US2589027A - High-frequency furnace - Google Patents
High-frequency furnace Download PDFInfo
- Publication number
- US2589027A US2589027A US706237A US70623746A US2589027A US 2589027 A US2589027 A US 2589027A US 706237 A US706237 A US 706237A US 70623746 A US70623746 A US 70623746A US 2589027 A US2589027 A US 2589027A
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- US
- United States
- Prior art keywords
- grid
- frequency
- anode
- circuit
- cathode
- 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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-
- 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
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION, OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
- H03L5/00—Automatic control of voltage, current, or power
Definitions
- This invention relates to a high-frequency furnace which consists of a tube oscillator, where the article to be heated is placed within the generator coil, more particularly to a high-frequency furnace for hardening purposes.
- the high-frequency voltage increases very strongly owing to the fact that the quality of the generator circuit has increased.
- this drawback is met by interposing a diode in the grid circuit of an oscillator tube of a high-frequency furnace, the cathode of which is connected to the grid and the saturation current of which is equal to the maximum permissible grid current.
- the diode transmits the grid current without undue voltage losses.
- the grid current cannot surpass the maximum value despite an increase in high-frequency voltage.
- the grid receives a strongly negative voltage, so that the anode current and consequently also the high-frequency voltage of the circuit do not exceed undue values.
- the oscillator tube of a highfrequency furnace is denoted by I, the cathode by 2, the grid by 3 and the anode by ll.
- the generator circuit consists of a condenser and a coil 5.
- the grid is connected to the generator circuit through a diode l, which is bridged by a condenser 3.
- the grid is connected to the cathode of the diode.
- the cathode of the triode f is fed from the low tension mains through the intermediary of a transformer iQ, whereas the anode is supplied with low-frequency alternating current through the terminals i3.
- Within the generator coil 6 is placed a steel shaft Si which has to be hardened, to which end it must be kept in the coil for two seconds. When the shaft li is inside the coil (i, the quality of the circuit is poor and the high-frequency voltage keeps within the permissible limits.
- the quality of the circuit increases.
- the high-frequency voltage increases and consequently also the grid current, but only to the saturation current of the diode l.
- the negative grid voltage increases, so that the anode current and consequently the high-frequency voltage can no longer increase.
- a high-frequency oscillator comprising an electron discharge tube having a cathode, a grid i an anode, a resonant circuit coupled between said anode and said grid, and a diode discharge device having a cathode and an anode, said device being interposed between said grid and circuit with the cathode of said device con...oted to said grid and the anode thereoic ected to one end of said circuit, said device characterized by a value of saturation current which corresponds to the maximum permissibl grid current of said tube.
- said device being characterized ⁇ by a value of" saturation current which corresponds ⁇ tot. the maximum permissible grid current of-'saidtube.
- a high-frequency 'oscillator nforV induction heating comprising an electron discharge tube having a cathode, a grid and an anode, a resonant circuit constituted by an induction heating coil in parallel with a condenser, one end of said circuitzbeingiconnectedto the# anode ofzsaidftube, al. diode: discharge device having a/ cathode"A and:
- anr anode the' cathode: ofVv said,k device being connectedto theigridrof said'tube, the anode of'said device-being connected. to the otherY end of saidr circuit; al coupling capacitorishunted across said device; ⁇ andimeanslto applyfa ⁇ low-frequency exi-- 4 ergiaingv potential between the cathode of said tube and a tap yon said coil, said device being characterized by a value of saturation current which corresponds to the maximum permissible 'grid current of said tube.
Description
March 11, 1952 K, PQSTHUMUS 2,589,027
HIGH-FREQUENCY FURNACE Filed Oct. 28, 1946 ATTORNEY Patented Mar. l1, 195552 UNITED STATES PATENT OFFICE Application October 28, i946, Serial No. 765,237
En the Netherlands duly 24, 1945 Section 1, Public Law 690, August S, 1946 Patent expires July 24, 1955 3 Claims.
This invention relates to a high-frequency furnace which consists of a tube oscillator, where the article to be heated is placed within the generator coil, more particularly to a high-frequency furnace for hardening purposes.
When, in a high-frequency furnace referred to, the article to be heated is taken out of the generator coil, the high-frequency voltage increases very strongly owing to the fact that the quality of the generator circuit has increased.
strong. If the articles to be heated have to stay for a comparatively long time in the coil this readjustment does not constitute a series drawback in general. Of course, control members must be available. With furnaces for hardening purposes, however, the article to be treated is kept in the coil for a very short time, usually for a few seconds only. In this case, it is consequently very objectionable to control the voltage or, as the case may be, to out it in and out or to control either any of the circuit elements or the coupling, because this control then takes more time than the thermal treatment itself, thus working very ineffectively.
