DIRECTED ULTRASONIC TRANSDUCER FOR GAS ENVIRON-MENTS

JVUOZV

Abstract

The article is devoted to the creation of highly efficient ultrasonic emitters for gaseous media with an increased level of generated sound pressure and a narrow directional pattern. The need to create such an emitter is determined by the existence of a large number of technological processes, to intensify which it is necessary to generate directed sound radiation with a sound pressure level of more than 150 dB, at a distance of more than a meter from the emitter. Unfortunately, existing ultrasonic emitters do not provide the required sound pressure levels due to the low acoustic impedance of gaseous media, and the mutual compensation of radiation generated by sections of the emitter oscillating in antiphase.

As part of the study, a design of the emitter was proposed, consisting of a piezo-electric transducer and a disk of variable cross-section. To form a narrow radiation pattern, use radiation from the backside of the disk and eliminate mutual compensation of oscillations, reflectors and phase-equalizing cones were developed. To determine the characteristics of the created emitter, measurements of sound pressure and radiation patterns were carried out in various configurations: without additional devices, with a reflector, with a reflector and phase-equalizing cones.

The results of the study showed that the use of a reflector increases the sound pressure level by 3-3.5 dB, and the addition of phase-equalizing cones makes it possible to achieve a pressure close to 150 dB and reduce the angle of the main lobe of the radiation pattern to ±4 degrees. Thus, the proposed design significantly improves the efficiency of the emitter, directing most of the energy to the main lobe and increasing the range of ultrasonic radiation.