How does the transducer work in an ultrasonic cleaner?Date: 2022-11-08Number: 218
There are two types of ultrasonic cleaning Ultrasonic transducer: magnetostrictive Ultrasonic transducer and piezoelectric Ultrasonic transducer. The former is hardly needed at this stage because of its high cost and low electro-acoustic efficiency Piezoelectric Ultrasonic transducer are widely used in ultrasonic cleaning machines due to their high efficiency, low cost and convenient installation. Most of the piezoelectric Ultrasonic transducer are of single-screw-fastened longitudinal vibration Ultrasonic transducer, consisting of two piezoelectric ceramic chips with central perforations and a front and rear cover plate.
To ensure the stability and efficiency of the cleaning machine, a semi-perforated broadband Ultrasonic transducer has also been developed, the structural features of this kind of Ultrasonic transducer are to drill a certain number of holes uniformly along the axial direction of the radiating surface of the Ultrasonic transducer to form a semi-perforated structure with the same depth. The greater the hole diameter, the wider the bandwidth at a certain hole depth, and the deeper the hole, the wider the bandwidth at a certain hole area. These Ultrasonic transducer are about twice as wide as the average Ultrasonic transducer band and can be up or down to ± 2 khz. Their electro-acoustic efficiency can still exceed 80% within the bandwidth range, the utility model has the advantages of higher working efficiency than the ordinary Ultrasonic transducer, and thus solves the inconvenience caused by the parallel connection of multiple Ultrasonic transducer due to the narrow bandwidth of the ordinary Ultrasonic transducer in the high-power ultrasonic cleaning machine. The semi-perforated structural Ultrasonic transducer can also reduce the lateral vibration of the radiation range, which is beneficial to the increase of the radiation range of the high-frequency Ultrasonic transducer, and is beneficial to the product performance of the ultrasonic cleaning equipment.
Recently, a dual-frequency Ultrasonic transducer has been developed. The dual-frequency Ultrasonic transducer has two resonant frequencies. This dual-frequency Sonication can greatly improve the acoustic field of the cleaning cylinder, improve the cleaning effect. These Ultrasonic transducer are usually made up of three sections: the first section is the longitudinal piezoelectric oscillator, the second section is the horn, and the third section is the radiator, the third section is made of stainless steel or titanium alloy with high fatigue resistance and treated by special process.
At present, there are two kinds of ultrasonic cleaner generator, one is the self-excited type D transistor (or module) switching power amplifier which is widely used in the late 1970s and early 1980s. The main feature is simple circuit, the Ultrasonic transducer is a self-excited oscillator components, so with the change of load frequency, oscillator frequency can change with the change, has the frequency tracking effect. It is easy to realize the high-power ultrasonic generator by multi-channel synthesis, and the circuit has good stability and maintainability. Its main disadvantage is unprotected circuit, power can not be continuously adjusted. The other kind of ultrasonic generator is a power amplifier circuit of switching power supply circuit, which uses a power module in the final stage, and its pre-control is either analog or digital, all adopt PWM (pulse width modulation) mode, the frequency can be adjusted, pulse width can be adjusted, characteristic frequency stability is good, power can be continuously adjusted. Because the use of high-voltage, high-current IGBT or M0S module, high-power cleaning ultrasonic generator with smaller size, better stability, and the switch power supply circuit control circuit technology is advanced (0.53 kw single-panel generator has been commercial) , is one of the ultrasonic cleaning generator development trend.