US3251975A - Electrode for high frequency heating - Google Patents
Electrode for high frequency heating Download PDFInfo
- Publication number
- US3251975A US3251975A US289934A US28993463A US3251975A US 3251975 A US3251975 A US 3251975A US 289934 A US289934 A US 289934A US 28993463 A US28993463 A US 28993463A US 3251975 A US3251975 A US 3251975A
- Authority
- US
- United States
- Prior art keywords
- electrode
- high frequency
- electrodes
- contact
- metal wool
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000010438 heat treatment Methods 0.000 title claims description 10
- 239000002184 metal Substances 0.000 description 14
- 229910052751 metal Inorganic materials 0.000 description 14
- 210000002268 wool Anatomy 0.000 description 14
- 239000000463 material Substances 0.000 description 7
- 239000004020 conductor Substances 0.000 description 6
- 239000003989 dielectric material Substances 0.000 description 6
- 230000005684 electric field Effects 0.000 description 6
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 230000037431 insertion Effects 0.000 description 2
- 238000003780 insertion Methods 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
Images
Classifications
-
- 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
- H05B6/46—Dielectric heating
- H05B6/54—Electrodes
-
- 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
Definitions
- This invention relates to electrodes for applying high frequency electromagnetic energy to dielectric materials for heating purposes, and more particularly to electrodes which are suitable for the application of the high frequency energy to uneven surfaces such as concrete, rocks or like material.
- the electric field should spread out from the small-electrode so that the field intensity at a distance from the electrode is low. This requires that an electrode having a relatively large contact area be employed in conjunction with the small area of the field concentrating electrode.
- a further consideration is that too high a voltage gradient across the surface of the material being heated will result in surface arcing and power losses. It is also necessary that a low resistance connection be made between the small electrode and the surface to prevent local hot spots or arcing at this electrode.
- the electrode comprises a holder provided with a metal Wool of low resistance which acts as the intermediary conductor between the dielectric surface and the conductor of a high frequency energy supply source.
- FIGURE 1 is an electrode system incorporating the invention which is adapted to supply radio frequency energy between a drill hole and an outside surface of the dielectric material and,
- FIGURE 2 is an electrode system for applying radio frequency energy to spaced points on the surface of a dielectric material to be heated.
- a hole 10 is shown in a dielectric material 8, for instance, concrete, and high frequency electromagnetic energy is applied thereto by an electrode comprising a central conductor 1, which may be the center conductor of a coaxial cable, having a dishshaped end piece 5 with its open end facing the inner end of the drill hole.
- a metal wool 4, for instance copper, is squeezed between the piece 5 and the end of the drill hole and, due to its resilience, makes contact over the entire end surface of the drill hole.
- a further electrode 2 in the form of an annular trough faces the outer surface or wall of the dielectric material surrounding the central conductor 1.
- the annular trough electrode 2 is filled with a metal wool 4 which provides the contact between that electrode and the outer surface of material 8.
- Electrode 2 can, in itself or by additional means, prevent shattered material from flying out of the surface of the material.
- the central electrode 7 may be quite similar to electrode 5 of FIG. 1, and the annular electrode 6 may be similar to electrode 2.
- an electrode system such as shown in FIG- URE 1 can be provided with a retractable central electrode to allow for variations in hole depth and also allow use of the system on a relatively flat surface. necessary that one electrode, such as 2 or 6, be annular, but this is a preferred embodiment.
- two electrodes, similar to the central electrode 4, 5 of the unit shown in FIGURE 1 may be employed for the two active electrodes provided, of course, that the contact area of one electrode is greater than that of the other.
- Two drill holes are then provided to facilitate their use. In this manner a concentrated field can be set up in the material between the two drill holes.
- Apparatus employing high frequency electromag netic energy for heating a dielectric body, comprising an inner electrode having a resilient contact surface comprising a conductive metal wool, a spaced outer annular electrode concentric with said inner electrode and having a resilent contact surface comprising a conductive metal wool, said apparatus being positionable so that said inner electrode contact surface and said outer electrode contact surface bear against the surface of said body, and means for supplying said high frequency energy to said first and second electrodes thereby to establish an electric field in said body between said electrodes.