By the present invention this drawback is met by interposing a diode in the grid circuit of an oscillator tube of a high-frequency furnace, the cathode of which is connected to the grid and the saturation current of which is equal to the maximum permissible grid current.
Ii there is an article in the coil, the diode transmits the grid current without undue voltage losses. When the article is withdrawn yfrom the coil the grid current cannot surpass the maximum value despite an increase in high-frequency voltage. The grid receives a strongly negative voltage, so that the anode current and consequently also the high-frequency voltage of the circuit do not exceed undue values. The advantage over all other controls consists in that this method is entirely devoid of inertia and in that no additional control members need be available, it being only necessary that the diode in the grid circuit should be capable of withstanding a proper voltage.
True, it is alreadyvknown with transmitters to insert a diode in the grid circuit of an oscillator tube to prevent the grid current from reversing its sign or from acquiring an unduly high value, but in these arrangements the dio-cle is only started up by disturbances which would cause a reversal or abnormal increase of the grid current and not, as with the aforesaid high-freuency furnace, by changing the load at any one une.
In order that the invention may be clearly understood and readily carried into effect, it will now be described more fully with reference to the accompanying drawing, given by way of example, which represents a high-frequency oscillator for a high-frequency furnace according to the invention.
In the drawing the oscillator tube of a highfrequency furnace is denoted by I, the cathode by 2, the grid by 3 and the anode by ll.
The generator circuit consists of a condenser and a coil 5. The grid is connected to the generator circuit through a diode l, which is bridged by a condenser 3. The grid is connected to the cathode of the diode. The cathode of the triode f is fed from the low tension mains through the intermediary of a transformer iQ, whereas the anode is supplied with low-frequency alternating current through the terminals i3. Within the generator coil 6 is placed a steel shaft Si which has to be hardened, to which end it must be kept in the coil for two seconds. When the shaft li is inside the coil (i, the quality of the circuit is poor and the high-frequency voltage keeps within the permissible limits. If, however, the shaft is withdrawn, the quality of the circuit increases. The high-frequency voltage increases and consequently also the grid current, but only to the saturation current of the diode l. The negative grid voltage increases, so that the anode current and consequently the high-frequency voltage can no longer increase.
What I claim is:
l. A high-frequency oscillator comprising an electron discharge tube having a cathode, a grid i an anode, a resonant circuit coupled between said anode and said grid, and a diode discharge device having a cathode and an anode, said device being interposed between said grid and circuit with the cathode of said device con...oted to said grid and the anode thereoic ected to one end of said circuit, said device characterized by a value of saturation current which corresponds to the maximum permissibl grid current of said tube.
2, .Zi high-frequency oscillator comprising an being connected in parallel with capacitor'with the cathode of said device being connected to the grid of said tube and the anode of saidA device be'- ing connected to said other end of saidcircuit.
said device being characterized `by a value of" saturation current which corresponds` tot. the maximum permissible grid current of-'saidtube.
3. A high-frequency 'oscillator nforV induction heating comprising an electron discharge tube having a cathode, a grid and an anode, a resonant circuit constituted by an induction heating coil in parallel with a condenser, one end of said circuitzbeingiconnectedto the# anode ofzsaidftube, al. diode: discharge device having a/ cathode"A and:
anr anode;.the' cathode: ofVv said,k device being connectedto theigridrof said'tube, the anode of'said device-being connected. to the otherY end of saidr circuit; al coupling capacitorishunted across said device;` andimeanslto applyfa` low-frequency exi-- 4 ergiaingv potential between the cathode of said tube and a tap yon said coil, said device being characterized by a value of saturation current which corresponds to the maximum permissible 'grid current of said tube.-
KLAAS POSTHUMUS.
