US3410532A - Liquid treatment apparatus with sonic wave action - Google Patents

Description

A. e. BODINE 3,410,532

LIQUID TREATMENT APPARATUS WITH SONIC WAVE ACTION 7 Nov. 12, 1968 2 Sheets-Sheet 1 Filed Oct. 24, 1965 INVENTOR. ALBERT G. BODINE BY R2" ATTO NEY 2 Sheets-Sheet 2 A. G BODINE LIQUID TREATMENTAPPARATUS WITH SONIC WAVE ACTION Nov. 12, 1968 Filed Oct. 24, 1965 WW s WWWA TM m m w .hm:w m W13 United States Patent O "ice LIQUID TREATMENT APPARATUS WITI-I SONIC WAVE ACTION Albert G. Bodine, 7877 Woodley Ave., Van Nuys, Calif. 91406 Continuation-impart of application Ser. No. 341,608, Jan. 31, 1964. This application Oct. 24, 1965, Ser. No. 504,447

11 Claims. (Cl. 259-4) ABSTRACT OF THE DISCLOSURE Apparatus includes an enclosure containing a large stationary inertial mass. The inertial mass is opposed by a vibratory mass spaced therefrom. Liquid to be treated is disposed between the two masses. The vibratory mass is secured to one region of an elastic member, which may extend through one end of the enclosure and is driven at another region by a sonic wave generator. The generator operates at the resonant frequency of the system.

This application is a continuation-in-part of application Ser. No. 341,608 filed Jan. 31, 1964, now Patent No. 3,284,010, which is a continuation-in-part of application Ser. No. 200,091, filed June 5, 1962, now Patent No. 3,131,878.

This invention relates generally to apparatus for processing fluid substances and more particularly to such apparatus for bringing about such treatment as distribution, changes in particle size, molecular cracking, intermingling, and homogeneity of one or more liquids with or without contained solids, by means of intense sonic wave action.

Heretofore, various devices have been employed to process fluid substances. For example, various types of mechanical mixing devices have been employed to bring about distribtuion, intermingling, and homogeneity of fluid substances. Other devices, such as colloid mills, have been used to reduce the size of particles in a fluid stream, to create emulsions, to break down agglomerates, or to break emulsions into finer particulates.

In my copending application Ser. No. 343,852 filed Feb. 10, 1964, entitled Method and Apparatus for Extracting Juice From Vegetable Matter, there is shown apparatus employing sonic wave action for fluid cavitation processing. The apparatus disclosed therein is particularly adapted for dispersing a fluid into a solid or similar fluid processing of solid material. In the present invention the sonic wave action is employed in the treatment of one fluid relative to another.

Differences in the type and amount of mixing can affect such processes as chemical reactions, reaction rates, and the rate of transfer of matter between phases. Thus, in chemical research and processing, the type and amount of mixing must be controllable so that these various processes can be regulated.

Mixing has been accomplished heretofore by a great variety of equipment. Prior to the present invention fluid mixing usually has been done by rotating impellers that operate in cylindrical vessels. In such apparatus that impeller is driven by a shaft via a power transmission device to prime mover.

A mixer produces mechanical effects only. Molecules of themselves will diffuse, but mixing impellers produce flow which results in forced convection. Hence, reactants can be brought to an interface as rapidly as desired by controlling the forced convection currents with mixers. There are at least five distinct types of operations in which fluid mixers are used: blending of miscible fluids; stirring of immiscible liquids for extraction, emulsification, and other processes; suspension and dissolving of solids, agita- 3,410,532 Patented Nov. 12, 1968 tion of gases and liquids; and heat transfer. These may be batch or continuous operations but in each case energy must be supplied to produce fluid motion. Mixer performance criteria will be different for each, but the fluid motion produced by the impeller and system is the controlling factor.

Fluid motion on both a large-scale (mass flow) and a small-scale (turbulent) are ordinarily required to bring about rapid mixing. However, some mixing operations require relatively large mass flows for best results, while others require relatively large amounts of turbulence. There is usually an optimum ratio of flow to turbulence for a desired mixing operation, whether it is a simple blending of immiscible liquids or a mass-transfer operation followed by chemical reaction.