- Apparatus for fracturing a brittle dielectric body by means of high frequency electromagnetic energy comprising an inner and an outer electrode for applying said high frequency energy to said body, said outer electrode comprising an annular conductive member concentric with said inner electrode and having a resilient contact surface at one end thereof comprising a conductive metal wool, said inner electrode comprising an elongated conductive member longitudinally positioned within said outer electrode and having a dish-shaped portion at one end thereof, a conductive metal wool positioned within said dish-shaped portion so as to form a resilent area of contact with said dielectric body, and means for supplying said high frequency energy to said first and second electrodes thereby to establish an electric field in said body between said electrodes.
- Apparatus for fracturing a brittle dielectric body by means of high frequency electromagnetic energy comprising an inner and an outer electrode for applying said high frequency energy to said body, said outer electrode comprising an annular conductive member disposed in a plane and having a resilient contact surface at one end thereof comprising a conductive metal wool, said inner electrode comprising an elongated conductive member c0n centric with said outer electrode and radially spaced therefrom, said inner electrode extending beyond the plane of said outer electrode for insertion in a recess in said body and having a concave surface at its operative end, a conductive metal wool positioned within said concave surface portion so as to form a resilient area of contact with said dielectric body, and means for supplying said high frequency energy to said first and second electrodes thereby to establish an electric field in said body between said electrodes.
- Apparatus for fracturing a brittle dielectric body by means of high frequency electromagnetic energy com- It is not prising an inner and an outer electrode for applying said high frequency energy to said body, said outer electrode comprising an annular conductive member disposed in a plane and having a resilient contact surface atone end thereof comprising a conductive metal wool, said inner electrode comprising an elongated conductive member concentric with said outer electrode and radially spaced therefrom, said inner electrode extending beyond the plane of said outer electrode for insertion in a recess in said body and having a concave surface at its operative end, a conductive metal wool positioned within said concave surface portion so as to form a resilient area of contact with said dielectric body, said outer electrode having an area of contact with said dielectric body which is greater than the contact area of said inner electrode with said body, said apparatus further comprising means for longitudinally moving said inner electrode With respect to said outer electrode at right angles to the plane of contact of said outer electrode thereby to alter the dis tance said inner electrode
- Apparatus employing high frequency electromagnetic energy for heating a dielectric body comprising first and second spaced apart electrodes for applying said high frequency energy to said body, said first electrode comprising a conductive member terminating in an end portion comprising a conductive metal wool in the form of a porous mass of randomly oriented metal fibers arranged to provide a low resistance resilient contact area between said first electrode and a portion of said body having a very irregular shape, said second electrode comprising a conductive member terminating in a body contacting portion having a surface contact area which is substantially larger than the contact area of said first electrode, said second electrode being arranged to contact a portion of said body spaced from said resilient contact area, and
- Apparatus employing high frequency electromagnetic energy for heating a dielectric body, comprising an inner and an outer electrode for applying said high frequency energy to said body, said inner electrode comprising a conductive member having a resilient contact surface provided at one end thereof comprising a highly porous conductive metal wool, said outer electrode comprising an annular conductive member concentric with said inner electrode and arranged to contact -a portion of said body spaced apart from the point of contact of said inner electrode with said body, and means for supplying said high frequency energy to said first and second electrodes thereby to establish an electric field in said body between said electrodes.
Description
May 17, 1966 E. H. HUGENHOLTZ ELECTRODE FOR HIGH FREQUENCY HEATING Filed June 24 INVENTOR. EDUARD H. HUGENHOLTZ BY AGENT United States Patent 54, 7 Claims. (Cl. 219-4057) This invention relates to electrodes for applying high frequency electromagnetic energy to dielectric materials for heating purposes, and more particularly to electrodes which are suitable for the application of the high frequency energy to uneven surfaces such as concrete, rocks or like material.
In order to achieve the desired heating effect, it is necessary to apply a concentrated heating power in a relatively small volume so that a substantial temperature rise may be produced in a short time and thus produce cracks due to localized thermal expansion. In order to achieve high power concentration, i.e. field concentration, at least one of the electrodes used for applying the power must provide a small area of contact and a high voltage must be employed.
The electric field should spread out from the small-electrode so that the field intensity at a distance from the electrode is low. This requires that an electrode having a relatively large contact area be employed in conjunction with the small area of the field concentrating electrode.
A further consideration is that too high a voltage gradient across the surface of the material being heated will result in surface arcing and power losses. It is also necessary that a low resistance connection be made between the small electrode and the surface to prevent local hot spots or arcing at this electrode.
It is, therefore, an object of this invention to provide a low resistance contact for the application of high frequency energy to an uneven dielectric surface for heating of same.
