US2504109A - Dielectric heating with cavity resonator - Google Patents

Dielectric heating with cavity resonator Download PDF

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US2504109A
US2504109A US701300A US70130046A US2504109A US 2504109 A US2504109 A US 2504109A US 701300 A US701300 A US 701300A US 70130046 A US70130046 A US 70130046A US 2504109 A US2504109 A US 2504109A
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end wall
work
wall
dielectric heating
chamber
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US701300A
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Thomas W Dakin
Carroll N Works
Fitzhugh W Boggs
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CBS Corp
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Westinghouse Electric Corp
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Priority to US107442A priority patent/US2608637A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
    • B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
    • B29C35/12—Dielectric heating
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/64—Heating using microwaves
    • H05B6/80—Apparatus for specific applications
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S264/00—Plastic and nonmetallic article shaping or treating: processes
    • Y10S264/46—Molding using an electrical heat

Definitions

  • Our invention broadly relates to dielectric heating apparatus; but more particularly relates to the application of cavity resonators to highfrequency dielectric heating apparatus.
  • An object of our invention is to provide dielectric heating apparatus including a resonant cavity, more specifically, a reentrant resonant cavity.
  • Another object of our invention is to provide a dielectric heating apparatus of a type described having a region with a high intensity electric field into which the material to be heattreated can be readily placed and removed.
  • a more particular object of our invention is to provide a dielectric heating apparatus comprising a resonant reentrant cavity having an outer shell at ground potential and a readily accessible work-receiving space inside the outer shell.
  • the shell protects an operator against exposure to the high-voltage parts of the equipment.
  • part of the outer shell is movable for loading the work-receiving space of the apparatus. This part must be restored in order to place the apparatus in proper operating condition.
  • the resonant cavity is provided with an inner central member having a face spaced from a parallel face of an end wall of the shell, the end wall being movable so as to permit the apparatus to be loaded and unloaded. This end wall is at a current nodal point so that the joint between it and the rest of the shell does not carry any considerable current, and a loose joint can be tolerated, although a close fit is recommended.
  • the resonant reentrant cavity takes the form of an injecting apparatus suitable for pre-heating or otherwise treating plastic material or the like, which is forced from the apparatus into a mold.
  • a part of the resonant cavity is provided with an injection nose or nozzle.
  • Figure 1 is a central longitudinal view, mostly 2 an injection equipment in accordance with our invention.
  • Fig. 4 is a sectional view substantially on the lines IV-IV of Fig. 3.
  • a resonant cavity or chamber of the reentrant type is shown.
  • This reentrant resonant cavity is indicated in its entirety by the reference numeral 2 and comprises an outer member or shell having a hollow longitudinal tubular wall 4 and opposite end walls 6 and 8, respectively.
  • the walls are preferably of metal so that the shell constitutes an outer metallic enclosure which can be readily grounded so as to be at ground potential.
  • the end wall 5 is unitary with an edge of the tubular wall 4, and has secured thereto, or is integral with, a solid metallic central member H! which coaxially extends into the tubular wall 4 and is symmetrically arranged with respect to it.
  • the other end wall 8 is snugly slidable inside the tubular wall 4 and can be forcibly moved to any desired distance from the central member ID so as to constitute a plunger.
  • the separation between the inner face or work surface I 2 of the end wall 8 and the facing transverse face or work surface 14 of the central member ID provides a work-receiving space in which dielectric work W, comprising a plastic or any other suitable dielectric, may be placed for heat-treatment under a pressure of a value determined by the force exerted on the outer side of the end wall 8.
  • This force is schematically indicated at Fig. 1 by the series of arrows and a plunger or rod 16. In order to resist this force, the other parts of the cavity would, of course, have to be braced.
  • the portions of the end wall 8 and the central member ID between which the work is held or pressed can be considered to be relatively insulated heating electrodes, such as are found in more conventional dielectric heating apparatus.
