Popular in the sixties and the eighties of the high-frequency therapy (heating of body tissues in a high frequency electromagnetic field) is now almost "stalled" - first, because of the dominance of advertising of drugs, and secondly, because of the discontinuation of the RF devices. These devices ("Display", UHF 30, UHF-80) was produced with government subsidies, and market conditions have not been commercially successful. They were operational drawback - their inductive emitters give the same electric heating and capacitive.
As you know, there are two kinds of perfect radiators - electric and magnetic dipoles. The first is a two conductor, to which is applied a voltage that creates an electric field. The second is the conductor, around which a magnetic field is created. Real emitters very close to the first and far from the second. The conductors have a finite resistance, which drops the voltage creates an electric field that is strongly absorbed by living tissues. The electrical resistance loss weakens the current in the conductor and thus the magnetic field component. Therefore, to obtain magnetic heating (magnetothermal only with low impedance, high q and tuned to resonance with the oscillator frequency to within the emitters. This condition is not met in these RF devices, as they applied multiple loop circuit, and the output coil is not tuned in resonance with the generator - the presence of the patient and his movements upset the circuit.
Meanwhile, magnetoterapia has its advantages. If electric potential field in a body having a linear currents, from which the most heated skin, fat, bones and the brain that has a great resistance in a series circuit, the magnetic field creates eddy currents in the physiological fluid around the particles of insulators (e.g. cell membranes). Maximum heats the blood and cravenplan tissue. In addition, the magnetic field does not change its shape in the body and penetrates him in the air. Inflamed, swollen and tumor tissue are heated in a magnetic field more than safe to provide selective treatment. Overheating of healthy tissues impossible, because the body regulates temperature by increasing blood flow, enduring the heat. Open capillaries, most of which closed in the quiescent state. When this medication is injected into the blood, better wetting of the fabric and becomes more effective (e.g. antibiotics). Therefore, magnetoterapia used as an extra amplifier to drug therapy.
Offer the unit for magnetothermic designed for individual use. It is simple, has small size, but not suited to continuous clinical work (overheating).
Diagram of the apparatus shown in Fig. 1.
Fig. 1
Circuit elements
L1 - emitter-frame, combined with the contour generator. L2, L3-high-frequency chokes. VL1.1, VL1.2 - half generator lamp GU-29. R1, R2 is a bias resistor, R3 is a ballast resistor in the screen grid circuit. VD1 - Zener diode, extinguishing the voltage on the screen grid of the cold lamp. VD2, VD3 - rectifier diodes (any at 1000V and current 2...3A). C1, C2 - capacitor filter. T1 - filament transformer 220/12,6 In (1.25 A).
The scheme is a two-stroke generator power of 100 W at a frequency of 40 MHz. Emitter - frame diameter 20...23 see the Basis of the design is a segment of coaxial cable with the diameter of the inner insulation 4...9 mm (L1). The numbers: 1 - breaks braid, 2 - circuit ends of the braid, 3, 4 - isolated segments braid, 5, 6 - insulated ends of the conductors. When you lived such cutting of the cable remains intact and isolated. The ends 5, 6 are connected to the anodes, and lived serves as a coupling coil, the primary winding of the isolation transformer. Frame-emitter serves as a stand-alone sleeve which is closed at point 2. The power point frame - gap of the upper part (1). With this inclusion, capacity, acting between the cable conductor and the inner surface of the braid attached to the ends of the frame and serves as the capacitance of the oscillatory circuit (ideally shielded and allow for great reactive power, because the distributed capacity along the entire length of the cable and has good insulation). The magnitude of the linear capacity of a thick coaxial cable is typically 1...2 pF per centimeter, i.e. total capacity of the circuit is obtained 100...200 pF, which would be unattainable in the air condenser. On low-resistance circuit drops less voltage, so it creates less parasitic electric field. In addition, it is not affected by the output capacitance of the lamp, reducing efficiency.
Short isolated segments braid (3 and 4) serve as the plates of the feedback capacitors. Other lining - lived cable. But not only that its function. The plates still shield the ends of the cores, whereby the inductive reactance of the ends is minimal, and their equivalent diameter equal to the diameter of the braid. Thus preventing the feeder, making a loss.
The unloaded resonant circuit of the cable has a q-factor of several hundred, and loaded the patient is 50. The resonant frequency of the emitter in single-loop scheme is always the same as the frequency of the oscillator and determines, therefore, the scheme provides almost pure magnetic heating.
Scheme of cutting the cable shown in Fig.2A. Workpiece length - 95 cm At the ends of the segment lived bare (sections 1,13). On sites 2,12 removed the outer insulation and braid, internal insulation saved. Segments 3, 11 - untouched parts of the cable. They are followed by breaks braid (sections 4, 10), but the braid is here only cut from the ends of the cable and the bare ends of her blathering on parcels 5, 9 over the outer insulation. Veins braid when it come uncrossed. Braid is broken also strictly in the middle segment of the cable (section 7). Pickup braid isolated rings from the removed external insulation, and at sites 4, 7, 10 these rings are cut on a taper. On top of the rings to ruptures braid wrapped with adhesive tape. On average, the gap 7 is worn cut corrugated plastic tube 0 20 mm long 7 8...see the Ends of the tube primatyvayutsya PVC tape. The ends of the cable curl up in a frame, and seats turned braids (5, 9) are wound with bare wire and propaedeuse, as shown in Fig.26. After cutting cut, on the surface 3, 11 removed a piece of insulation for conductors from what you have! grids of the tubes.
High frequency chokes L2, L3 are performed on segments of cable without outer insulation and braid, i.e., the frame serves as the internal insulation with preserved residential. This frame is wound round the wire MGTF-0,12 or another with heat-resistant insulation, length 2.2 m. the Ends of the coil are attached rubber rings. From the end of the core is done petal for mounting, throttle.
The circuit is mounted in an elongated housing made of two metal lids with holes for ventilation and two end plugs from caprolon, plexiglass or wood. One cap pass the ends of the frame, using another power cord. The layout of the elements in the housing shown in Fig.3. The fastening elements can be carried out on screws and staples or glue gun. All current-carrying circuit diagram should be well isolated from the body!
Check the operability of the apparatus is produced by using an electric lamp with a capacity of 100...150 W (220 V) connected to two or three coils of cable (used braid) 0 20 cm At the approach of the indicator to the frame of the apparatus, the lamp should light at full intensity. The maximum illumination at a distance of 3...5 cm, corresponding to the optimal load of the generator.
It comes down to the combination of a field frame, which has the appearance of a sphere, resting on the frame, with the area of pathology. Round frame operates to a depth of about 10 cm, i.e. it is well to treat such inflammation such as bronchitis, nephritis, arthritis. For greater localization frame can be narrowed, and otolaryngology, for example, it is advantageous to bend like pokers. At the same time, keeping the body upright, near to the body of the frame is put under the chin close to her neck, and a bent portion covers the face on the nose. In such position are treated nasopharynx and ears. Relief occurs immediately after a session lasting 10 to 15 min. For other diseases the longer session - 20...30 min. In the acute form of inflammation repeat sessions after a few hours, in chronic - every day or every other day. The course of magnetothermic consists of several sessions. With the exception of fractures and arthritis, when the effective number of sessions - more than 10.
Magnetothermal can be applied in all cases, when the displayed physical therapy. A decade of experience using this method dozens of doctors for thousands of patients showed no side effects, but before applying it is recommended to consult a doctor.
Author: Yu Medinet (UB5UG), Kyiv; Publication: N. Bolshakov, rf.atnn.ru