Apart from mixing operations, various specialized devices have been employed heretofore to accomplish each of the above-mentioned processes. For example, a specific class of device used for particle reduction is known as a colloid mill. These devices employ sharp shear gradients in a fluid medium to rupture solid particles which are generally friable, to break down agglomerates, and to create emulsions or to make the suspended liquid droplets finer. Because of the speeds, the contact surfaces of these devices are subject to wear from the more abrasive particles. When they are used to break emulsions into finer particulates, devices within this class are usually referred to as homogenizers. Colloid mills of the prior art generally contain a motor-driven rotor turning within a stator ring. The shear is developed in the liquid as it is pumped across the closely spaced faces of the rotor and stator. Static devices have also been used such as small nozzles or orifices through which the liquid is pumped.

But a few of the many prior art devices employed to process fluid substances have been mentioned as being representative. However, any of the above-mentioned processes such as mixing, homogenization, accelerating chemical reactions, and dispersing one fluid into another may be accomplished by means of the novel apparatus of the present invention. Unlike devices of the prior art, the apparatus of the present invention subjects fluid substances to high-intensity, high-impedance sound waves. A sound wave of high impedance as used herein denotes a sound wave (that is, a wave of alternating compression and rarefaction) characterized by a high ratio of applied cyclic pressures or force to amplitude. In a broader sense, the present invention is based upon the application of sonics to cause rapid changes in pressure and density such as to have advantageous eflects in the treatment of one fluid relative to another, or of chemical reactions or molecular changes in a single fluid.

It has been proposed heretofore to couple acoustical energy into a vessel for mixing, cleaning, and chemical activation. However, these prior systems have been highly inefficient as regards utilization of the power input and have been undesirably sensitive to the properties of the liquids in the vessel. In the present invention the efficiency of the system is not greatly affected by the state of the liquid being treated.

Typical prior devices employ an electroacoustic transducer of the piezoelectric type or of the magnetostrictive type. These transducers are very expensive for their size and are necessarily small relative to the wavelength of the acoustic energy which they generate. On the other hand, electrodynamic or variable-reluctance types of electroacoustic transducers are extremely bulky and therefore expensive and uneconomical as regards their power output. Additionally, all of the aforementioned transducers require special power supplies which, in addition to their relative expense, are costly to maintain.

Prior systems are also characterized by the fact that the volume of the liquid-containing vessel is relatively large compared to the wavelength of the sonic energy propagated therein and in many instances this is an undesirable characteristic. The present invention overcomes the above-discussed shortcomings of prior systems in that it provides a powerful, rugged, highly-reliable, mechanical system having a very high efiiciency for its weight and volume.

The present invention is particularly suitable for dispersing one fluid into another, for the formation of emulsions and for the intimate mixing of high viscosity liquids. An additional important application is in the dispersion of granules, powders, pigments and so forth into liquids. The invention is also broadly applicable to sonically producing or accelerating chemical processes which respond to such energy input, particularly at high sonic energy levels.

It is, therefore, an object of the present invention to provide a novel and improved sonic liquid treatment machine of all mechanical construction which is simple in design, safe, reliable, and easy to maintain.

Another object of the invention is to provide a novel and improved sonic liquid treatment machine in which the reactances of the acoustic circuit have very high values, and are all contained within a controlled, solid structure machine.

Yet another object of the invention is to provide a liquid treatment machine which does not rely upon wave action of the liquid itself to obtain the desired results.

Still another object of the invention is to provide a novel and improved sonic liquid treatment apparatus having a higher Q in the sonic circuit as compared with prior devices, and wherein the acoustic circuit termination delivering power to the liquid sees a large resistive impedance, and also has a high reactive impedance in the same termination point.

Yet another object of the invention is to provide a novel and improved sonic liquid treatment apparatus wherein the sonic circuit is in the machine itself apart from the liquid being treated and which confines the treatment region of the liquid to a small volume having very high energy concentration and uniform energy density, wherein cyclic pressure change is maintained at high values throughout.

Still another object of the invention is to provide a novel and improved liquid treatment apparatus wherein the dimension of the wave transmission path within the liquid is sufiiciently short that no appreciable wave pattern takes place within the liquid, and wherein there is an extensive dimension in the machine itself permitting a substantial wave pattern to exist within high-impedance solid structures of the apparatus, and which has a high acoustic Q.