  • the electrode or end wall 8 can he slid into and out of the tubular wall 4 so that the dielectric heating equipment can be loaded and unloaded.
  • the upper portion of the equipment could be moved instead, or even the central member only slid through a hole in the end wall 6.
  • This last form has the disadvantage that the sliding joint will be at a current anti-nodal point so that unless an extremely good conductive connection exists across the joint, power would be lost unnecessarily.
  • the shell can be made of any suitable material but preferably it. should be designed so that. it will absorb littlegpower itself; To thisend, the cavity may be of'steel and provided with coatings of copper or silver or other metal of high conductivity and low permeability. If desired, however, the entire resonant cantycanbenaoe of copper.
  • the cavity resonator can be po-Weredby making it part of the tank circuit of an oscillator trey coupling a conductor loop for acapacitor plate to it in a customary manner.
  • the upperlimito'f the frequency at which the cavityresonator operates is governed by the size of the work to be -heat treated between faces I2 and M. For a given set of conditions, the less the capacity between ithe faces, the higher will be the frequency at which with? resonator will oscillate. v 7
  • the apparatus has an importantadvantage in .that it-provides a-highdegree of safety for operation because the outer shell constitutes: an engclosurawhich can easil be kept at-groundpotenr tion.
  • any suitable-safety devic would; be I attached to the movable wall; 8 nor interrupting the power to the cavity resonator i'wl ienever the wall-starts to move from the heatfirra n osiuqn- ,T-he cross-section of the reentrantcavity of'the ,resqnator can :beselected as desired.
  • FIG. 2 shows other features which have been
  • theiihsulatedjend or the central member ID is fprovided with an-annular outwardly projecting por-tionor flange '24 so as to be able to heat work :of larger surfaceor diameter.
  • the end wall '8 is .hinged, bya hinge 26, to the outer tubular wall! and can be'forcibly latched closed by a latch28.
  • Teachings of our invention are also applicable to injection; molding, andin -Fig. 3ap aratus of this typeis schematically indicated in its entirety by :thereference numeral 313.
  • a metallic streamlinedelectrode member 40 is-connected to the far-or insulated end offthe central tubular member 38 by spaced. metal connecting bars 42.
  • the end wallet is provided with anoutwardly directed. metallic nozzle id insulated from and spaced from the associated end of the electrode member 38 by a-stepped ringffi of insulation.
  • the inside .of the "nose M is provided. with a suit- ;ably. shaped face 'or. surfaceliifwhich cooperates with a-soniewha't s'iinilarlylshape'dface or surface 50. on the member 40. to form. a work-receiving space acrosslwhich.a'high-frequency voltage exists.
  • central member 3% is adapted to receive pellets or other suitable :plastic 'maten rs'z .which'can beiorced by;a--ram,-or .plunger'54in'to thework-receiving space between 'lthe faces 48 .andbllbffthenose ldandmember 42,
  • chamber having. outer. wallswincluding; 'an end -.-wa lland having-an innerz-reentrantiportion facing said end 'wall but spaced therefrom to provide :a work-receiving: space; said end wall: being Zmdvable with respectto said-reentr'ant portion and to other walls of said ch'ambefsosas to provide wall and having an inner reentrant portion facing said end wall but spaced therefrom to provide a work-receiving space, said end wall being movable with respect to said reentrant portion and to other walls of said chamber so as to provide an opening in said chamber for loading work into said space for heat-treatment and unloading said work after such heat-treatment, and a pressure-exerting means engaging the outside of said end wall for holding work between said end wall and said reentrant portion, said pressure-exerting means comprising a member connected to the outside of said end wall and applying pressure on the outside of said end wall.
