US2804042A

US2804042A - Apparatus for producing high-powered sounds and ultra-sounds

Info

Publication number: US2804042A
Application number: US491089A
Authority: US
Inventors: Gavreau Vladimir
Original assignee: Centre National de la Recherche Scientifique CNRS
Current assignee: Centre National de la Recherche Scientifique CNRS
Priority date: 1954-03-02
Filing date: 1955-02-28
Publication date: 1957-08-27
Anticipated expiration: 1974-08-27

Description

Aug. 27, 1957 v GAVREAU 2,804,042

' APPARATUS PRODUCING HIGH-POWERED SOUNDS AND ULTRA-SOUNDS Filed Feb. 28, 1955 2 Sheets-Sheet 1 Gavv'eeu INVENTUR 41L ATTUHNEYJ.

Aug. 27, 1957 v GAVREAU 2,804,042

APPARATUS PRODUCING HIGH-POWERED SOUNDS AND ULTRA-SOUNDS Filed Feb. 28, 1.955 2 Sheets-Sheet 2 BY" Q- W ATTORNEYS.

United States Patent fifice 2,804,042 Patented Aug'. 27, 1957 APPARATUS PRODUCING HIGl-LPOWERED SOUNDS AND ULTRA-SOUNDS Vladimir Gavreau, Marseille, France, assignor to Centre National de la Recherche Scientifique, Paris, France, a French society Application February 28, 1955, Serial No. 491,089 Claims priority, application France March 2 1954 3 Claims. (Cl. 116-137 The present invention relates to apparatus for emitting sounds or ultra-sounds in a liquid mass.

Up to this time the apparatus used for this purpose were capable of transmitting but very little energy into the liquid mass. The power developed by quartz or magnetostriction apparatus is very limited and the sounds produced by sirens, which are powerful, practically do not penetrate liquids.

The object of the present invention is to obviate this difliculty.

For this purpose the apparatus according to my invention includes a chamber separated from the mass of liquid by a flexible diaphragm and means for producing in said chamber a succession of pressure oscillations, said means, which include a rotary distributing valve device, intermittently and repeatedly placing said chamber. in communication with a discharge space at a frequency of repetition Within the range of sound and ultra-sound frequencies, through at least one orifice and introducing into said chamber, through said orifice a gaseous fluid at a pressure higher than that existing in said discharge space during every period between two successive time periods for which said chamber is in communication with said discharge space, said means being arranged to close said orifice for a short time between every period of introduction of gaseous fluid into said chamber and the next period of communication ofsaid chamber with said discharge space, during which short time said chamber is wholly closed.

Preferred embodiments of my invention will be hereinafter described with reference to the accompanying drawings, given merely by way of example and in which:

Fig. l is an axial section of an apparatus made according to a first embodiment of my invention, the righthand half of this figure showing a relative position of the parts slightly different from that shown by the left-hand half.

Fig. 2 is a similar view of an apparatus made according to another embodiment of said invention.

The apparatus shown by Fig. 1 includes a fixed casing C on the top of which is fixed a container 11% 32 with a mass of liquid 33 therein. is provided with a circular row of holes 9 which are separated from the liquid 33 by a diaphragm 26 held between casing C and container 11-32j In casing C and in a hub 12 fixed thereto, there is journalled, at 19 and 20 (18 being a packing box), a shaft 17 carrying a rotor made of two

parts

51 and 52 rigid with each other. This rotor divides the inside of casing C into two

coaxial compartments

24 and 30. Compartment 24 communicates through a conduit. 2.7 with The top plate of casing C' a source of compressed air. Compartment 30 communicates through a conduit 31 with the atmosphere or any other discharge space. The rotor 51-52 is provided with a circular row of passages, the total number of said passages being equal to twice the number of holes 9. Every second passage 281-4282 extends between compartment 24 and the under face of the top' plate of casing C. The other passages 291.-292 (each located in a radial plane of the rotor located between two radialplanes corresponding to two consecutive passages 2fi1-282) extend between the under face of said top plate of casing C and the other compartment 30. The

portions

282, 291 of these passages are"l.o-cated at the same distance from the axis of rotation of shaft 17.

