01-25
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Expires: 1995-06-20
Abstract
Abstract A microwave furnace having a tunnel-like structure within which are arranged paired coherent sources of electromagnetic radiation that develop electromagnetic fields that have an interference pattern in which the average density of electromagnetic waves in each cross section of the furance is substantially constant. The paired coherent sources are box horns with each pair connected to a corresponding microwave generator that applies its microwave energy directly to one of the box horns of the pair and applies it through a phase shifter to the other box horn of the pair. The phase shifter shifts the relative phase shift cylically and effects for all points of each cross section an average valve of electromagnetic energy density that is constant over a cycle of variation of each phase shift. The box horns are arranged aligned on opposite sides of the longitudinal axis of the tunnel-like furnace with the radiation openings thereof aligned and extending in the longitudinal direction of the furnace.
Inventors
- 👤 Leo Y. Thourel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:33
CPC Classifications
H; H05; H05B; H05B6/00; H05B6/64; H05B6/72; H05B6/78
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
102 words
Tunnel furnace for microwave frequency heating, comprising, a tunnel-shaped enclosure through which in operation articles to be treated are caused to move in longitudinal direction of the tunnel-shaped structure; paired coherent sources of microwave electromagnetic radiation coupled to develop in cross sections of the tunnel-shaped enclosure electromagnetic fields; a phase shifter connected to said sources and which is variable in time to vary the relative phase shift of said coherent sources cyclically to effect for all points of each cross section of said tunnel-like structure an average value of electromagnetic energy density constant over a cycle of variation of a phase shift.
Claim 2
Dependent Claim
102 words
Tunnel furnace for microwave frequency heating, comprising, a tunnel-shaped enclosure through which in operation articles to be treated are caused to move in longitudinal direction of the tunnel-shaped structure; paired coherent sources of microwave electromagnetic radiation coupled to develop in cross sections of the tunnel-shaped enclosure electromagnetic fields; a phase shifter connected to said sources and which is variable in time to vary the relative phase shift of said coherent sources cyclically to effect for all points of each cross section of said tunnel-like structure an average value of electromagnetic energy density constant over a cycle of variation of a phase shift.
Claim 3
Dependent Claim
29 words
Tunnel furnace according to claim 1, in which said phase shifter comprises means to vary the relative phase shift of the coherent sources of radiation between zero and 180°.
Claim 4
Dependent Claim
26 words
Tunnel furnace according to claim 2, in which said means in said phase shifter comprises means to produce a sinusoidal variation of the relative phase shift.
Claim 5
Dependent Claim
33 words
Tunnel furnace according to claim 1, in which said phase shifter comprises means to produce a variation of the phase shift of a frequency at least equal to a few cycles per second.
Claim 6
Dependent Claim
54 words
Tunnel furnace according to claim 1, including other paired coherent sources of electromagnetic radiation similar to the first-mentioned coherent sources and coupled transversely in pairs, the pairs being substantially uniformly distributed along the tunnel-shaped enclosure and each pair of coherent sources having a phase shifter connected thereto constructed similarly to the first-mentioned phase shifter.
Claim 7
Dependent Claim
48 words
Tunnel furnace according to claim 5, for each pair of coherent sources of electromagnetic radiation a microwave frequency generator connected to discharge directly into one of the sources of the pair and connected to discharge via a corresponding phase shifter into the other coherent source of the pair.
Claim 8
Dependent Claim
31 words
Tunnel furnace according to claim 6, in which each source of electromagnetic radiation is a linear source, of the slotted wave guide type, arranged in the longitudinal direction of the enclosure.
Claim 9
Dependent Claim
26 words
Tunnel furnace according claim 6, in which each source of electromagnetic radiation is an over-dimensioned wave guide consisting of a box horn with a radiation opening.
Claim 10
Dependent Claim
49 words
Tunnel furnace according to claim 8 in which box horns of the different pairs of coherent sources are arranged in the tunnel-like enclosure in such a manner that their radiant openings are aligned along two longitudinal lines on opposite sides of a longitudinal axis of said tunnel like structure.
Claim 11
Dependent Claim
38 words
Tunnel furnace according to claim 8 in which short-circuit pillars are arranged within each box horn disposed to make the amplitude of radiation waves of the electromagnetic radiation uniform along the radiation opening of the corresponding box horn.
Claim 12
Dependent Claim
141 words
A microwave tunnel furnace comprising, means defining a tunnel enclosure having open ends, at least two sources of microwave energy being disposed opposite to each other in said tunnel structure in spaced relationship to develop within said tunnel structure an electromagnetic field; each of said coherent sources comprising two radiators for radiating electromagnetic waves, a microwave generator connected to apply microwave electromagnetic radiation directly to one of said radiators, a phase shifter connected between the microwave generator and the other of said radiators to receive said electromagnetic radiation from said microwave generator and apply it to the other of said radiators for varying the relative phase of said two radiators to effect for all points of each cross section of the tunnel-like structure an average value of the electromagnetic radiator density constant over a cycle of variation of a phase shift.
Claim 13
Dependent Claim
141 words
A microwave tunnel furnace comprising, means defining a tunnel enclosure having open ends, at least two sources of microwave energy being disposed opposite to each other in said tunnel structure in spaced relationship to develop within said tunnel structure an electromagnetic field; each of said coherent sources comprising two radiators for radiating electromagnetic waves, a microwave generator connected to apply microwave electromagnetic radiation directly to one of said radiators, a phase shifter connected between the microwave generator and the other of said radiators to receive said electromagnetic radiation from said microwave generator and apply it to the other of said radiators for varying the relative phase of said two radiators to effect for all points of each cross section of the tunnel-like structure an average value of the electromagnetic radiator density constant over a cycle of variation of a phase shift.
Claim 14
Dependent Claim
32 words
A microwave tunnel furnace according to claim 11, including means to transport articles to be treated in said tunnel-like structure in a longitudinal direction of said tunnel-like structure through said electromagnetic field.
Claim 15
Dependent Claim
43 words
A microwave tunnel furnace according to claim 11, in which each radiator comprises a box horn, waveguide means connecting said microwave generator to said one radiator and to said phase shifter independently and a waveguide connecting said phase shifter to said other radiator.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-01-25 | 1980-07-26 | 1981-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-01-25 | 1984-07-26 | 1985-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-01-25 | 1988-07-26 | 1989-01-25 | $7700.00 | Window Closed / Lapsed |