Apparatus for magnetothermy. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / Electronics in medicine

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Radioamateur published an apparatus for magnetothermy - therapeutic heating of the body in a high-frequency magnetic field [1]. I offer a more powerful device suitable for the therapy of internal organs. Let me remind you that only blood is heated in a magnetic HF field - like a magnetodielectric with losses (a person has 5 kg of iron for 1 liters of blood). At the same time, the body, as a large self-regulating system, strengthens and expands the blood flow as much as necessary to stabilize the body temperature. But increased blood circulation (microcirculation) has a strong healing effect. Magnetothermia successfully treats most inflammations (for example, colds). And in combination with drugs and the method of thermochemotherapy, it is truly universal.

The new device is a two-tube push-pull generator with a power of up to 150 W at a frequency of 40 MHz. The scheme of the device is shown in Fig.1. The generator is combined with a frame emitter, which simultaneously serves as an oscillatory circuit of the generator.

At a given power in the center of the frame, the magnetic field strength is tens of amperes per meter. The capacitor of the oscillatory circuit is the internal capacitance of the cable segment forming the frame. With the inclusion shown, this capacitance is applied to the ends of the inductor. Positive feedback is fed to the control grids of the lamps through capacitors, which are small isolated pieces of braid at the ends of the cable segment. The same segments of the braid reduce the inductance of the frame leads, increasing their effective diameter. The generator is powered by a mains voltage rectifier 220 V with doubling. 600 V is supplied to the anodes of the lamps, about 200 V to the screen grids, taking into account the voltage suppression at the zener diode and ballast resistor.

Structural elements of the scheme. High-frequency chokes L3, L4 are 2 m of MGTF-0,14 wire, wound coil to coil on a piece of coaxial cable with a removed braid (that is, its internal insulation and core are preserved) with a diameter of 9 mm or on a special frame. The ends of the conductor are fixed with rubber rings cut from a tube with a diameter of 4 ... 5 mm. On one side of the cable segment, the core is exposed by 3 ... 4 cm and wrapped in an eye for attaching the throttle to the chassis.

The communication loop L2 is oval in shape, with an area of ​​​​several square centimeters from a well-insulated wire (MGTF). Frame L1 is made from a piece of coaxial cable PK50-9-23. If it is not available, a replacement is possible (as preferred): PK50-4-21, PK50-2-21, PK50-7-11 or PK50-4-11. In any case, it is desirable to take a cable that is heat-resistant and elastic, retaining its shape when bent. When using a cable with outer fiberglass insulation, a rubber tube is put on top. The length of the cable segment is 1m. The scheme of its cutting is shown in Fig.2.

Ris.2

The numbers are:

-1,7 - the central core is bare at a length of 5 ... 8 mm, internal insulation - at a length of 10 mm;

- 2, 6 - intact sections of the cable 45 mm long;

- 3, 5 - breaks in the braid at a length of 10 ... 12 mm, internal insulation is preserved. The ends of the braid cut (using an awl and nail scissors) are turned onto the cable surface towards the middle of the segment;

- 4 - rupture of the braid on a length of 15 mm strictly in the middle of the cable segment.

All places of braid breaks are wrapped with PTFE tape to the level of external insulation. A piece of rubber or corrugated acrylic tube (sanitary) with a diameter of 20 mm is put on top, the ends of which are melted with thermoplastic. The places of braid breaks can also be repaired with segments of the outer insulation of the polyethylene cable, wrapping them with adhesive tape. The cable segment is folded into a round frame, the turned ends of the braid are wrapped with two or three turns of bare wire and soldered, forming a jumper. The distance between the ends of the cable in this place is 5...8 mm.

Cutting sequence: break and isolate section 4, then pass the ends of the cable section through the holes in the lining and the front cover of the case, and then make the rest of the cutting.

The device is mounted in two housings 90x150x160 mm in size made of high-impact polystyrene. The generator is placed in one case, the power supply is placed in the other. The hulls are glued with blind sides ("Moment" glue). The double wall forms a chassis on which all elements of the circuit are attached - by pressing the leads and mounting collars from a wire with a diameter of 1 mm into plastic with a heated soldering iron. The location of the elements in the generator block is shown in Fig.3.