In carrying out the invention, the electrode comprises a holder provided with a metal Wool of low resistance which acts as the intermediary conductor between the dielectric surface and the conductor of a high frequency energy supply source.
The invention will now be described with reference to the figures of the drawing wherein:
FIGURE 1 is an electrode system incorporating the invention which is adapted to supply radio frequency energy between a drill hole and an outside surface of the dielectric material and,
FIGURE 2 is an electrode system for applying radio frequency energy to spaced points on the surface of a dielectric material to be heated.
Referring now to FIGURE 1, a hole 10 is shown in a dielectric material 8, for instance, concrete, and high frequency electromagnetic energy is applied thereto by an electrode comprising a central conductor 1, which may be the center conductor of a coaxial cable, having a dishshaped end piece 5 with its open end facing the inner end of the drill hole. A metal wool 4, for instance copper, is squeezed between the piece 5 and the end of the drill hole and, due to its resilience, makes contact over the entire end surface of the drill hole.
A further electrode 2, in the form of an annular trough faces the outer surface or wall of the dielectric material surrounding the central conductor 1. An insulator 3, of very low dielectric loss, fixes the electrode 2 with respect to conductor 1 and insulates it therefrom. The annular trough electrode 2 is filled with a metal wool 4 which provides the contact between that electrode and the outer surface of material 8. When high frequency energy is applied between electrodes 2 and 5, the dielectric material 8 between these two electrodes is heated and the expansion cause's cracking or shattering of the material. Electrode 2 can, in itself or by additional means, prevent shattered material from flying out of the surface of the material.
In FIGURE 2, the central electrode 7 may be quite similar to electrode 5 of FIG. 1, and the annular electrode 6 may be similar to electrode 2. It is readily ap parent that an electrode system such as shown in FIG- URE 1 can be provided with a retractable central electrode to allow for variations in hole depth and also allow use of the system on a relatively flat surface. necessary that one electrode, such as 2 or 6, be annular, but this is a preferred embodiment. For instance, two electrodes, similar to the central electrode 4, 5 of the unit shown in FIGURE 1 may be employed for the two active electrodes provided, of course, that the contact area of one electrode is greater than that of the other. Two drill holes are then provided to facilitate their use. In this manner a concentrated field can be set up in the material between the two drill holes.
What is claimed is:
1. Apparatus employing high frequency electromag netic energy for heating a dielectric body, comprising an inner electrode having a resilient contact surface comprising a conductive metal wool, a spaced outer annular electrode concentric with said inner electrode and having a resilent contact surface comprising a conductive metal wool, said apparatus being positionable so that said inner electrode contact surface and said outer electrode contact surface bear against the surface of said body, and means for supplying said high frequency energy to said first and second electrodes thereby to establish an electric field in said body between said electrodes.
2. Apparatus for fracturing a brittle dielectric body by means of high frequency electromagnetic energy, comprising an inner and an outer electrode for applying said high frequency energy to said body, said outer electrode comprising an annular conductive member concentric with said inner electrode and having a resilient contact surface at one end thereof comprising a conductive metal wool, said inner electrode comprising an elongated conductive member longitudinally positioned within said outer electrode and having a dish-shaped portion at one end thereof, a conductive metal wool positioned within said dish-shaped portion so as to form a resilent area of contact with said dielectric body, and means for supplying said high frequency energy to said first and second electrodes thereby to establish an electric field in said body between said electrodes.
3. Apparatus for fracturing a brittle dielectric body by means of high frequency electromagnetic energy, comprising an inner and an outer electrode for applying said high frequency energy to said body, said outer electrode comprising an annular conductive member disposed in a plane and having a resilient contact surface at one end thereof comprising a conductive metal wool, said inner electrode comprising an elongated conductive member c0n centric with said outer electrode and radially spaced therefrom, said inner electrode extending beyond the plane of said outer electrode for insertion in a recess in said body and having a concave surface at its operative end, a conductive metal wool positioned within said concave surface portion so as to form a resilient area of contact with said dielectric body, and means for supplying said high frequency energy to said first and second electrodes thereby to establish an electric field in said body between said electrodes.