  • Dielectric heating means comprising means providing a resonant chamber having means through which it may be electrically excited, said chamber having outer walls including an end wall and having an inner reentrant portion facing said end wall but spaced therefrom to provide a work-receiving space, said end wall being movable with respect to said reentrant portion and to other walls of said chamber so as to provide an opening in said chamber for loading work into said space for heat-treatment and unloading said work after such heat-treatment, and a pressure-exerting means engaging the outside of said end wall for holding work between said end wall and said reentrant portion, said outer walls comprising a tubular wall, and said end Wall slidably fitting inside of said tubular wall.
  • Dielectric heating means comprising means providing a resonant chamber having means through which it may be electrically excited, said chamber having outer walls including an end wall-portion and having an inner reentrant portion including an end wall-portion facing the first said end wall-portion but spaced therefrom to provide a work-receiving space, one of said end wall-portions being relatively movable with respect to the other and to other walls of said chamber so as to provide an opening in said chamber for loading work into said space for heat-treatment and unloading said work after such heat-treatment, and a pressure-exerting means engaging the outside of said movable end wall-portion for holding work pressed between said end wall-portions during heat-treatment of the work, said pressure-exerting means comprising a member connected to the outside surface of said movable end wall-portion applying pressure to the outside of said movable end wallportion.
  • Dielectric heating means comprising means providing a resonant chamber having means through which it may be electrically excited, said chamber having outer walls including an end wall-portion and having an inner reentrant portion including an end wall-portion facing the first said end wall-portion but spaced therefrom to provide a work-receiving space, one of said end wall-portions being relatively movable with respect to the other and to other walls of said chamber so as to provide an opening in said chamber for loading work into said space for heat-treatment and unloading said work after such heat-treatment, walls of said resonant chamber providing a tubular portion in which one of said end wall-portions is slidable, and a pressure-exerting member associated with the outside of said slidable end wall-portion applying pressure thereto during heat-treatment of the work in said space.

Description

Patented Apr. 18, 1950 UNITED STATES PATENT OFFICE DIELECTRIC HEATING WITH CAVITY RESONATOR Application October 4, 1946, Serial No. 701,300
Claims.
Our invention broadly relates to dielectric heating apparatus; but more particularly relates to the application of cavity resonators to highfrequency dielectric heating apparatus.
An object of our invention is to provide dielectric heating apparatus including a resonant cavity, more specifically, a reentrant resonant cavity.
Another object of our invention is to provide a dielectric heating apparatus of a type described having a region with a high intensity electric field into which the material to be heattreated can be readily placed and removed.
A more particular object of our invention is to provide a dielectric heating apparatus comprising a resonant reentrant cavity having an outer shell at ground potential and a readily accessible work-receiving space inside the outer shell. The shell protects an operator against exposure to the high-voltage parts of the equipment.
In one form of our invention, part of the outer shell is movable for loading the work-receiving space of the apparatus. This part must be restored in order to place the apparatus in proper operating condition. In this embodiment, the resonant cavity is provided with an inner central member having a face spaced from a parallel face of an end wall of the shell, the end wall being movable so as to permit the apparatus to be loaded and unloaded. This end wall is at a current nodal point so that the joint between it and the rest of the shell does not carry any considerable current, and a loose joint can be tolerated, although a close fit is recommended.
In another embodiment of our invention, which forms the subject matter of our divisional case, Serial No. 107,442, filed July 26, 1949, the resonant reentrant cavity takes the form of an injecting apparatus suitable for pre-heating or otherwise treating plastic material or the like, which is forced from the apparatus into a mold. In such an embodiment, a part of the resonant cavity is provided with an injection nose or nozzle.
Features, innovations and objects of our invention, in addition to the foregoing, will be dis-,
cernible from the following description which is to be taken in conjunction with the accompanying schematic drawing in which:
Figure 1 is a central longitudinal view, mostly 2 an injection equipment in accordance with our invention, and
Fig. 4 is a sectional view substantially on the lines IV-IV of Fig. 3.