During'the rotation of rotor 5152 there is a position (shown by the left-hand half of Fig. 1) for which all the passages 281-282 are in register with holes 9 which are then filled With compressed air from conduit 27 so that a substantial pressure is exerted on diaphragm 26. Then the rotor, after further rotation through a small angle, during which holes 9 communicate neither with passages 281-382 nor with passages 291-492, passes through a position (shown by the right-hand side of Fig. 2) where holes 9 are placed in communication, through passages 291-292, with compartment 30 and discharge pipebal so that there is a sudden drop of the pressure exerted on diaphragm 26.

The air pressure at 27 may be one or several kilograms per square centimeter; the discharge pressure at 31 may be of the order of magnitude of l kg./cm. or more, if, for example, the apparatus is used for the trans.- mission of under water of sound signals at a substan+ tial depth or if a pressure higher than atmospheric pres? sure exists in the container 11-32 where the liquidis' to be treated. Within holes 9, the pressure rapidly at? tains a value close to that of the feed pressure, then drops as quickly. Thus the air pressure'within holes '9 oscillates with an amplitude of several lag/cm. and these substantial pressure variations are transmitted to the liquid through diaphragm 26.

It is known that the variations of instantaneous pres; sure corresponding to sound waves transmitted in the atmosphere are of the order of several grams per cmfi while in order to produce sound waves of the same'ih-I:

tensity in liquids, pressures of several kilograms per'cm.

g must 'be used. Thus a given acoustic intensity (in watt/ cm?) in the atmosphere corresponds to pressures in Water 59 times greater (and to amplitudes 59 times smaller).

For this reason, an absolutely negligible portion of e the sounds transmitted by the air of the atmosphere can penetrate liquids, and until the present the time :use of sirens for the acoustic treatment of liquids (ultra sound treatment, for example) has not been successful. If sound or ultra-sound Waves are applied to a thin' sheet of liquid falling freely through space, this sheet will vibrate as a whole Without, however, the sound being able to penetrate it. And the only eifect that can be obtained by this means is a pulverization having nothing in com-. men with the different useful effects produced by ultrasounds transmitted into the very interior of a liquid mass.

Experiment shows'tha't the strong compressions and depressions produced in the holes 9 of the apparatus of Big. I achieve the transmission of very intense sounds in the liquid mass. An important cause of the poor over-all efiiciency of sirens is loss charge in the compressed air P p and e g rally PQor output .of-air compressors."

. Moreover, the compression present invention) any other compressed gas can 'be used instead of air; this compressed gas maybe introduced into suitablylocated chamber or chambers in the stator or rotor, in the form of a mixture of a combustible gas or vapor with air or oxygen, the desired pressures in said chamber being developed by combustion or explosions of this mixture therein.

For this purpose I may make use of an apparatus as shown by Fig. 2.

The general arrangement is the "same as that of Fig. 1. But holes 9 communicate with a chamber 35 separated from'the liquid mass 33 by diaphragm 26. In this chamber 35 is provided a spark plug 34 operated, in a conventional fashion, to give a spark every time the rotor 51-52, after placing holes 9 and chamber 35 in communication with a carburetter mounted on pipe 27, has

just cut 01f said communication. Furthermore a suction is exerted in compartment 30 by a pump mounted on pipe 31.

It is evident that under these conditions four phases in the operation of this siren can be distinguished:

1st phase.The chamber 35 being in communication, through pipe 31, with the suction pump, a depression is formed therein.

. 2nd phase.Communication is cut 01f between chamber 35 and passages 291'292.

3rd phase.Immediately thereafter, chamber 35 comes into communication with the feed tube 27, by means of the vertical passages 281-282 of rotor 5152.