4. Apparatus for fracturing a brittle dielectric body by means of high frequency electromagnetic energy, com- It is not prising an inner and an outer electrode for applying said high frequency energy to said body, said outer electrode comprising an annular conductive member disposed in a plane and having a resilient contact surface atone end thereof comprising a conductive metal wool, said inner electrode comprising an elongated conductive member concentric with said outer electrode and radially spaced therefrom, said inner electrode extending beyond the plane of said outer electrode for insertion in a recess in said body and having a concave surface at its operative end, a conductive metal wool positioned within said concave surface portion so as to form a resilient area of contact with said dielectric body, said outer electrode having an area of contact with said dielectric body which is greater than the contact area of said inner electrode with said body, said apparatus further comprising means for longitudinally moving said inner electrode With respect to said outer electrode at right angles to the plane of contact of said outer electrode thereby to alter the dis tance said inner electrode extends beyond the plane of said outer electrode, and means for supplying said high frequency energy to said first and second electrodes thereby to establish an electric field in said body between said electrodes.
5. Apparatus employing high frequency electromagnetic energy for heating a dielectric body comprising first and second spaced apart electrodes for applying said high frequency energy to said body, said first electrode comprising a conductive member terminating in an end portion comprising a conductive metal wool in the form of a porous mass of randomly oriented metal fibers arranged to provide a low resistance resilient contact area between said first electrode and a portion of said body having a very irregular shape, said second electrode comprising a conductive member terminating in a body contacting portion having a surface contact area which is substantially larger than the contact area of said first electrode, said second electrode being arranged to contact a portion of said body spaced from said resilient contact area, and
means for supplying said high frequency energy to said in the vicinity of said second electrode.
6. Apparatus employing high frequency electromagnetic energy for heating a dielectric body, comprising an inner and an outer electrode for applying said high frequency energy to said body, said inner electrode comprising a conductive member having a resilient contact surface provided at one end thereof comprising a highly porous conductive metal wool, said outer electrode comprising an annular conductive member concentric with said inner electrode and arranged to contact -a portion of said body spaced apart from the point of contact of said inner electrode with said body, and means for supplying said high frequency energy to said first and second electrodes thereby to establish an electric field in said body between said electrodes.
7. Apparatus as described in claim 6 wherein said wool is composed of copper.
References Cited by the Examiner UNITED STATES PATENTS 2,422,525 6/1947 Brown et al 2l9-10.8 1 X 2,465,102 3/1949 Joy 21910.81 X 2,467,636 4/1949 Stoudt et al 219-58 "2,506,626 5/1950 Zottu 219--10.81 X 3,113,202 12/1963 Nolen et al. 219-92 I FOREIGN PATENTS 624,329 6/1949 Great Britain.
632,690 11/ 1949 Great Britain.
647,762 12/1950. Great Britain.
RICHARD M. WOOD, Primary Examiner.
L. H. BENDER, Assistant Examiner.
Claims (1)
1. APPARATUS EMPLOYING HIGH FREQUENCY ELECTROMAGNETIC ENERGY FOR HEATING A DIELECTRIC BODY, COMPRISING AN INNER ELECTRODE HAVING A RESILIENT CONTACT SURFACE COMPRISING A CONDUCTIVE METAL WOOL, A SPACED OUTER ANNULAR ELECTRODE CONCENTRIC WITH SAID INNER ELECTRODE AND HAVING A RESILIENT CONTACT SURFACE COMPRISING A CONDUCTIVE METAL WOOL, SAID APPARATUS BEING POSITIONABLE SO THAT SAID INNER ELECTRODE CONTACT SURFACE AND SAID OUTER ELECTRODE CONTACT SURFACE BEAR AGAINST THE SURFACE OF SAID
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA854800 | 1962-07-28 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3251975A true US3251975A (en) | 1966-05-17 |
Family
ID=4141528
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US289934A Expired - Lifetime US3251975A (en) | 1962-07-28 | 1963-06-24 | Electrode for high frequency heating |
Country Status (3)
Country | Link |
---|---|
US (1) | US3251975A (en) |
DE (1) | DE1515058A1 (en) |
GB (1) | GB1046430A (en) |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3430021A (en) * | 1965-05-05 | 1969-02-25 | Public Building & Works Uk | Methods of cracking structures and apparatus for cracking structures |