In the embodiment shown in Fig. 1, a resonant cavity or chamber of the reentrant type is shown. This reentrant resonant cavity is indicated in its entirety by the reference numeral 2 and comprises an outer member or shell having a hollow longitudinal tubular wall 4 and opposite end walls 6 and 8, respectively. The walls are preferably of metal so that the shell constitutes an outer metallic enclosure which can be readily grounded so as to be at ground potential. The end wall 5 is unitary with an edge of the tubular wall 4, and has secured thereto, or is integral with, a solid metallic central member H! which coaxially extends into the tubular wall 4 and is symmetrically arranged with respect to it. The other end wall 8 is snugly slidable inside the tubular wall 4 and can be forcibly moved to any desired distance from the central member ID so as to constitute a plunger. The separation between the inner face or work surface I 2 of the end wall 8 and the facing transverse face or work surface 14 of the central member ID provides a work-receiving space in which dielectric work W, comprising a plastic or any other suitable dielectric, may be placed for heat-treatment under a pressure of a value determined by the force exerted on the outer side of the end wall 8. This force is schematically indicated at Fig. 1 by the series of arrows and a plunger or rod 16. In order to resist this force, the other parts of the cavity would, of course, have to be braced.
When the cavity resonator 2 is made to resonate, a current anti-node will be at the end wall 6. A high voltage will exist between the separated faces l2 and M at the other end of the cavity resonator, and this high voltage will dielectrically heat any work between the faces.
The portions of the end wall 8 and the central member ID between which the work is held or pressed can be considered to be relatively insulated heating electrodes, such as are found in more conventional dielectric heating apparatus. The electrode or end wall 8 can he slid into and out of the tubular wall 4 so that the dielectric heating equipment can be loaded and unloaded. However, it is obvious that the upper portion of the equipment could be moved instead, or even the central member only slid through a hole in the end wall 6. This last form, however, has the disadvantage that the sliding joint will be at a current anti-nodal point so that unless an extremely good conductive connection exists across the joint, power would be lost unnecessarily.
The shell can be made of any suitable material but preferably it. should be designed so that. it will absorb littlegpower itself; To thisend, the cavity may be of'steel and provided with coatings of copper or silver or other metal of high conductivity and low permeability. If desired, however, the entire resonant cantycanbenaoe of copper.
The cavity resonator can be po-Weredby making it part of the tank circuit of an oscillator trey coupling a conductor loop for acapacitor plate to it in a customary manner. The upperlimito'f the frequency at which the cavityresonator operates is governed by the size of the work to be -heat treated between faces I2 and M. For a given set of conditions, the less the capacity between ithe faces, the higher will be the frequency at which with? resonator will oscillate. v 7
The apparatus has an importantadvantage in .that it-provides a-highdegree of safety for operation because the outer shell constitutes: an engclosurawhich can easil be kept at-groundpotenr tion. T-Asafur'ther precaution, any suitable-safety devic would; be I attached to the movable wall; 8 nor interrupting the power to the cavity resonator i'wl ienever the wall-starts to move from the heatfirra n osiuqn- ,T-he cross-section of the reentrantcavity of'the ,resqnator can :beselected as desired. -T-hemost ;convenientjform is to make both the central memllland the tubular member t circular and con- -cent1ic, In suchase, the endwalls -6. and 8 would necessarily be round discs. However, we
{hate usedacavity resonator in which'the central gmern -ber and outer tubular member; were square incross-section, and had their-facing sides a li l i a. v n
l i an indication of the operation of our invention, wen-have heated in; a -matter of seconds, *a "plastimpreform 9 india meter, 2V thiclc and ihavingf a loss factor of ..6 to Lain-areentrant resonantcavity, of a type shown in Fig. ':1,; which was square inv eross-s eetiorr and had the following -dinien sionsj inside overall length -30", central in mb'er =12 squareson 'the outside, outer tubular ber :18 sduareon the inside, I This reentrant I eso'nantc'avity operated at the frequencies-from ith the, electrode surfaces or faces l-2 and l4 that, FtheIVoltag eP between them .will be greatestrat l'the enter andbecomes progressively smaller be- "their circumference or periphery. With ifiadfcircular electrode surfaces, the V'Oltagebetween any two. longitudinally aligned points on the :lectfodesurfaces l k-andlll will-depend on the ;radial' distance .from'the axis or center. -A.good
iapprbximauoa ofithe voltage distribution canbe obtained from the .following equation:
.rWhQI'e Emax'lS the-voltage-across the two center pointsofthe 'surfaces'e'i's the dielectric constant *of-thework; x is-the wave length of "theoscili'a- --tions,an-d is the voltage 'at the distance; r,
from the center.
