SU787103A1 - Apparatus for emitting acoustic oscillations in closed cavity - Google Patents

Description

(54) DEVICE FOR RADIATING ACOUSTIC OSCILLATIONS IN A CLOSED VOLUME

one

The invention relates to instrument making and can be used to excite low frequency acoustic fields of traveling, standing waves and their combinations in studying the effect of these fields on various objects, as well as to conduct acoustic measurements.

A device for generating low-frequency acoustic fields of traveling waves, containing an oscillating wave that radiates sound waves into open space 1, is known.

However, such emitters are effective only if the size of the radiation surface is comparable to or exceeds the length of the emitted wave.

It is also known a device for generating low-frequency acoustic fields of standing waves generated by a plasma-type emitter in a limited volume of the resonator 2.

The length of this resonator must be a multiple of a quarter or half of the wavelength, and power consumption is also quite large. A resonator of this type is not suitable for generating low-frequency traveling waves.

The closest in technical essence to the present invention is a device for emitting acoustic oscillations in a closed volume, containing three actuators installed in a sealed chamber and connected through adjusting elements with a drive with three pulses, two of which are articulated and mounted with the possibility of creating a phase shift with respect to the third plasma shaft. 3

The disadvantages of this device should include 10 relatively low coefficient of its useful effect.

The purpose of the invention is to increase the efficiency of the device.

The goal is achieved due to the fact that the device chamber is equipped with a 15 partition, dividing the working volume of the chamber into two volumes isolated between each other, one of which is formed by the corresponding walls of the chamber, the partition and the ends of three walls, and the other by the corresponding walls of the chamber, recession and other sides of the ends of the same porschey.

The drawing shows a diagram of the proposed device.

The device contains a sealed chamber 1 with a single piston 2 and a system of two pistons 3 and 4, spaced apart in the working volume of the chamber and articulated with the possibility of simultaneous axial movement relative to each other. In chamber 1, a partition 5 is installed, dividing the working volume of chamber 1 into two volumes 6 and 7 insulated between themselves. Volume 6 is formed by the corresponding walls of chamber 1, one of the sides of the partition 5 and the end surfaces of pistons 2 and 3-4, and volume 7 formed by the corresponding walls of the chamber 1, the reverse side of the partition 5, the air duct 8 and the reverse face surfaces of the widths 2 and 3-4. The pistons 2 and 3-4 through the rods 9 and 10 and the corresponding displacement adjustment elements 11 and 12 are associated with a common drive, for example, consisting of an electric motor 13, a gearbox 14 and rocker mechanisms 15 and 16. The entry points of the rods into the volumes are sealed. The displacement adjustment elements 11 and 12 consist, for example, of planes 17 and 18 mounted on the output axes of the reducer and the fingers 19 and 20 installed with the possibility of radial and azimuthal displacements relative to the axes of the faceplates. The elements for adjusting the movements of the pistons 2 and 3-4 are adjusted so that there is a phase shift in the mutual position of the single piston 2 and the jointed 3-4 wheels relative to their middle positions.

The device works as follows. When the electric motor 13 is turned on, the torque is transmitted through the gearbox 14 to the plate 17 and 18 of the displacement adjustment elements 11 and 12. The fingers 19 and 20 are driven back and forth by the rocker mechanisms 15 and 16 and associated with them through the rods 9 and 10 of the corresponding gears 2 and 3-4. The oscillatory speed in volumes 6 and 7 is created by the in-phase movement of the pistons 3-4, and the acoustic pressure is created by the movement of the piston 2, and the pressure phases in volumes 6 and 7 are opposite to each other. The amplitudes of piston oscillations, which determine the magnitudes of the oscillatory velocity (at a given frequency) and acoustic pressure, are controlled by moving the respective fingers along the faceplate plane, and the phase shift between the components of the fingers set with the initial angle shift relative to each other on the faceplate plates necessary for each type of acoustic field generated. With equal volumes of 6 and 7 (taking into account the volume of the duct 8), the ratios between the components of the acoustic fields in these volumes will also be the same. To create in the volume of 7 oscillations only the acoustic pressure or only the oscillatory velocity respectively, the air line 8 overlaps or closes (with the open air line) to the walls of chamber 1 partition 5. At the same time, volume 6 will still generate an acoustic field with the parameters of a traveling or standing wave .

Using the proposed device, improve the efficiency of the pathogen and conduct research on the effects on various objects of individual

components of powerful low-frequency acoustic fields and co-operation of these components, which takes place in the field of traveling or standing waves, in addition, acoustic measurements are carried out, for example, calibration of low-frequency receivers of a wide dynamic range.

Claims (3)

1. Tyulin V. N. Introduction to the theory of radiation and sound scattering. M., "Science, GRFML, 1976, p. 140. 2. The collection of reports Jnfra-sons, Collogues Jnternationaux, Paris, ed. L. Pimonov. 1974, p. 36 3. USSR author's certificate Application No. 2677370 / 18-10, cl. B 06 B 1/02, 1976.