It is still another object of the invention to provide a novel and improved sonic liquid treatment apparatus capable of generating very high sonic power and which accommodates high rates of flow through a small area so that the liquid has a small residence time in the sonic field.

It is another object of the invention to provide a novel and improved mechanoacoustical system having a powerful, relatively low frequency, mechanical oscillator, for the treatment of liquids.

Yet another object of the invention is to provide novel and improved apparatus for generating powerful lowfrequency elastic vibrations in a liquid, said vibrations having a long equivalent wavelength, so that cavitation bubbles" produced thereby are large and very powerful.

Another important object of the present invention is to provide a novel and improved liquid processing apparatus operating upon novel sonic wave principles, and which is more effiicent than devices heretofore intended to accomplish generally similar functions.

Still another object of the invention is to provide novel and improved means for confirming the treated volume under high sonic pressure in order to produce hard cavitation therein.

It is still another object of the invention to provide novel and improved sonic wave apparatus for treating fluids, in which the fluid is mainly a resistive impedance in the acoustic circuit.

In the apparatus of the invention the liquid to be acted upon is acoustically coupled into an acoustic circuit, where it is continuously subjected to an acoustic wave action which results in cavitation and intense turbulence. The invention will be more fully understood from the following detailed description of certain illustrative embodiments and by way of reference to the accompanying drawings, in which:

FIGURE 1 is aside elevation view, partially in section, of a first embodiment of the invention;

FIGURE 2 is a top plan view of the apparatus of FIGURE 1;

FIGURE 3 is a side elevational view, partially in section, of an alternate embodiment of the invention;

FIGURE 4 is a side elevation view, partially in section, of still another embodiment of the invention; and

FIGURE 5 is an equivalent network diagram which is useful in the exposition of the invention.

To facilitate an understanding of the invention the following definitions are set forth:

Impedanceln an elastically vibratory system impedance is the complex quotient of applied alternating force and linear velocity. Impedance may be expressed mathematically as:

M=vibratory mass C=elastic compliance f=vibration frequency R=resistance Resistance'lhe real part R of the impedance, and represents energy dissipation, as by friction.

Reactance-The imaginary part of the impedance, and is the difference of mass reactance and compliance reactance.

Mass reactanceThe positive imaginary part of the impedance, given by Zn-fM. It is analogous to electrical inductive reactance, just as mass is analogous to inductance.

Elastic compliance reactance-The negative imaginary part of impedance, given by l/21rfC. Elastic compliance reactance is analogous to electrical capacitance reactanc just as compliance is analogous to capacitance.

ResonanceThe condition obtained in a vibratory circuit at the operating frequency at which the reactance (the algebraic sum of mass and compliance reactance) becomes zero. Vibration amplitude is limited under this condition to resistance alone, and is maximized. The inertia of the mass elements necessary to be vibrated does not consume any of the driving force under a resonance condition.

The basic structure, common to all embodiments of the invention to be described hereinafter, employs a massive stationary, or out-of-phase motion, element and a massive vibratory element, the latter of which is sonically activated into powerful vibratory movement by a resonant elastic system coupled thereto. The massive vibratory element will be referred to hereinafter as an impeller. The complete resonant system of the impeller and its mechanical input is sonically driven to powerful elastic resonance by means of a mechanical sonic generator having a high cyclic force (high impedance) output. A high-strength, high-impedance capacitance in the form of an elastic bar tunes with the inductance of the system which may comprise the impeller and the mass of the oscillator housing acoustically coupled thereto.

Looking now at FIGURE 1 there is shown a first embodiment of apparatus incorporating the novel features of the invention. This embodiment comprises a liquid containing tank formed by end members 1 and 2 extending upwardly from floor member 3, which is in turn mounted on a pair of I-beams 4 and 5 which elevate the apparatus above the floor 6. Side walls 7 and 8, shown in FIGURE 2, complete the tank structure. End members 1 and 2 have a large inertial mass, and each is in the general form of a rectangular block. The vibratory mass comprising the impeller 9 is secured to one end of an elastic, longitudinally vibratory rod of shaft 11, preferably fabricated from steel which permit good elastic wave action therein without fatigue. The opposite end of shaft 11 supports, and is acoustically coupled to, a sonic wave generator, indicated generally at 12. Generator 12 is capable of imparting longitudinally oriented, elastic, sonic wave action to shaft 11, the nature of which will be described more fully hereinafter.

