RU2008947C1 - Ultrahigh frequency therapy apparatus - Google Patents

Abstract

FIELD: medical equipment, for physiotherapy. SUBSTANCE: apparatus has automatic tube generator with capacitive back coupling. Oscillating circuit of generator is formed as frame-type emitter with stub formed from a length of coaxial cable. Sheath of coaxial cable has discontinuities in the areas, where stub is separated from frame. The first and second throttles connected between tube amplifier anode and positive bus, respectively, are wound on one ends of stub and portions of cable and bare stripped sheath are disposed at other ends of stub. Sheath of the first portion is connected to second amplifier graticule and sheath of the second portion is connected to first amplifier graticule. EFFECT: increased efficiency of apparatus and enhanced reliability in operation. 2 dwg

Description

 The invention relates to medical equipment, physiotherapy, in particular to the UHF technique used for thermochemistry and thermoradiotherapy, as well as for hyperthermia of tumors. The device can be used in other areas where high-frequency heating is used.

 The known technique of UHF therapy, as well as apparatus for its implementation. As a rule, these are large and heavy devices that require a shielded room or partition to operate.

 Significantly smaller in size, easier and safer for personnel to radiate into the surrounding space the generator-emitting module.

 The study of modules showed that spurious radiation in the form of an electric field component strongly depends on the distance between conductors carrying high antiphase voltages. For example, the location of the anode chokes on the sides of the lamp unit leads to the creation of an electric dipole with a shoulder of approximately 15 cm and, accordingly, to spurious radiation, which does not destroy the metal case of the device with cooling holes.

 The prototype of this apparatus is an UHF-therapy apparatus, which is a combination of a self-oscillator and an emitter used as a generator circuit and having an inductive loop from which feedback voltage is removed.

 The prototype has the following disadvantages: the loop is too long - its length is determined by the feedback condition, - introducing energy losses, as an imperfect reactive element connected in series with the frame. In addition to lowering the efficiency, the loop reduces the resonant frequency of the frame, which may be a limitation on the applicability of the circuit; the presence of electric dipoles with a large shoulder, which increases the parasitic radiation of the apparatus (for example, a pair of spaced anode chokes), as well as the lack of structural integrity, the presence of self-made units and additional fastening elements.

 The purpose of the invention is the reduction of spurious radiation.

 The goal is achieved by removing the braid at the ends of the loop and winding the anode chokes on the open sections of the cable's inner insulation, as well as by two additional braid breaks at the ends of the loop, limiting the braid sections several centimeters long, which are connected to the grids of the generator lamps. In this case, the anodes of the lamps are connected to the central conductor of the cable at the ends or above the formed sections of the braid and chokes.

 The braid segments serve as capacitor feedback capacitor plates and are connected to the lamp grids crosswise with respect to the anode connections for the necessary phasing of the signal.

 Anode chokes in this design are spaced to a minimum distance and do not require attachment points.

 Reducing the number of parts and simplifying the design provides technological benefits.

 In FIG. 1 and 2 show the design options of the claimed device. The numbers denote: 1 - a radio tube; 2 - anode conductor; 3 - mesh conductor; 4 - a loop; 5 - a segment of a braid, 6 - a throttle; 7 - a segment of a braid; 8 - throttle; 9 - anode conductor; 10 - mesh conductor; 11 - a radio tube.

 The radio tubes 1 and 11 are located in parallel and between them are the ends of the loop 4, on which there are segments of the braid 5, 7 and the inductor 6, 8, and between the lamps 1, 11 and the conductors of the loop 4 there are grid conductors 3, 10 and anode conductors 2, 9 .

