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ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING Hydroionizer. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Electronics in medicine The healing properties of the air of forests, mountains, alpine meadows, the sea have long been known to mankind. Even the ancient Greek physician Hippocrates noticed that mountain and sea air have a beneficial effect on a person, healing from many diseases. The nature of the beneficial effects of such air was discovered by scientists I. Elster and G. Geitel. They found that ions of air gases - air ions, as A. Chizhevsky later called them, have healing properties. Air ionization occurs under the influence of radioactive radiation from soil and water, ultraviolet radiation from the Sun, cosmic rays, electrical discharges in the atmosphere (lightning, discharges on mountain tops, needles of coniferous trees, etc.), as well as when water is crushed and sprayed during a storm , rain, near waterfalls. Air ions have a negative or positive charge. Negative air ions are represented by oxygen, which easily captures free electrons from the outside. Positive air ions - carbon dioxide and nitrogen, if they lose one of the electrons. Negative and positive air ions affect the human body and animals differently. Chizhevsky in his experiments found out that negative air ions prolong life, and positive ones, on the contrary, shorten life. But the air, devoid of all air ions, had an even more detrimental effect on animals. Air with an excess of oxygen air ions stabilizes blood pressure, makes breathing deeper, increases appetite and improves digestion. Air ions affect the physicochemical properties of blood: the erythrocyte sedimentation rate, the concentration of sugar and cholesterol. In a coniferous forest on a sunny day, the number of air ions reaches 10 thousand per 1 cm3 of air, in the mountains up to 20 thousand, near waterfalls - up to 100 thousand. Having built houses, a person has practically deprived himself of the opportunity to breathe ionized air. In a residential area, the amount of negative air ions does not exceed 100...200 cm3. In office premises at the end of the working day, the amount of negative air ions drops to 25 ... 50 per cm3. Negative air ions are practically absent near TVs, monitors, office equipment, in rooms with air conditioners and forced ventilation. In such premises, there are mainly positive air ions that have a negative impact on a person. Almost all types of ionizers use the effluvial method of air ionization. It is as follows. If a high voltage is applied to the tip of the needle ("minus" to the needle, and "plus" to the ground), then electrons will "flow" from the tip ("effluvium" - in Greek "outflow"). Moving electrons on their way "stick" to oxygen molecules, forming negative air ions. A. Chizhevsky developed a number of requirements for air ionizers, it is especially important that the ionizer does not produce ozone and nitrogenous compounds. Since ozone and nitrogen dioxide are strong oxidizers. Radio amateurs design "Chizhevsky chandeliers", which use the effluvial ionization method. But since amateur designs are very different from the design proposed by Chizhevsky, either the efficiency of air ionizers is low, or they produce ozone and nitrogen oxides. So, most designs represent a high-voltage unit based on a modified output horizontal transformer of a television receiver with voltage multiplication. Due attention is not paid to the design of the electron emitter. There are no devices for measuring the number of air ions in 1 cm3 of air yet. Such structures perform the functions of air purification well, but as air ionizers they are ineffective, since the concentration of air ions necessary for a person is created in them at a short distance - in the zone of ozone formation. But there are designs that allow you to generate negative air ions without high voltage, due to the ball effect (spraying water). These are the so-called hydroionizers. There are mechanical and electronic hydroionizers. Water spraying is carried out using ultrasonic vibrations of a piezoelectric concave plate placed at the bottom of the tank. The electrical circuit of the generator of ultrasonic vibrations is shown in Fig.1.