REFERENCES CITED The following references are of record in the le of this patent.:
UNITEDv STATES PATENTS Number Name Date 1,551,822 Grant Sept. 1, 1925 1,839,481 Holst et al Jan. 5, 1932 2,113g956. Ebbighausen Apr. 5, 1938 2;175,694 Jones Oct. 10, 1939 2,304,958u Rfouy Dec. 15, 1942 2,320,876 y Marby June 1, 1943 2,351,4391 Livingston June.13, 1944 2,391,085.v Crandell Dec. 18, 1945. 2,408,229 Roberds. Sept. 24, 19,461. 2,414,141 Denneenxet a1. ,Jan.v 14, .1947 2,415,799 Reifeltetfal. Feb.4 .1,1, ,194.7 2,420,857 Brown May 201947 2,450,623- Anderson: Oct. 5,1948
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL807111X | 1945-07-24 | ||
| NL2589027X | 1945-07-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2589027A true US2589027A (en) | 1952-03-11 |
Family
ID=26645663
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US706237A Expired - Lifetime US2589027A (en) | 1945-07-24 | 1946-10-28 | High-frequency furnace |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US2589027A (en) |
| DE (1) | DE807111C (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE972395C (en) * | 1952-08-31 | 1959-07-16 | Siemens Ag | High frequency generator with feedback |
| DE1015659B (en) * | 1953-02-23 | 1957-09-12 | Licentia Gmbh | Plant for enamelling sheet metal |
| DE1025061B (en) * | 1954-09-10 | 1958-02-27 | Siemens Ag | Device for regulating the grid modulation in high-frequency tube generators |
Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1551822A (en) * | 1924-12-22 | 1925-09-01 | Electrical Improvements Ltd | Electric heating apparatus |
| US1839481A (en) * | 1926-04-09 | 1932-01-05 | Rca Corp | Circuit arbangement for generating electric oscillations |
| US2113956A (en) * | 1935-03-27 | 1938-04-12 | Ball Brothers Co | Method and apparatus for feeding molten glass |
| US2175694A (en) * | 1938-07-30 | 1939-10-10 | Rca Corp | Oscillator |
| US2304958A (en) * | 1940-11-25 | 1942-12-15 | Rouy Auguste Louis Mar Antoine | Heating of dielectric materials |
| US2320876A (en) * | 1941-12-30 | 1943-06-01 | Westinghouse Electric & Mfg Co | Automatic amplitude control for oscillator circuits |
| US2351439A (en) * | 1941-05-02 | 1944-06-13 | Gen Electric | Electric valve oscillator |
| US2391085A (en) * | 1943-09-28 | 1945-12-18 | Compo Shoe Machinery Corp | Thermionic oscillator |
| US2408229A (en) * | 1943-04-30 | 1946-09-24 | Rca Corp | Electrical heating apparatus |
| US2414141A (en) * | 1942-11-12 | 1947-01-14 | Ohio Crankshaft Co | Controlling inductive heating |
| US2415799A (en) * | 1945-03-09 | 1947-02-11 | Stevens Arnold Company Inc | Automatic means for controlling the power fed to an oscillator load |
| US2420857A (en) * | 1944-12-09 | 1947-05-20 | Gen Electric | Electric discharge device oscillator with nonlinear grid leak resistor |
| US2450623A (en) * | 1944-10-20 | 1948-10-05 | Gen Electric | High-frequency induction heating system |
-
1946
- 1946-10-28 US US706237A patent/US2589027A/en not_active Expired - Lifetime
-
1948
- 1948-11-26 DE DEP22665D patent/DE807111C/en not_active Expired
Patent Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1551822A (en) * | 1924-12-22 | 1925-09-01 | Electrical Improvements Ltd | Electric heating apparatus |
| US1839481A (en) * | 1926-04-09 | 1932-01-05 | Rca Corp | Circuit arbangement for generating electric oscillations |
| US2113956A (en) * | 1935-03-27 | 1938-04-12 | Ball Brothers Co | Method and apparatus for feeding molten glass |
| US2175694A (en) * | 1938-07-30 | 1939-10-10 | Rca Corp | Oscillator |
| US2304958A (en) * | 1940-11-25 | 1942-12-15 | Rouy Auguste Louis Mar Antoine | Heating of dielectric materials |
| US2351439A (en) * | 1941-05-02 | 1944-06-13 | Gen Electric | Electric valve oscillator |
| US2320876A (en) * | 1941-12-30 | 1943-06-01 | Westinghouse Electric & Mfg Co | Automatic amplitude control for oscillator circuits |
| US2414141A (en) * | 1942-11-12 | 1947-01-14 | Ohio Crankshaft Co | Controlling inductive heating |
| US2408229A (en) * | 1943-04-30 | 1946-09-24 | Rca Corp | Electrical heating apparatus |
| US2391085A (en) * | 1943-09-28 | 1945-12-18 | Compo Shoe Machinery Corp | Thermionic oscillator |
| US2450623A (en) * | 1944-10-20 | 1948-10-05 | Gen Electric | High-frequency induction heating system |
| US2420857A (en) * | 1944-12-09 | 1947-05-20 | Gen Electric | Electric discharge device oscillator with nonlinear grid leak resistor |
| US2415799A (en) * | 1945-03-09 | 1947-02-11 | Stevens Arnold Company Inc | Automatic means for controlling the power fed to an oscillator load |
Also Published As
| Publication number | Publication date |
|---|---|
| DE807111C (en) | 1951-06-25 |
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