Design of multi-function ultrasonic micro atomizer

The author introduces a multi-purpose ultrasonic atomizer. The atomizer has the following features: split type, that is, the ultrasonic atomizing head is completely separated from the power source and the circuit part; portable, small in size, plug and play, and has a self-protection function; high reliability, can work around the clock; Large, with the villa's landscape bonsai can occur cloud-like dynamic; especially suitable for excessive dry environment to humidify the air, to facilitate human breathing; add a certain amount of solvent in the water to disinfect the contaminated living environment to prevent Diseases (such as the timing of life with vinegar atomization, can prevent influenza); atomizer (finished products) low price, cost-effective, want to make atomizers, only equipment and working hours are also difficult to meet the above cost.
First, the working principle of the circuit The atomizer circuit is shown in Figure 1. The power supply is stepped down by the transformer B (AC220V/30W) (36V) to send D1-D4 rectification and C5, C6 filtering to provide the working voltage to the circuit. The nebulizer working circuit is composed of an oscillator, a transducer and a water level control circuit.
1. Oscillator and transducer, the oscillator in the circuit is a working oscillator composed of high-frequency piezoelectric ceramic TD (ultrasonic transducer), the oscillation frequency is 1.65MHz (depending on the selected TD) ). Transistor BG1 (transistor is one of the basic components of semiconductors, has current amplification, is the core component of electronic circuits. The triode is to make two closely spaced PN junctions on one semiconductor substrate, two PN junctions are positive The block semiconductor is divided into three parts, the middle part is the base area, the two sides are the emitter area and the collector area, and the arrangement is PNP and NPN.) The capacitors C1 and C2 form a capacitor three-point oscillator circuit. The equivalent resonant frequency of C1 and inductor L1 is lower than the operating frequency, and its function is to determine the working oscillator (the oscillator (which is the electronic component used to generate repeated electronic signals (usually sine or square waves). It is called an oscillating circuit. It can convert DC power into an electronic circuit or device with a certain frequency of AC signal output. There are many types, which can be divided into self-excited oscillator and other oscillator according to the oscillation excitation mode. Oscillator, inductor-capacitor oscillator, crystal oscillator, tuning fork oscillator, etc.; according to the output waveform can be divided into sine wave, square wave, sawtooth wave and other oscillators. Widely used in electronics industry, medical, scientific research, etc.) Oscillation amplitude; C2 and inductor L2 equivalent series resonant frequency is higher than the operating frequency, its role is to determine the feedback amount of the working oscillator to ensure oscillator oscillation and maintain reliable oscillation of the circuit. Piezoelectric ceramic TD has a large The equivalent inductance, in addition to determining the operating frequency of the circuit, is also the working load of the atomizer. If the piezoelectric ceramic piece TD is replaced, there is no need to adjust the circuit.
2. The ultrasonic transducer TD (also known as the atomizing head) in the water level control and bias circuit and the two water level control stylus mounted thereon are immersed in a shallow aqueous solution. If it is atomized for a long time, once the liquid level is lowered and the water level control stylus of the atomizing head is exposed to the water surface, the oscillator will automatically stop working, which also prevents the atomizing head from being damaged by heat.
The BG2, BG3, stylus A, B and associated resistors in the circuit of Figure 1 together form a water level control circuit. When the circuit is in operation, the power supply supplies power to the emitter of BG3 through stylus A, B and aqueous solution. The BG3 tube is turned on. The BG2 tube acts as a switch. When BG3 is working, the BG2 tube is also turned on, and the power supply supplies bias current to the BG1 tube through BG3, BG2, R3, and L3, so that the BG1 tube oscillates. Once the liquid level is lowered and the control stylus is exposed to the water surface, the path of the power supply to the BG3 tube is cut off, the BG3 tube is turned off, and the BG2 switch is also turned off. At this time, the BG1 stops oscillating rapidly due to no bias current. Adjusting the resistance of resistor R3 can directly change the bias current of BG1 tube, so the debugging of the oscillator is very simple and convenient. D7 in the circuit is the protection diode of the BG1 tube be junction.
Second, the structure and use of ultrasonic atomizer
1. The structure of the atomizer, the shape of the atomizer is shown in Figure 2. The outer casing of the atomizing head is made of a copper material. The surface of the copper shell is chrome-plated and polished. The outer dimensions are 442mm×l5mm. The copper shell is packaged with a transducer (nickel or titanium high-frequency piezoelectric sheet) and the power tube BG1. The device is placed close to the BG1 tube to dissipate heat in the solution during operation. The cast copper shell is detachable, and the piezoelectric sheet can be replaced by simply rotating the positioning opening on the shell surface. In addition, the two water level control styli are fastened in the copper shell and arranged at a certain distance and then vertically protruded to a certain height outside the shell to control the lowest water level of the atomized solution.
2, the use method, if the atomizer is used for indoor humidification or disinfection, a small plastic pot can be prepared, the pot contains a certain amount of solution, the amount of the solution should not be too much (shallow water), only higher than the water level stylus A certain distance (the solution is too deep and the amount of atomization is relatively reduced). Then place the atomizing head flat and immerse the two styluses in the solution. At this time, just plug in the power and the solution starts to atomize immediately. If the atomizer is used for a bonsai, it can be carried out by referring to the above method.