US2751502A - High-frequency heating generator - Google Patents
High-frequency heating generator Download PDFInfo
- Publication number
- US2751502A US2751502A US303195A US30319552A US2751502A US 2751502 A US2751502 A US 2751502A US 303195 A US303195 A US 303195A US 30319552 A US30319552 A US 30319552A US 2751502 A US2751502 A US 2751502A
- Authority
- US
- United States
- Prior art keywords
- coil
- generator
- water
- anode
- cooling water
- 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
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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
- H05B6/04—Sources of current
Definitions
- This invention relates to high-frequency heating generators comprising an electronic tube oscillator having a water-cooled primary or tank coil which is closely surrounded by a secondary or coupling coil in the form of a circularly bent metal. strip.
- the water cooling of the tank coil is required to enable the heat produced by the high-frequency losses in the coil to be conducted away.
- the secondary coil has only one turn and is connected to the (external) heating coil, in the field of which the material to be heated is arranged.
- the coupling between the primary and secondary coils should be comparatively tight and hence the secondary is required to surround the tank coil, for example, with a 10 w. generator the intermediate spacing is about 7 mm.
- a high-frequency heating generator comprising a discharge tube oscillator having a water-cooled tank coil which is closely surrounded by a secondary coil in the form of a circularly bent metal strip, is characterized in that the supply pipe for cooling water for cooling the coil contains an electrically controllable valve and control means are provided to permit flow of cooling water only when the generator is in use, but does not act to any appreciable extent on the supply of the cooling water to the anode of the oscillating tube.
- valvecontrol electro-magnet in a circuit in which the magnet winding is connected into circuit simultaneously with the anode supply transformer of the generator.
- cooling water flows only when the anode supply voltage of the oscillating tube is connected into circuit and does not flow when this voltage is cut oil, the coil being thus prevented from becoming cooled to a temperature lower than the temperature of the atmosphere.
- Fig. l is a perspective view of the essential parts of an embodiment of the invention.
- Fig. 2 is a sectional detail view thereof.
- Fig. 1 shows a water-cooled coil system of a highfrequency heating generator comprising a primary coil 1 Wound from copper tubing and a copper strip 3 which, bent to form a cylindrical shell closed but for a small slit, is arranged to surround the coil co-axially and constitutes a secondary coil.
- the copper strip is bent outwardly at right angles thereto and the two ends 3 and 3" of the strip are arranged spatially parallel to one another with a very small intermediate space of, say, one millimeter, are substan tially radial to the circularly bent part and constitute connections to a heating coil (not shown) which may be screwed to two copper connecting blocks 5 and 7 secured to the ends 3 and 3", respectively.
- the coil 1 is wound on a support comprising three radially arranged strips 9 of low-loss insulating material which each has one end secured to a vertical metal wall which forms part of a transportable frame 11.
- the coil 1 can be moved into and out of the secondary coil 3 to vary the coupling and thus control the output energy.
- T he coil 1 has cooling water fed to it through a flexible tube 13.
- the cooling water passes through the coil 1, a second rubber tube 15, a connecting pipe 17, flexible tubes 19, 21 and 23, and hence flows through the con necting blocks 5 and 7, and passes finally through a discharge pipe 25.
- the maximum coupling between the coils 1 and 3 is required to be very tight in order that in practice it may be possible at any load to feed the maximum energy to the heating coil.
- the diiierence in spacing between the primary and secondary coils is therefore small. With a 10 kw. generator, the spacing is about 1 cm., the primary coil having a diameter of about 30 cm. Due to divergence from exact co-axial arrangement of the coils 1 and 3 which can only with difiiculty be avoided, a minimum spacing of about 7 mm. may be assumed. This is sufficient to avoid arcing between the coils under normal conditions.
- the operation of the generator is continuously interrupted temporarily by switching off the anode supply voltage of the thermionic tube, the other supply potentials and auxiliary potentials remaining connected. If cooling water were permitted to continue to flow when no heating of the core 1 by high-frequency losses in the coil 1 was taking place, the coil might be cooled by the cooling waterthe temperature of which may be 12 C.-to below the dew point of the surrounding atmosphere with the result that vapour would condense on the coil and drops suspended from the coil 1 would be liable to bring about arcing between the coils l and 3 on the anode voltage again being supplied to the discharge tube.
- the water supply pipe contains an electrically controllable valve 29 which permits flow of cooling water only when the generator is in use but does not act to any appreciable extent on the cooling circuit for the anodes of the oscillating tubes.
- the valve shown in Fig. 2 is of known construction and comprises a stud 31 having a conical end which in its normal position closes an entry-port 33, thus shutting oil? the flow of cooling water.
- the valve control device comprises an electro-magnet 35 the armature 37 of which, on energization of the magnet, raises the stud 31 against the pressure of a spring 39.
- the magnet 35 may be included in an auxiliary circuit which is established and broken by a contact of a relay 43 by which anode-voltage supply transformer 41 is controlled.
- the flow of cooling water through the coil 1 is consequently interrupted when the generator is not in use; the water that may be available within the coil is always warm enough to avoid condensation.
