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US2775704A - High-frequency generators - Google Patents

High-frequency generators Download PDF

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Publication number
US2775704A
US2775704A US326656A US32665652A US2775704A US 2775704 A US2775704 A US 2775704A US 326656 A US326656 A US 326656A US 32665652 A US32665652 A US 32665652A US 2775704 A US2775704 A US 2775704A
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US
United States
Prior art keywords
circuit
anode
grid
tube
coupling
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
US326656A
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English (en)
Inventor
Martens Gunter
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 US2775704A publication Critical patent/US2775704A/en
Anticipated expiration legal-status Critical
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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/40—Applying electric fields by inductive or capacitive coupling ; Applying radio-frequency signals
    • A61N1/403—Applying electric fields by inductive or capacitive coupling ; Applying radio-frequency signals for thermotherapy, e.g. hyperthermia

Definitions

  • This invention relates to high frequency generators. More particularly, the invention relates to a high-frequency generator comprising a device for automatic control of coupling between the generator output circuit and a load circuit.
  • the generator is used more particularly for diathermy apparatus which operate with variable load.
  • the apparatus concerned frequently comprises an oscillation amplifier which is controlled by a quartz crystal. The output energy of such generators varies with the resonator resistance of the loaded anode circuit and exhibits its maximum at a determined value of this resistance, which is dependent upon the characteristic curve of the tube.
  • the output tube is in this case said to be overloaded. It however, the resonator resistance decreases, not only the high-frequency output decreases, but also the efiiciency decreases.
  • the output tube is in this case said to be underloaded. An overloaded output tube is liable to be deteriorated by the increased anode dissipation.
  • the resonator resistance of the anode circuit is substantially determined by the load which is coupled therewith.
  • the primary circuit is damped more or less and the resonator resistance varies according to the strength of coupling.
  • High-frequency generators are also used for the heating of construction material.
  • the resistance thereof may vary considerably during treatment in regard to both the dissipative component and the reactive component. This phenomenon occurs to a great extent in drying wood by means of high-frequency current. In certain cases it also occurs with diathermal treatment of patients. If the output is required to remain unvaried despite the variations in resistance, it is necessary for these variations to be compensated in some way or other.
  • the variations in dissipative resistance may be neutralized by varying the coupling between the generator output circuit and the load circuit.
  • variation in the dissipative resistance of the load may be compensated by varying the strength of the coupling between the output circuit and the load circuit and varying the reactive resistance of the load circuit by tuning means known per se.
  • voltages which are proportional to the anode current and the grid current, respectively, of an amplifying tube serve as igniting voltages for gaseous discharge tubes, the anode current of the said tubes being used for energizing in one direction or the other an electric motor which acts upon a control device by which the condition of overload or underload is obviated. If it is necessary to compensate for the variations in dissipative resistance, the electric motor acts upon the coupling between the output circuit and the load circuit in such manner that the coupling is tighter if the tube is underloaded, and looser if the tube is overloaded.
  • reference numeral 1 indicates the output tube of an oscillation amplifier which is controlled by a quartz crystal (not shown in the figure).
  • the anode of this tube is supplied from an anode-voltage source 2 by way of an oscillatory circuit comprising a capacitor 3 and an inductance coil 4.
  • the screen grid of said tube is connected to a grid-voltage source 5.
  • the oscillatory circuit 3, 4 is coupled to an oscillatory circuit which comprises a capacitor 6 and an inductance coil 7 and which forms part of the load circuit.
  • the coupling between the coils 4 and 7 is adjustable.
  • the voltage sources 2 and 5 are connected by way of resistors 8 and 9 to ground and hence to the cathode of tube 1.
  • an elecrtic motor comprising an armature It) and two field windings ll. and 12. Said windings serve to move the armature of the motor in the right-hand and in the left-hand sense of rotation, respectively.
  • the field windings 11 and 12 are each traversed by the anode current of a thyratron (13, 14 respectively).
  • the ignition grid of thyratron 13 is connected to a point 15 between voltage source 5 and resistor 9; the ignition grid of thyratron 14 being connected to a point 16 between voltage source 2 and resistor 8.
  • the cathodes of the onator resistance of the oscillatory circuit 3, 4 is at its optimum value, a voltage loss, sufficient to prevent ignition of the thyratrons, occurs across each of the resistors 8 and 9. If the tube 1 is underloaded, the point 15 becomes less negative and the thyratron 13 is ignited. If the tube 1 is overloaded, the point 16 becomes less negative and the thyratron 14 is ignited.
  • the armature of the regulating motor turns to the right or to the left according to which thyratron is ignited.
  • the movement of the armature 10 may be trans ferred to the mechanism for varying the coupling between the coils 4 and 7 by a combination of worm and worm wheel.
  • the sense of rotation is such that, if the tube 1 is underloaded, the coupling is made tighter.
  • the coupling continues to vary until the resonator resistance has approached its optimum value so closely that the tube 1 operates again in the limiting range between the positions of underload and overload.
  • Resistor 17 serves to prevent the two thyratrons from being ignited simultaneously.
  • the generator circuit of the present invention affords the advantages of avoiding reaction of variations in load upon the generator; maintaining the power supplied to the load and the efiiciency of the amplifier at a maximum, even if the resistance of the effective load during treatment varies within wide limits; and permitting the loading of the output tubes, without objection, up to the maximum permissible limit, since the output tubes are protected against excessive load.
  • a high frequency generator for supplying high frequency oscillations to a variable load comprising an amplifying stage having an input circuit and an electron discharge tube having an anode and a grid, means for applying high frequency oscillations to said input circuit, an anode circuit connected to said anode, an oscillatory output circuit connected in said anode circuit, a load circuit coupled to said output circuit, a grid circuit connected to said grid, and control means responsive to the voltage in both said anode and grid circuits to vary the coupling between said output circuit and said load circuit to maintain maximum output energy in said output circuit for all load values, said control means comprising an electric motor connected to vary said coupling, a first discharge device coupled to said motor for rotating said motor in one direction to tighten said coupling, a second discharge device coupled to said motor for rotating said motor in the opposite direction to loosen said coupling, means connecting one of said discharge devices to be responsive to the current in said anode circuit of said discharge tube, and means connecting the other of said discharge devices to be responsive to the current in said grid circuit of said
  • a high frequency generator for supplying high frequency oscillations to a variable load comprising an amplifying stage having an input circuit and an electron discharge tube having an anode and a grid, means for applying high frequency oscillations to said input circuit, an anode circuit connected to said anode, an oscillatory output circuit connected in said anode circuit, a load circuit coupled to said output circuit, a grid circuit connected to said grid, and control means responsive to the voltage in both said anode and grid circuits to vary the coupling between said output circuit and said load circuit to maintain maximum output energy in said output circuit for all load values, said control means comprising an electric motor connected to vary said coupling, a first discharge device having an anode, a cathode and a grid, coupled to said motor for rotating said motor in one direction to tighten said coupling, the grid of said first discharge device being connected in said grid circuit of said discharge tube, a second discharge device having an anode, a cathode and a grid, coupled to said motor for rotating said motor in the opposite direction to loose