i The amount of heating per unit volumeofwork 3 variesas the square of the voltage :so ithat the radial voltage variation I may in some cases cause non-uniform heating. =-Ifr the variation large enough to v be; objectionable, 'amore uniform heat- .ing can. be obtained --by i dishing outone iofwthe electrode surfaces as indicated at 20 in the emthe facing heating surfaces will be partially ab- "s'orbed in the filling 22, and the remainder in modified from the embodiment of Fig. 1.
the wornw.
'Fig. 2 shows other features which have been Thus, theiihsulatedjend or the central member ID is fprovided with an-annular outwardly projecting por-tionor flange '24 so as to be able to heat work :of larger surfaceor diameter. Also, the end wall '8 is .hinged, bya hinge 26, to the outer tubular wall! and can be'forcibly latched closed by a latch28.
Teachings of our invention are also applicable to injection; molding, andin -Fig. 3ap aratus of this typeis schematically indicated in its entirety by :thereference numeral 313. :It-comprisesa metallic reentrant cavity havinganouter tubular wall 3-2, an annularfend wall. 3d and an opposite annular transverse closing endwalle fi. Extending from the inner edge (if-the endv wall '3 is a hollow central tubular member 38. A metallic streamlinedelectrode member 40 is-connected to the far-or insulated end offthe central tubular member 38 by spaced. metal connecting bars 42.
=The end wallet is provided with anoutwardly directed. metallic nozzle id insulated from and spaced from the associated end of the electrode member 38 by a-stepped ringffi of insulation. The inside .of the "nose M is provided. with a suit- ;ably. shaped face 'or. surfaceliifwhich cooperates with a-soniewha't s'iinilarlylshape'dface or surface 50. on the member 40. to form. a work-receiving space acrosslwhich.a'high-frequency voltage exists. The 'insidebf the. central member 3% is adapted to receive pellets or other suitable :plastic 'maten rs'z .which'can beiorced by;a--ram,-or .plunger'54in'to thework-receiving space between 'lthe faces 48 .andbllbffthenose ldandmember 42,
. chamber having. outer. wallswincluding; 'an end -.-wa lland having-an innerz-reentrantiportion facing said end 'wall but spaced therefrom to provide :a work-receiving: space; said end wall: being Zmdvable with respectto said-reentr'ant portion and to other walls of said ch'ambefsosas to provide wall and having an inner reentrant portion facing said end wall but spaced therefrom to provide a work-receiving space, said end wall being movable with respect to said reentrant portion and to other walls of said chamber so as to provide an opening in said chamber for loading work into said space for heat-treatment and unloading said work after such heat-treatment, and a pressure-exerting means engaging the outside of said end wall for holding work between said end wall and said reentrant portion, said pressure-exerting means comprising a member connected to the outside of said end wall and applying pressure on the outside of said end wall.
3. Dielectric heating means comprising means providing a resonant chamber having means through which it may be electrically excited, said chamber having outer walls including an end wall and having an inner reentrant portion facing said end wall but spaced therefrom to provide a work-receiving space, said end wall being movable with respect to said reentrant portion and to other walls of said chamber so as to provide an opening in said chamber for loading work into said space for heat-treatment and unloading said work after such heat-treatment, and a pressure-exerting means engaging the outside of said end wall for holding work between said end wall and said reentrant portion, said outer walls comprising a tubular wall, and said end Wall slidably fitting inside of said tubular wall.