 The device (see Figs. 1 and 2) is a tube oscillator with capacitive feedback, assembled in a push-pull circuit and shown without bias elements. The anodes of the radio tubes 1, 11 are connected by conductors 2 and 9 with a residential coaxial cable, forming a frame with a loop 4, equivalent in this connection to a parallel resonant circuit. Closer to the ends of the loop 4 from the connection points 2 and 9, there are open sections of the cable’s internal insulation, which are used as frames for the chokes 6 and 8, through which the anode power is supplied. There are also short segments of the cable sheath 5 and 7, which are connected to the grids of the opposite lamps 1 and 11 by conductors 3 and 10, which ensures the supply of feedback voltage in the generator circuit: the segments 5, 7 and the cable core form coaxial capacitors with a capacity of several picofarads. The embodiment of FIG. 1 is advantageous for radio tubes 1, 11 with an anode terminal on top (for example 6P45S), and the variant in FIG. 2 - for conclusions from below (for example, GU-50). The design of the emitter loop 4 combines the elements of a circuit: anode power chokes 6, 8 and feedback capacitors 5, 7, so it is generally simpler than the prototype and more technological. The arrangement of antiphase conductors at a minimum distance localizes electric fields.

 For clinical use, the claimed device is in a metal case, from which the frame and power wires are output. The case is attached to the stand of the apparatus (tripod) using a hinge with at least three degrees of freedom. A power supply is attached to the bottom of the rack. The device does not require grounding, because it does not have an electrical housing. The lack of grounding reduces spurious radiation into space at a high frequency. The method of working with the device does not differ from the prototype: the emitter is superimposed on the pathology area of the patient and a magnetothermy session is conducted according to the accepted method.

 For the purpose of experimental verification of the claimed device, samples were made: 1) on 6P45S lamps - 4 pcs. , two in a shoulder, 2) on GU-50 lamps - also 4 pcs. Anode voltage of 900 V. A cable with fluoroplastic insulation RK-50-9-23 was used. The diameter of the frame is 24 cm, the length of the loop is 20 cm. The length of the chokes is 10 cm, the coupling capacitors are 6 cm. The gaps between the edges of the braid and the point for connecting the lamp anodes are 1 cm, the same gap is at the end of the loop. Inductors are wound with MGTF-0.12 wire, 2 m long. The wire forms a cylindrical coil, winding coil to coil. The findings are attached with rubber rings. Winding throttles in opposite directions, since the mutual induction has a positive sign. Generators are compared with the same ones made according to the prototype scheme. The difference in the length of the loop: the prototype has 30 cm. The following parameters were checked: the magnitude of the magnetic induction in the center of the frame, power (by incandescent lamp), frequency. Induction in both options was 1-1.2 G, power (full light bulbs) 250-300 watts for the claimed and 200-250 watts for the prototype. The generation frequency of the samples according to the claimed scheme was 31.5 MHz (GU-50) and 30 MHz (6P45S), and the prototype - 28 and 27 MHz, respectively.

 The spurious radiation of the devices was estimated using a C4-5 spectrum analyzer located at a distance of 5 m from the generator and receiving on an open input connector, which is equivalent to an electric dipole. The signals at the fundamental frequency and harmonics from the new devices were 10-15 dB lower than those of the prototypes. (56) Liventsev N.M., Livenson A.R. Electro-medical equipment. M.: Medicine, 1974.

 USSR author's certificate N 1690790, cl. A 61 N 1/40, 1989.

Claims (1)

 DEVICE FOR UHF-THERAPY, comprising a self-oscillator, including tube amplifiers and an oscillating circuit made in the form of a frame emitter with a loop from a segment of a coaxial cable with a braid break, cable cores are connected to the anodes of the first and second amplifiers, respectively, the first inductor connected between the anode of the first amplifier and a positive bus, a second choke, characterized in that, in order to reduce spurious radiation, the cable sheath is made with an additional gap, with the main and additional ra the rips are made at the places where the loop and the frame meet, while at the ends of the loop that are free of braiding, the first and second chokes are wound, respectively, the last of which is connected between the anode of the second amplifier and the positive bus, and at the other ends of the loop there are sections of cable with a bare braid moreover, the braid of the first section is connected to the grid of the second amplifier, the braid of the second section is connected to the grid of the first amplifier, the cable core is exposed at the ends of the loop or between the formed sections of the braid and the sections with the braid removed.

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