On the elements DD1.1-DD1.3, a rectangular pulse generator is assembled at a frequency of 1,8 ... 2,0 MHz. Chip DD1 type 74AC04 on complementary field-effect transistors with a metal-oxide-semiconductor structure, which is a variant of the widespread series of transistor-transistor logic SN74, made it possible to obtain steep pulse fronts, low current consumption, small values of frequency-setting elements compared to a generator made on chip SN7404 (K155LN1). Element DD1.4 - buffer. From the output of DD1.4, the pulses are fed to the differentiating circuit C5R3. By changing the time constant of the RC circuit using the tuning resistor R3, you can change the duration of the pulses at the output of the elements DD1.5, DD1.6, therefore, the duty cycle of the pulses will change from 0 to 2. Thus, the power supplied to the piezoelectric BQ1 and the number of generated negative air ions are regulated. Since the threshold for opening a powerful MOSFET transistor VT1 is about 5 V, and significant currents are needed to quickly open and close the transistor, an amplifier must be used. As it is used chip DA2 IRF7105, consisting of two field-effect transistors: n-channel and p-channel. Characteristics of the n-channel transistor: drain current 3,5 A, power dissipation 2,0 W. Characteristics of the p-channel transistor: drain current 2,5 A, power dissipation 2,0 W. This amount of current, at a supply voltage of 2 V DA12, is enough to quickly recharge the input capacitance of the MOSFET transistor. At a low logic level at the output of DD1.5, DD1.6 opens p-channel transistor in DA2. In this case, +1 V is supplied to the gate of transistor VT5 through resistor R12, and transistor VT1 opens. At a high logic level at the output of DD1.5, DD1.6 opens the n-channel transistor in DA2. In this case, the gate of the transistor VT1 through the resistor R5 is connected to the common output of the power source, and the transistor VT1 closes. When the MOSFET is closed, the static capacitance of the piezoelectric element BQ1 is charged through the inductance L1. When the transistor VT1 is open, the static capacitance of the piezoelectric element BQ1 is discharged. In this case, the piezoelectric element experiences deformation. Oscillations of the piezoelectric element with ultrasonic frequency create longitudinal elastic waves in the liquid. When the piezoelectric element is located at the bottom of the container and filled with water to a level equal to the focal size of the piezoelectric element, a small fountain will rise from the surface of the water, accompanied by fog - fine water drops. These water drops are carriers of negative air ions. The design (Fig. 2) uses a concave emitter with a diameter of 30 mm and a focal length of 70 mm made of PZT piezoceramics at a frequency of 1,8 ... 2,0 MHz. A piezoelectric element 1 is glued into the brass body 2 using conductive glue. From below it is additionally pressed with a caprolon ring 5. The body is fixed at the bottom of the container 4 with a brass ring 10 and a sealing rubber ring 3. A massive brass washer 5 is pressed against the ring 11 from below with a caprolon sleeve 6 , which serves as a radiator for transistor 7. The washer has a hole for a conductor connecting the piezoelectric element to the drain of the transistor. MOSFET-transistor is fixed on the heatsink through an insulating gasket. The board with radio elements 8 is pressed from below with a caprolon ring 13. In the lower part of the case 1, on its outer side, there is an inductor 1 2 (L1 according to the diagram), wound on a dielectric frame. Power from the rectifier is supplied via a two-core shielded cable 14 through the central hole in the cover 15 of housing 1.
Setting up the electronic circuit is as follows. First of all, separately from the power transistor, the generator is tuned to the parallel resonance frequency of the piezoelectric element BQ1 using resistor R2. Resistor R3 sets the minimum pulse duration at the output DA2. Then the board is installed in the case and all connections are made. Settled water is poured into a container with an installed body. The filling level of the container is not higher than the focal length of the piezoelectric element. Voltage is supplied to the circuit from a current-limited source. By controlling the voltage with an oscilloscope at the connection point L1, the drain of the transistor VT1 and the piezoelectric element BQ1, by increasing the power with the resistor R3, a signal swing of 120 V is achieved from peak to peak. By adjusting the frequency with resistor R2, a minimum of current consumption from a source of +48 V is achieved. As a rule, the formation of the largest number of negative air ions is observed. PCB design. The radioelements are mounted on a round printed circuit board made of double-sided foil fiberglass. Installation is made on both sides of the board. Chips DD1 and DA2 in SMD version. Fixed resistors of size 1206, resistors of the C2-23 type with a power of 0,062 W can be installed vertically. Trimmer resistors R2, R3 type SPZ-19a. Permanent ceramic capacitors, size 1206. Electrolytic capacitors from HITANO, ECA series. Diode VD1 any pulse type KD522. MOSFET transistor VT1 type IRF630S, IRF730S in a D2-PACK package or similar, n-channel. Coil L1 contains 15 turns of PEV-2 wire with a diameter of 0,8 mm. According to the materials of the journal Radioamator Publication: cxem.net
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