1. Dielectric heating means comprising means providing a resonant chamber having means through which it may be electrically excited, said chamber having outer walls including an end wall-portion and having an inner reentrant portion including an end wall-portion facing the first said end wall-portion but spaced therefrom to provide a work-receiving space, one of said end wall-portions being relatively movable with respect to the other and to other walls of said chamber so as to provide an opening in said chamber for loading work into said space for heat-treatment and unloading said work after such heat-treatment, and a pressure-exerting means engaging the outside of said movable end wall-portion for holding work pressed between said end wall-portions during heat-treatment of the work, said pressure-exerting means comprising a member connected to the outside surface of said movable end wall-portion applying pressure to the outside of said movable end wallportion.
5. Dielectric heating means comprising means providing a resonant chamber having means through which it may be electrically excited, said chamber having outer walls including an end wall-portion and having an inner reentrant portion including an end wall-portion facing the first said end wall-portion but spaced therefrom to provide a work-receiving space, one of said end wall-portions being relatively movable with respect to the other and to other walls of said chamber so as to provide an opening in said chamber for loading work into said space for heat-treatment and unloading said work after such heat-treatment, walls of said resonant chamber providing a tubular portion in which one of said end wall-portions is slidable, and a pressure-exerting member associated with the outside of said slidable end wall-portion applying pressure thereto during heat-treatment of the work in said space.
THOMAS W. DAKIN. CARROLL N. WORKS. FITZHUGH BOGGS.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS FOREIGN PATENTS Country Date Great Britain Sept. 5, 1946 Number Number
US701300A 1946-10-04 1946-10-04 Dielectric heating with cavity resonator Expired - Lifetime US2504109A (en)

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US2612596A (en) * 1947-02-18 1952-09-30 Raytheon Mfg Co Microwave heating
US2684433A (en) * 1952-08-05 1954-07-20 Nat Cylinder Gas Co Voltage control for high-frequency heating electrodes
US2711468A (en) * 1951-12-28 1955-06-21 Nat Cylinder Gas Co Dielectric heating tunnels
US2712050A (en) * 1951-12-27 1955-06-28 Nat Cylinder Gas Co Flux guide and gate arrangements
US2714070A (en) * 1950-04-04 1955-07-26 Raytheon Mfg Co Microwave heating apparatus and method of heating a food package
US2713697A (en) * 1949-07-27 1955-07-26 Gen Electric Molding machine
US2732471A (en) * 1956-01-24 sweets
US2732474A (en) * 1956-01-24 ellsworth
US2747067A (en) * 1953-08-13 1956-05-22 Nat Cylinder Gas Co Voltage determining arrangement for dielectric heaters
US2762893A (en) * 1952-07-17 1956-09-11 Gen Motors Corp Electronic oven with liquid collector
US2765387A (en) * 1953-03-30 1956-10-02 Nat Cylinder Gas Co Dielectric heating system
US2765388A (en) * 1953-03-30 1956-10-02 Nat Cylinder Gas Co Apparatus for controlling oscillator grid drive
US2783346A (en) * 1954-03-26 1957-02-26 Nat Cylinder Gas Co High-frequency heating applicators
US2783349A (en) * 1954-03-26 1957-02-26 Nat Cylinder Gas Co High-frequency heating applicators
US2783344A (en) * 1954-03-26 1957-02-26 Nat Cylinder Gas Co Dielectric heating systems and applicators
