US2765389A - Inductor for inductive h. f. heating - Google Patents
Inductor for inductive h. f. heating Download PDFInfo
- Publication number
- US2765389A US2765389A US401325A US40132553A US2765389A US 2765389 A US2765389 A US 2765389A US 401325 A US401325 A US 401325A US 40132553 A US40132553 A US 40132553A US 2765389 A US2765389 A US 2765389A
- Authority
- US
- United States
- Prior art keywords
- inductor
- heating
- conductor
- aperture
- piece
- 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
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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
- H05B6/02—Induction heating
- H05B6/36—Coil arrangements
- H05B6/362—Coil arrangements with flat coil conductors
Definitions
- This .invention relates to an inductor for inductive HF-heating comprising conductors for connection to a, high-frequency generator. If a work-piece is to be heated only at one comparatively narrow area and if use is made of an inductor of the usual type which consists of only one Winding, the work-piece is arranged in the vicinity of one conductor in such manner that the surface of the work-piece is at right angles to the plane passing through the winding. However, this involves the loss of a considerable part of the electro-magnetic field which is generated by the winding and which is not closed through the work-piece, while the coupling factor between workpiece and inductor is low.
- the inductor according to the invention is constituted by a hollow body which preferably comprises a core of material having low high-frequency losses and which exhibits an aperture, one connecting conductor being provided in the vicinity of the edge of the aperture and the other being connected at the opposite side of the aperture likewise in the vicinity of the edge and thence extending at themost at a small distance from the plane through the aperture between the lateral edges thereof until in the vicinity of the first-mentioned connecting conductor.
- the apertures which exhibit between the lateral edges of the hollow body and the last-mentioned connecting conductor serve as the working aperture.
- the inductor according to the invention is suited more particularly for superficial hardening.
- Fig. 1 is a sectional view of a known rectangular inductor.
- Fig. 2 is a sectional view of a known rectangular inductor, .if only one heating area is desired.
- Fig. 3 shows the inductor according to the invention.
- Fig. 4 is a cross-sectional view at right angles to the longitudinal direction of conductor 8 of Fig. 3.
- Figs. 5, 6 and 7 show some other practical forms of the invention.
- Fig. 8 shows the connecting conductor 5 as a conduit through which a cooling liquid flows.
- Fig. 9 is an embodiment in which the connecting conductor 8 is also a conduit through which a cooling liquid flows.
- Fig. l is a sectional view of a known rectangular inductor 1, a work-piece 2 being arranged in parallel with the plane through the inductor at a short distance therefrom.
- the field of the lines of force surrounding the two conductors is designated 3.
- the workpiece 2 will in this case be heated at the two areas indicated by 4. If only one heating area is desired, the conductors 1 would have to be approached very closely, so that the two areas 4 are coincident. This results in a material decrease in the inductance of the inductor in the unloaded state, so that the no-load current is high.
- FIG. 3 A connecting conductor 5 is connected to the edge of an aperture 6 of a hollow body 7, and another connecting conductor 8 being connected, at the opposite side, to the edge of the aperture 6 and thence extending at a small distance from the plane through the aperture 6 until in the vicinity of the conductor 5.
- the working aperture exists between lateral edges 9 and the conductor 8.
- Fig. 4 is a cross-sectional view at right angles to the longitudinal direction of conductor 3, the work-piece here being indicated by 10, the direction of movement by an arrow and the heated zone by 11.
- the fields of the lines of force surrounding the conductor 8 and the hollow body 7 are designated 12 and 13 respectively. Due to the particular shape of the hollow body 7, the field 13 is forced towards the work-piece 110, thus assisting in the heating of the work-piece in the vicinity of the boundaries of the heated zone 11. Furthermore, the inductance of the inductor in the unloaded state is sufficiently high and the coupling factor is favourable. It is evident that for a given work-piece the size and the shape of the inductor are required to be matched thereto according to the heating requirements (size of the zone to be heated, temperature, material) and the desired inductance with no-load.
- Figs. 5, 6 and 7. Some other practicable forms are shown in section in Figs. 5, 6 and 7.
- the working aperture is made even smaller, so that the lines of force surrounding the hollow body are deflected still further towards the heating area.