Ris.3

First, pieces of bare tinned wire with a diameter of 1 mm and a length of 20 ... 30 mm are soldered to the contacts of the lamp panels. The end of the wire is inserted into the "eye" of the socket, bent and crimped, and the conclusions of the circuit elements and wires are soldered to these conductors. The cathode terminals of the lamps are connected by a cable braid bus, which is shown in the figure. The length of the anode connecting conductors is longer; heat-resistant insulation is put on them. For frame L2, holes are drilled in the trim and cover directly next to the frame cable L1. Outside, the conductor L2 is preferably melted with thermoplastic. The lamps are fixed with a stud and a nut, which abuts against the front cover. The distance from the cover to the lamps is 25 mm. To blow the lamps, a fan is used, connected to the power wires through a resistor (to reduce the hum). You can use a 12V fan, powered by the filament voltage of the lamps through a rectifier (diode, 20 uFx15 V capacitor and 10 Ohm resistor). The inner surface of the generator block is covered with foil to reflect heat from the plastic. Installation of the power supply - arbitrary, there is plenty of space in the case. Transformer T1 is attached to the mount of the device on a tripod through the cover. Lamp panels can be made by yourself. The sockets are made of bare wire with a diameter of 1 mm. On a drill with a diameter of 2,2 ... 2,3 mm, a cylindrical spiral 8 ... 9 mm high is wound from it, on which a toroidal winding is applied - 10 ... 12 turns of bare steel wire with a diameter of 0,3 ... 0,35, 1,5 mm (you can take nichrome). The ends of the spiral are passed through the holes in the fiberglass or getinax board 2 ... XNUMX mm thick and twisted on the other side of the board. Holes for the ends of the sockets are located radially in a circle (as the lamp pins are located).

The general view of the device is shown in Fig.4.

Ris.4

The numbers indicate: 1 - overlay, 2 - generator unit, 3 - power supply, 4 - attachment to a tripod, 5 - screw with a handle, 6 - power cable, 7 - tripod stand, 8 - attachment point for tripod elements, 9 - legs tripod.

Overlay 1 (20 ... 30 mm thick), attachment points 4 and 8 are made of caprolon, plexiglass or solid wood.

Tripod elements 7, 9 - fiberglass or aluminum tubes (ski poles). You can use wooden handles from garden tools.

The effective shape of the emitter-frame field has the form of a somewhat flattened sphere resting on the frame. For treatment, this "sphere" must be combined with a diseased organ. For example, in the treatment of arthritis, the frame is put on a limb or applied to a sore spot on the side. For all inflammations in otolaryngology, it is advantageous to bend the frame in the plane in half at an angle of 90 ° and attach the bent part to the neck, and keep the part closest to the body at the level of the nose. At the same time, the places of bends approach the ears, and in the latter one feels warm. In this way, inflammation of the nasopharynx is treated - a place accessible only to invasive methods. For the treatment of bronchitis, pneumonia, hepatitis and other inflammations of the internal organs, the frame should be placed flat on the surface of the body against this organ. The indicator of the device operation (field indicator), in addition to the LEDs, is an incandescent lamp (6,3 V) connected to a coil with a diameter of 3 ... 4 cm (a neon lamp does not light up in a magnetic field). When heating a massive part of the body (chest, abdomen), a field indicator is placed on the surface and the frame of the device is brought to a distance where the light bulb glows most brightly (usually 1 ... 2 cm). Foam pads are used to fix the frame. When the back is heated (osteochondrosis), it is convenient to turn the device upside down with the power supply - then the body does not interfere with the procedure. The duration of the session is from 5 to 30 minutes (for the head - 10). Acute neuritis (sciatica) is well treated with sessions of 5-7 minutes in half an hour. Chronic inflammation - sessions once a day or every other day. Usually 3-10 sessions are enough. A decade of clinical experience with magnetothermia has not revealed any harmful side effects, and all inflammations ending in "-itis" are treatable. However, you need a diagnosis that the doctor will establish.

The device radiates very little into the surrounding space and fits perfectly into the set background level.

The author suggests the question: why is the generator not on transistors? The answer is that transistors are more expensive (the right one costs tens of dollars). In addition, the lamp allows a case temperature of 200°C, and the transistor - 60°C, i.e. you need a good heatsink. Still no gain in volume. Finally, the gain of the lamp is 40 dB, while the transistor (good) is only 15 dB.

Literature

1. Radio amateur, 1999, N6, p.31.

Author: Y. Medinets, Kiev; Publication: N. Bolshakov, rf.atnn.ru

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