US2783345A (en) * 1954-03-26 1957-02-26 Nat Cylinder Gas Co High-frequency heating applicators
US2783348A (en) * 1954-03-26 1957-02-26 Nat Cylinder Gas Co High-frequency heating applicators
US2816034A (en) * 1951-03-10 1957-12-10 Wilson & Co Inc High frequency processing of meat and apparatus therefor
US2830162A (en) * 1954-06-22 1958-04-08 Raytheon Mfg Co Heating method and apparatus
US3344363A (en) * 1965-02-12 1967-09-26 Commissariat Energie Atomique Cavity, wave guide and klystron interaction space form a resonant circuit
JPS4822799B1 (en) * 1970-08-06 1973-07-09
US20080068111A1 (en) * 2006-09-20 2008-03-20 Jan Hesselbarth Re-entrant resonant cavities, filters including such cavities and method of manufacture

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US2179261A (en) * 1937-08-11 1939-11-07 Bell Telephone Labor Inc Method and apparatus for heating dielectric materials
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US2370883A (en) * 1942-07-29 1945-03-06 Reed Prentice Corp Apparatus for heating materials for molding
US2410656A (en) * 1943-06-24 1946-11-05 Rca Corp Tuned ultra high frequency transformer
GB580374A (en) * 1944-03-16 1946-09-05 British Insulated Cables Ltd Improvements in apparatus for heating by high frequency electric energy

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2732471A (en) * 1956-01-24 sweets
US2732474A (en) * 1956-01-24 ellsworth
US2612596A (en) * 1947-02-18 1952-09-30 Raytheon Mfg Co Microwave heating
US2713697A (en) * 1949-07-27 1955-07-26 Gen Electric Molding machine
US2714070A (en) * 1950-04-04 1955-07-26 Raytheon Mfg Co Microwave heating apparatus and method of heating a food package
US2816034A (en) * 1951-03-10 1957-12-10 Wilson & Co Inc High frequency processing of meat and apparatus therefor
US2712050A (en) * 1951-12-27 1955-06-28 Nat Cylinder Gas Co Flux guide and gate arrangements
US2711468A (en) * 1951-12-28 1955-06-21 Nat Cylinder Gas Co Dielectric heating tunnels
US2762893A (en) * 1952-07-17 1956-09-11 Gen Motors Corp Electronic oven with liquid collector
US2684433A (en) * 1952-08-05 1954-07-20 Nat Cylinder Gas Co Voltage control for high-frequency heating electrodes
US2765387A (en) * 1953-03-30 1956-10-02 Nat Cylinder Gas Co Dielectric heating system
US2765388A (en) * 1953-03-30 1956-10-02 Nat Cylinder Gas Co Apparatus for controlling oscillator grid drive
US2747067A (en) * 1953-08-13 1956-05-22 Nat Cylinder Gas Co Voltage determining arrangement for dielectric heaters
US2783346A (en) * 1954-03-26 1957-02-26 Nat Cylinder Gas Co High-frequency heating applicators
US2783349A (en) * 1954-03-26 1957-02-26 Nat Cylinder Gas Co High-frequency heating applicators
US2783344A (en) * 1954-03-26 1957-02-26 Nat Cylinder Gas Co Dielectric heating systems and applicators
US2783345A (en) * 1954-03-26 1957-02-26 Nat Cylinder Gas Co High-frequency heating applicators
US2783348A (en) * 1954-03-26 1957-02-26 Nat Cylinder Gas Co High-frequency heating applicators
US2830162A (en) * 1954-06-22 1958-04-08 Raytheon Mfg Co Heating method and apparatus
US3344363A (en) * 1965-02-12 1967-09-26 Commissariat Energie Atomique Cavity, wave guide and klystron interaction space form a resonant circuit
JPS4822799B1 (en) * 1970-08-06 1973-07-09
US20080068111A1 (en) * 2006-09-20 2008-03-20 Jan Hesselbarth Re-entrant resonant cavities, filters including such cavities and method of manufacture
US7570136B2 (en) * 2006-09-20 2009-08-04 Alcatel-Lucent Usa Inc. Re-entrant resonant cavities, filters including such cavities and method of manufacture

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