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  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Radiology & Medical Imaging (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Ac-Ac Conversion (AREA)
  • Control Of Eletrric Generators (AREA)
US326656A 1952-01-18 1952-12-18 High-frequency generators Expired - Lifetime US2775704A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE310062X 1952-01-18

Publications (1)

Publication Number Publication Date
US2775704A true US2775704A (en) 1956-12-25

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Family Applications (1)

Application Number Title Priority Date Filing Date
US326656A Expired - Lifetime US2775704A (en) 1952-01-18 1952-12-18 High-frequency generators

Country Status (5)

Country Link
US (1) US2775704A (fr)
CH (1) CH310062A (fr)
FR (1) FR1069938A (fr)
GB (1) GB738777A (fr)
NL (1) NL277159A (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3505599A (en) * 1966-11-21 1970-04-07 Automatic Elect Lab A.c. power meter compensated for nonlinear rectifier
WO2008010988A1 (fr) 2006-07-19 2008-01-24 Emerson Climate Technologies, Inc. Module de protection et de diagnostic pour système de réfrigération
WO2008030572A1 (fr) 2006-09-07 2008-03-13 Emerson Climate Technologies, Inc. Module de données de compresseur
EP2530412A1 (fr) 2004-04-27 2012-12-05 Copeland Corporation Compresseur avec système de diagnostic et de protection

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2358454A (en) * 1942-04-29 1944-09-19 Rca Corp Automatic circuit tuning
US2469744A (en) * 1945-09-22 1949-05-10 Cochrane Corp Telemetering system for transmitting indications of movements
US2609510A (en) * 1945-08-06 1952-09-02 Padevco Inc Electronic heating control system

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2358454A (en) * 1942-04-29 1944-09-19 Rca Corp Automatic circuit tuning
US2609510A (en) * 1945-08-06 1952-09-02 Padevco Inc Electronic heating control system
US2469744A (en) * 1945-09-22 1949-05-10 Cochrane Corp Telemetering system for transmitting indications of movements

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3505599A (en) * 1966-11-21 1970-04-07 Automatic Elect Lab A.c. power meter compensated for nonlinear rectifier
EP2530412A1 (fr) 2004-04-27 2012-12-05 Copeland Corporation Compresseur avec système de diagnostic et de protection
WO2008010988A1 (fr) 2006-07-19 2008-01-24 Emerson Climate Technologies, Inc. Module de protection et de diagnostic pour système de réfrigération
WO2008030572A1 (fr) 2006-09-07 2008-03-13 Emerson Climate Technologies, Inc. Module de données de compresseur

Also Published As

Publication number Publication date
FR1069938A (fr) 1954-07-13
NL277159A (fr)
GB738777A (en) 1955-10-19
CH310062A (de) 1955-09-30

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