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US2756314A - High-frequency device for dielectric heating - Google Patents

High-frequency device for dielectric heating Download PDF

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Publication number
US2756314A
US2756314A US308848A US30884852A US2756314A US 2756314 A US2756314 A US 2756314A US 308848 A US308848 A US 308848A US 30884852 A US30884852 A US 30884852A US 2756314 A US2756314 A US 2756314A
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US
United States
Prior art keywords
capacitor
grid
circuit
anode
voltage divider
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
Application number
US308848A
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English (en)
Inventor
Blok Lourens
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hartford National Bank and Trust Co
Original Assignee
Hartford National Bank and Trust Co
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Hartford National Bank and Trust Co filed Critical Hartford National Bank and Trust Co
Application granted granted Critical
Publication of US2756314A publication Critical patent/US2756314A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • H03L5/02—Automatic control of voltage, current, or power of power
    • 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
    • H05B6/48—Circuits
    • H05B6/50—Circuits for monitoring or control

Definitions

  • the electron tube feedback oscillator of the high-frequency device comprises a tuned circuit which is provided between the anode and the control grid circuit and includes a coil connected in series with a load circuit-capacitor, an adjustable circuit-capacitor being placed between anode and control grid for controlling the supplied power.
  • the feedback voltage for the electron tube oscillator is taken from a variable capacitative voltage divider which is connected in parallel with the circuit capacitor and whose tapping point is connected to the tube cathode, the voltage division ratio for stabilization of the grid excitation being controlled in accordance with the grid direct current.
  • Fig. 2 is a schematic diagram of an embodiment of the high-frequency device according to the invention.
  • the voltage distribution ratio of the capacitative voltage divider 18, 19 is automatically controlled in accordance with the grid-direct current, for example, in the manner set out in the copending U. S. patent application, Serial No. 281,642, filed April 10, 1952.
  • the voltage divider capacitor 19 is variable in the present embodiment.
  • capacitor 18 instead of capacitor 19 may be variable.
  • the inductance of coil 16 was approximately 1 microhenry, the capacity variation of capacitor 15 being about 50 to 450 micro-microfarads, the capacitors 18 and 19 being 25 and 100 micro-microfarads respectively; the capacitor 20 having a capacity of 50 micro-microfarads, and the overall wiring and Zero capacity of the said capacitorsbeing approximately 120 micro-microfarads, the control range of the capacitor then being well over 1:3 corresponding to a power control of about 1:10.
  • a device 24 provided in the control grid circuit and of the type set out in the above-identified copending patent application.
  • This device comprises a magnet coil 26 connected in series with a leak resistor 25 and having a movable regulating member 27 which upon excitation of the magnet coil 26 by the grid direct current is movable against the force exerted by a spring 29 clamped unilaterally in mounting plate 28, thus varying the degree of feedback by adjustment of a capacitor 30 coupled to the regulating member.
  • a corner stay 31 Secured to a mounting plate 28 is a corner stay 31 carrying a number of adjusting screws 32 extending in a direction transversely of the spring and successively engaged by spring 29 when the regulating member moves .to the left.
  • the adjusting screws are so set that the characteristic of the spring force acting on the regulating member is a laterally inverted image of the characteristic of the magnetic attractive force exerted, the desired, as the case may be, maximum permissible excitation .of the oscillator, on the regulating member 27 relative to the axis on which the displacement of the regulating member is plotted.
  • maximum permissible excitation voltage is set up at the control grid of the oscillator throughoutthe range of powercontrol. In other words, the oscillator consistently operates under optimum operating conditions.
  • the limits of the control range of power control are mainly'deterable decrease in efiiciency of this circuit-arrangement, .notably at high capacity values of the variable capacitor 15, i. e. at low oscillator frequencies.
  • Fig. 4- is a-modification of the embodiment of the-highfrequency device of Fig. 3, corresponding elements hear- .ing thesame reference numerals.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Control Of High-Frequency Heating Circuits (AREA)
US308848A 1951-09-27 1952-09-10 High-frequency device for dielectric heating Expired - Lifetime US2756314A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
NL2756314X 1951-09-27
NL307124X 1951-09-27
NL140552X 1952-05-14

Publications (1)

Publication Number Publication Date
US2756314A true US2756314A (en) 1956-07-24

Family

ID=27617327

Family Applications (1)

Application Number Title Priority Date Filing Date
US308848A Expired - Lifetime US2756314A (en) 1951-09-27 1952-09-10 High-frequency device for dielectric heating

Country Status (2)

Country Link
US (1) US2756314A (de)
CH (1) CH307124A (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2829254A (en) * 1955-05-05 1958-04-01 Fielden Electronics Ltd Electrical measuring apparatus
US3066210A (en) * 1960-02-29 1962-11-27 Gen Electric Power oscillator

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2446032A (en) * 1944-12-09 1948-07-27 Gen Electric High-frequency generating apparatus
US2467285A (en) * 1944-07-12 1949-04-12 Rca Corp High-frequency generating system
US2473188A (en) * 1944-06-17 1949-06-14 Rca Corp Radio-frequency dielectric heater with constant heating rate control
US2485658A (en) * 1945-11-05 1949-10-25 Ellis Foster Co Radio-frequency power heating apparatus and method
US2517948A (en) * 1948-01-19 1950-08-08 Girdler Corp Oscillator control arrangement for dielectric heating systems
US2666129A (en) * 1948-03-05 1954-01-12 Nat Cylinder Gas Co System for controlling oscillator grid current
US2684433A (en) * 1952-08-05 1954-07-20 Nat Cylinder Gas Co Voltage control for high-frequency heating electrodes

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2473188A (en) * 1944-06-17 1949-06-14 Rca Corp Radio-frequency dielectric heater with constant heating rate control
US2467285A (en) * 1944-07-12 1949-04-12 Rca Corp High-frequency generating system
US2446032A (en) * 1944-12-09 1948-07-27 Gen Electric High-frequency generating apparatus
US2485658A (en) * 1945-11-05 1949-10-25 Ellis Foster Co Radio-frequency power heating apparatus and method
US2517948A (en) * 1948-01-19 1950-08-08 Girdler Corp Oscillator control arrangement for dielectric heating systems
US2666129A (en) * 1948-03-05 1954-01-12 Nat Cylinder Gas Co System for controlling oscillator grid current
US2684433A (en) * 1952-08-05 1954-07-20 Nat Cylinder Gas Co Voltage control for high-frequency heating electrodes

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2829254A (en) * 1955-05-05 1958-04-01 Fielden Electronics Ltd Electrical measuring apparatus
US3066210A (en) * 1960-02-29 1962-11-27 Gen Electric Power oscillator

Also Published As

Publication number Publication date
CH307124A (de) 1955-05-15

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