US3443051A (en) * | 1965-07-23 | 1969-05-06 | Herbert August Puschner | Apparatus for heating meterial by means of microwave device |
US3824718A (en) * | 1973-04-02 | 1974-07-23 | L Nekrasov | Excavator bucket with electromagnetic field weakening teeth |
US4900196A (en) * | 1987-11-20 | 1990-02-13 | Iit Research Institute | Confinement in porous material by driving out water and substituting sealant |
US5481092A (en) * | 1994-12-02 | 1996-01-02 | Westmeyer; Paul A. | Microwave energy generation device used to facilitate removal of concrete from a metal container |
US5586213A (en) * | 1992-02-05 | 1996-12-17 | Iit Research Institute | Ionic contact media for electrodes and soil in conduction heating |
US5879109A (en) * | 1997-02-20 | 1999-03-09 | Siemens Aktiengesellschaft | Process and apparatus for introducing an optical or electrical cable into solid ground |
US20050097850A1 (en) * | 2003-09-02 | 2005-05-12 | Rainer Hettich | Method for fastening anchoring means and device suitable for this purpose |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2422525A (en) * | 1942-07-31 | 1947-06-17 | Rca Corp | Radio-frequency electric field bonding apparatus |
US2465102A (en) * | 1943-10-04 | 1949-03-22 | Rca Corp | Radio-frequency heating apparatus |
US2467636A (en) * | 1948-07-24 | 1949-04-19 | Ames Spot Welder Co Inc | Electrode die for welding apparatus |
GB624329A (en) * | 1947-07-03 | 1949-06-02 | British Insulated Callenders | Improvements in means for heating sheet material by producing electric stress therein alternating at high frequency |
GB632690A (en) * | 1947-04-10 | 1949-11-28 | Dunlop Rubber Co | Apparatus for welding thermoplastic films |
US2506626A (en) * | 1944-05-20 | 1950-05-09 | Girdler Corp | High-frequency spot heater |
GB647762A (en) * | 1946-07-23 | 1950-12-20 | Murphy Radio Ltd | Improvements in or relating to dielectric heating apparatus |
US3113202A (en) * | 1961-08-30 | 1963-12-03 | Armour Res Found | Resistance welding method |
-
1963
- 1963-06-24 US US289934A patent/US3251975A/en not_active Expired - Lifetime
- 1963-07-24 DE DE19631515058 patent/DE1515058A1/en active Pending
- 1963-07-25 GB GB29554/63A patent/GB1046430A/en not_active Expired
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2422525A (en) * | 1942-07-31 | 1947-06-17 | Rca Corp | Radio-frequency electric field bonding apparatus |
US2465102A (en) * | 1943-10-04 | 1949-03-22 | Rca Corp | Radio-frequency heating apparatus |
US2506626A (en) * | 1944-05-20 | 1950-05-09 | Girdler Corp | High-frequency spot heater |
GB647762A (en) * | 1946-07-23 | 1950-12-20 | Murphy Radio Ltd | Improvements in or relating to dielectric heating apparatus |
GB632690A (en) * | 1947-04-10 | 1949-11-28 | Dunlop Rubber Co | Apparatus for welding thermoplastic films |
GB624329A (en) * | 1947-07-03 | 1949-06-02 | British Insulated Callenders | Improvements in means for heating sheet material by producing electric stress therein alternating at high frequency |
US2467636A (en) * | 1948-07-24 | 1949-04-19 | Ames Spot Welder Co Inc | Electrode die for welding apparatus |
US3113202A (en) * | 1961-08-30 | 1963-12-03 | Armour Res Found | Resistance welding method |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3430021A (en) * | 1965-05-05 | 1969-02-25 | Public Building & Works Uk | Methods of cracking structures and apparatus for cracking structures |
US3443051A (en) * | 1965-07-23 | 1969-05-06 | Herbert August Puschner | Apparatus for heating meterial by means of microwave device |
US3824718A (en) * | 1973-04-02 | 1974-07-23 | L Nekrasov | Excavator bucket with electromagnetic field weakening teeth |
US4900196A (en) * | 1987-11-20 | 1990-02-13 | Iit Research Institute | Confinement in porous material by driving out water and substituting sealant |
US5586213A (en) * | 1992-02-05 | 1996-12-17 | Iit Research Institute | Ionic contact media for electrodes and soil in conduction heating |
US5481092A (en) * | 1994-12-02 | 1996-01-02 | Westmeyer; Paul A. | Microwave energy generation device used to facilitate removal of concrete from a metal container |
US5879109A (en) * | 1997-02-20 | 1999-03-09 | Siemens Aktiengesellschaft | Process and apparatus for introducing an optical or electrical cable into solid ground |
US20050097850A1 (en) * | 2003-09-02 | 2005-05-12 | Rainer Hettich | Method for fastening anchoring means and device suitable for this purpose |
Also Published As
Publication number | Publication date |
---|---|
DE1515058A1 (en) | 1969-09-11 |
GB1046430A (en) | 1966-10-26 |
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