4th phase.The rotor further turns (driven by an electric motor) and passages 281-282 are closed. The ignition is timed for this moment. A certain degree of pressure (on the order of several kg./cm. exactly as in the explosion motor of a motorcycle or automobile, is exerted against diaphragm 26 which, itself, practically does not move, being held in place by the liquid 33 contained in the reservoir 11-32 on the other side of the membrane;v The interior of chamber 35 is then again placed in communication with the suction pump by means of tube 31 and passages 291-292. The gases resulting from the combustion (or explosion) are evacuated by this suction pump and the cycle begins again.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and efficient embodiments of my invention, it should be well understood that I do not wish to 'be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

What I claim is:

1. An apparatus for emitting sounds or ultra-sounds in a liquid mass which comprises, in combination, a container for said liquid mass having a portion of its wall constituted by a flexible diaphragm, a fixed structure forming at least one gas chamber contiguous to said container along at least a portion of said diaphragm, which thus forms a thin and flexible partition between said chamber and said liquid mass, said gas chamber having at least one orifice, a rotary distributing valve device for intermittently and repeatedly placing said chamber in communication through said orifice with a discharge space, at a frequency of repetition within the range of sound and ultra-sound frequencies, and means including said distributing valve device for introducing into said chamber through said orifice a gaseous fluid at a pressure higher than that in said'discharge space during every period between every two successive time periods where said chamber is in communication with said discharge space,.sa id means .being arranged to close said orifice for.

a short time between every periodlof introduction of gaseous fluid into said chamber and the next period of communication of' said chamber with said discharge space, during which short time said chamber is, wholly closed.

2. An apparatus for emitting sounds or ultra-sounds in a liquid mass which comprises, in combination, a container for said liquid mass having a portion of its wall constituted by a flexible diaphragm, a fixed structure including a plate provided with a multiplicity, of holes disposed in a circular row, said holes extending throughout said plate and said flexible diaphragm being located adjacent to said plate on one face thereof, whereby said holes form gaschambers limited on one face of said plate by said diaphragm, each of said chambers having one orifice opening into the other face of said plate, conduit means leading to a discharge space, asource of gaseous fluid at a pressure higher than that in said discharge space, and

, distributing means including a casing in the form of a chosen to achieve a frequency of repetition of the feed a of said gaseous fluid to said chamber within the range of V 'body of revolution about an axis at right angles to said plate and passing through the center of said circular row of holes, said casing forming two concentric compartments, one in communication with said source and the.

other with said conduit means leading to said'discharge space, and a rotor journalled about said axis having a flat face adjoining said plate on the second mentioned face thereof and including a multiplicity of passages, every second passage of said rotor being arranged, for a given 1 position of said rotor about its axis to register with one of said orifices so as to connect said first mentioned compartment with one 'of said chambers wherebyall of said chambers are then fed with gaseous fluid from said source, and every other passage of said rotor being arranged to connect, after a small rotation of said rotor, one of the same orifices with said second mentioned compartment, whereby all of said chambers are 'then in communication with-said discharge space, the speed of rotation of said rotor and the number of said holes being sound and ultra-sound frequencies.

3. An apparatus for emitting sounds or ultra-sounds in a liquid mass which comprises, in combination, a container for said liquid mass having a portion of its wall constituted by a flexible diaphragm, a fixed structure forming a gas chamber contiguous to said container along at least a portion of said diaphragm which thus form a thin and flexible partition between said liquid mass and one end of said chamber, said structurefurther including, at the other end of said chamber, a plate provided with a multiplicity of holes disposed in a circular row, said holes extending throughout said plate, conduit means leading to a discharge space, means for supplying a carbureted mixture of fuel and comburent at a pressure higher than that in said discharge space, distributing means including a casing in the form of a body of revolution about an axis at right angles to said plate and passing through the center of said circular row of holes, said casing forming,

, flat face adjoining said plate on the face thereof opposed to that located in said chamber, said plate including" a multiplicity of passages, every second passage of said rotor being arranged, for a given position of-said rotor about its axis, to register with one of said holes so as to connect said first mentioned compartment with saidv chamber whereby said chamber is then fed with said carbureted mixture, and every other passage of said rotor being arranged to connect, after a small rotation of said rotor, one of the same holes with said second mentioned compartmenh'whereby said chamber is then in communication with said discharge space, and means in said chamher operative in synchronism with the rotation of said.

rotor for igniting said mixture in said chamber when said References Cited in the file of this patent holes are closed by said rotor, the speed of rotation of UNITED STATES PATENTS said rotor and the number of said holes being chosen to achieve a frequency of repetition of the successive igni- Elfman 1938 tions within the range of sound and ultra-sound frequen- 5 2500008 Richardson 1950 cies. FOREIGN PATENTS 977,783 France Nov. 15, 1950