- the device described above is not efiective if the oscillator stops oscillating for a short period due to a fault or to excessive load and thereafter again starts to oscillate, in which case condensation of vapour on the coil and arcing are therefore liable to occur. If desired, this may also be taken into account, for example, by energizing the magnet 35 with the use of a direct current obtained by rectification of a small part of the high-frequency output current of the tube or with the use of a current controlled by such rectified current With the aid of a relay or relays.
- a high-frequency generator comprising; a discharge tube oscillator provided with a water-cooled anode, a water-cooled primary coil operatively connected to said oscillatory, a secondary coil in the form of a circularly bent metal strip surrounding said primary coil with relatively small spacing therebetween, a water supply pipe for cooling the primary coil, and an electrically controllable valve in said water supply pipe including an armature, a source of electrical current, an electromagnet which upon magnetization operates said valve to permit the flow of cooling water only when said generator and said electromagnet have said current applied thereto but does not interrupt the continual supply of water to the anode of said oscillator.
- a high-frequency generator comprising; a discharge tube oscillator provided with a Water-cooled anode, a water-cooled primary coil operatively connected to said oscillator, a secondary coil in the form of a circularly bent metal strip surrounding said primary coil with relatively small spacing therebetween, said circularly bent metal strip having two elongated ends extending radially from said metal strip and transverse to the axis thereof, said two ends being parallel-spaced and each having a connecting block secured thereto, a water supply pipe for cooling the primary coil, and an electrically controllable valve in said water supply pipe including an armature, a source of electrical current, and electromagnet which upon magnetization operates said valve to permit the flow of cooling water only when said generator and said electromagnet have said current applied thereto but does not interrupt the continual supply of water to the anode of said oscillator.
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- General Induction Heating (AREA)
- Water Treatment By Electricity Or Magnetism (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL305864X | 1951-09-26 |
Publications (1)
Publication Number | Publication Date |
---|---|
US2751502A true US2751502A (en) | 1956-06-19 |
Family
ID=19783485
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US303195A Expired - Lifetime US2751502A (en) | 1951-09-26 | 1952-08-07 | High-frequency heating generator |
Country Status (6)
Country | Link |
---|---|
US (1) | US2751502A (sk) |
BE (1) | BE514401A (sk) |
CH (1) | CH305864A (sk) |
DE (1) | DE922007C (sk) |
FR (1) | FR1063611A (sk) |
GB (1) | GB708796A (sk) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3535809A (en) * | 1967-11-03 | 1970-10-27 | Hoffmann Werke Oswald | Firing equipment for simulating gunfire |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1987458A (en) * | 1928-11-16 | 1935-01-08 | Youngstown Sheet And Tube Co | Induction heater |
US2138181A (en) * | 1933-01-14 | 1938-11-29 | Rca Corp | Short wave signaling |
US2403969A (en) * | 1943-03-10 | 1946-07-16 | Jacob H Fledel-Beck | Split induction coil furnace |
US2404404A (en) * | 1943-05-15 | 1946-07-23 | Rca Corp | High-frequency apparatus |
US2455822A (en) * | 1944-06-07 | 1948-12-07 | Sunbeam Corp | Apparatus for heat-treating metal parts |
US2672544A (en) * | 1948-11-30 | 1954-03-16 | Marocaine Tech Et Commerciale | Apparatus for welding by means of electromagnetic induction heating |
-
0
- BE BE514401D patent/BE514401A/xx unknown
-
1952
- 1952-08-07 US US303195A patent/US2751502A/en not_active Expired - Lifetime
- 1952-09-21 DE DEN6108A patent/DE922007C/de not_active Expired
- 1952-09-23 GB GB23835/52A patent/GB708796A/en not_active Expired
- 1952-09-24 FR FR1063611D patent/FR1063611A/fr not_active Expired
- 1952-09-24 CH CH305864D patent/CH305864A/de unknown
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1987458A (en) * | 1928-11-16 | 1935-01-08 | Youngstown Sheet And Tube Co | Induction heater |
US2138181A (en) * | 1933-01-14 | 1938-11-29 | Rca Corp | Short wave signaling |
US2403969A (en) * | 1943-03-10 | 1946-07-16 | Jacob H Fledel-Beck | Split induction coil furnace |
US2404404A (en) * | 1943-05-15 | 1946-07-23 | Rca Corp | High-frequency apparatus |
US2455822A (en) * | 1944-06-07 | 1948-12-07 | Sunbeam Corp | Apparatus for heat-treating metal parts |
US2672544A (en) * | 1948-11-30 | 1954-03-16 | Marocaine Tech Et Commerciale | Apparatus for welding by means of electromagnetic induction heating |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3535809A (en) * | 1967-11-03 | 1970-10-27 | Hoffmann Werke Oswald | Firing equipment for simulating gunfire |
Also Published As
Publication number | Publication date |
---|---|
GB708796A (en) | 1954-05-12 |
FR1063611A (fr) | 1954-05-05 |
DE922007C (de) | 1955-01-07 |
CH305864A (de) | 1955-03-15 |
BE514401A (sk) |
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