- the working aperture cannot be chosen unduly narrow, since otherwise the current flowing through the hollow body will not be distributed more or less evenly throughout the section thereof, but flows substantially along the two edges 9, resulting fundamentally in an approximation of the narrow coil and a decrease in inductance when the inductor is not loaded.
- the hollow body comprises a core 14, for example of ferrite material, the core projecting above the hollow body, so that the material of the core is also present between the connecting conductor 8 and the edges 9 of the hollow body. This results in the inductance of the inductor being increased and the concentrated field being brought as closely as possible to the zone to be heated.
- the inductor shown in Fig. 7, in addition to being cylindrical, may also be spherical in shape.
- the connecting conductor 5 is constituted by a conduit through which cooling liquid flows into the hollow body 7 which thus serves itself as a container.
- the cooling liquid may serve to cool the core, if available, of the inductor, as well as to chill the heated portion of the work-piece during the movement thereof (see the arrow in Fig. 4).
- FIG. 9 Another embodiment is shown in Fig. 9 in which the' connecting conductor 8 is also constituted by a conduit which serves for the discharge of cooling liquid.
- the cooling liquid is here evenly distributed through the inductor and the core (if present) through small apertures 15.
- the hollow body may have secured to it small rollers for supporting the workpiece at the correct distance above the conductor 8 and for obtaining an easy movement thereof above the inductor.
- the inductor may alternatively be used in the inversed position, so that the work-piece is provided under the inductor and is chilled more intensely by the cooling liquid flowing down.
- An inductor for inductive HF heating comprising a plurality of substantially flat conductors for connection to a high frequency generator, said inductor being closed on all said sides with the exception of said top portion which is provided with an aperture, one of said conductors being connected to said inductor at the peripheral edge of said inductor aperture, and another conductor. being connected to said inductor at an opposite edge of said inductor aperture, said other conductor extending in a different plane from said one conductor and having part thereof adjacent to the latter.
- An inductor as set forth in claim 1 further comprising an inductor winding, and the surface of the working aperture of said inductor being smaller than the crosssectional surface of said inductor winding.
- An inductor as set forth inclaim 1 further comprising a core material of low high-frequency losses in said inductor wherein said core material projects above the peripheral edge of said inductor aperture.
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- General Induction Heating (AREA)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL2765389X | 1953-01-10 | ||
NL1091257X | 1953-01-10 |
Publications (1)
Publication Number | Publication Date |
---|---|
US2765389A true US2765389A (en) | 1956-10-02 |
Family
ID=26647332
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US401325A Expired - Lifetime US2765389A (en) | 1953-01-10 | 1953-12-30 | Inductor for inductive h. f. heating |
Country Status (2)
Country | Link |
---|---|
US (1) | US2765389A (fr) |
FR (1) | FR1091257A (fr) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4340038A (en) * | 1980-12-15 | 1982-07-20 | Pacesetter Systems, Inc. | Magnetic field concentration means and method for an implanted device |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB383859A (en) * | 1931-04-06 | 1932-11-24 | Emilien Bornand | Installation for electrical welding of metals |
US2477029A (en) * | 1943-08-26 | 1949-07-26 | Ohio Crankshaft Co | Means for inductively heating flanged articles |
US2606997A (en) * | 1950-06-16 | 1952-08-12 | Asea Ab | High-frequency heating tool |
US2673922A (en) * | 1951-04-07 | 1954-03-30 | Westinghouse Electric Corp | Partial-turn inductor coil |
-
1953
- 1953-12-30 US US401325A patent/US2765389A/en not_active Expired - Lifetime
-
1954
- 1954-01-08 FR FR1091257D patent/FR1091257A/fr not_active Expired
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB383859A (en) * | 1931-04-06 | 1932-11-24 | Emilien Bornand | Installation for electrical welding of metals |
US2477029A (en) * | 1943-08-26 | 1949-07-26 | Ohio Crankshaft Co | Means for inductively heating flanged articles |
US2606997A (en) * | 1950-06-16 | 1952-08-12 | Asea Ab | High-frequency heating tool |
US2673922A (en) * | 1951-04-07 | 1954-03-30 | Westinghouse Electric Corp | Partial-turn inductor coil |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4340038A (en) * | 1980-12-15 | 1982-07-20 | Pacesetter Systems, Inc. | Magnetic field concentration means and method for an implanted device |
Also Published As
Publication number | Publication date |
---|---|
FR1091257A (fr) | 1955-04-08 |
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