Generator 12 is mounted on stand 13. As can best be seen in FIGURE 2 the generator 12 comprises a housing 14, which contains a pair of orbiting weights, and has a drive shaft 15 extending therefrom. Shaft 15 is driven by motor 16 through suitable pulleys and drive belt 17. Shaft 11 is bolted to housing 14 thereby acoustically coupling the vibratory output of generator 12 to shaft 11. Impeller 9 is carried on the free end of shaft 11, and may be attached thereto by welding or other suitable means. Member 2 is provided with an opening 18 through which shaft 11 passes. The central wall portion of opening 18 is of such diameter as to tightly engage shaft 11 and thereby provide a fluid-tight seal. The central vertical plane of member 2, indicated at line 19 in FIGURES 1 and 2, passes through point 21 which is designed to substantially coincide with a velocity node when shaft 11 is vibrating at its resonant frequency. An elastic vibratory wave having a dimension as indicated at 32 will be imparted to shaft 11.

The spaces 22 and 23 located on either side of impeller 9 are filled with a liquid supplied via inlet pipes 24 and 25. Drain pipes 26 and 27 pass through the floor member 6 and provide a means for emptying the tank or for recirculating the liquid as may be required for a particular process. Wire baskets 28 and 29 are submerged in the liquid filling the tank and are designed to carry parts which are to be subjected to treatment. There is indicated at 31 a typical one of such parts to be treated. In operation of the apparatus, impeller 9 vibrates through a very short displacement distance towards and away from the inertial masses of the end members 1 and 2. Vibration generator 12 is preferably of the type disclosed in my copending application entitled Vibration Generator for Resonant Loads and Sonic Systems Embodying Same, filed Mar. 21, 1962, Ser. No. 181,385, now Patent No. 3,217,551.

Shaft 11 acts as a solid resonant member in acoustic coupling relationship with the output of sonic generator 12. The basic acoustic circuit consists of massive stationary end members 1 and 2, and massive impeller 9 activated sonically by the solid resonant elastic shaft 11. In the embodiment shown in FIGURES l and 2 the mass of the impeller is made to have a very high impedance output so as to be efiiciently matched to the fluid to which it is delivering energy. By this means cavitation can be controlled to a desirable degree, and optimum energy thus delivered to the fluid being treated, There is, however, no dependence upon the liquid in spaces 22 and 23 being a major part of the acoustic system. Thus, the invention is particularly desirable for those situations where the acoustic properties of the fluid itself are rather poor, or where the acoustic conditions of the fluid change during the chemical reaction. That is, the apparatus is independent of changes in conditions or of the sonic characteristics of the liquid being reacted. Being a high acoustic Q system, it is relatively independent of the acoustic prop erties of the medium being treated.

As indicated previously, sonic generator 12 may be of the orbiting mass type of oscillator. The orbiting mass type oscillator when coupled into an acoustic circuit having physical characteristics, tends to keep itself locked into the proper frequency and phase to maintain resonance in the circuit under these changing conditions. For example, in the application of the embodiment of the invention shown in FIGURES l and 2, the parts (e.g., 31) carried in baskets 28-29 may comprise porous solids which are to be impregnated with the liquid in the tank. Usually the internal structure of such porous solids has a very high damping coefficient, so that its acoustic energy absorption and resistive impedance increases during the period of impregnation. Under these conditions, the orbiting mass oscillator automatically shifts its phase so as to provide the power factor required to maintain a high level of energy introduction into the system as the resistive impedance increases relative to the reactive impedance. Also, as the porous solid becomes impregnated, very often its stiffness changes so that the reactive impedance at the contact point where the acoustic generator 12 is coupled, also tends to change. Here again, the important feature of the orbiting mass type oscillator is that it adapts itself to changes of the acoustic conditions. In addition, the part (31) very often changes its natural frequency, particularly when it is a substantial part of the resonating circuit. This change in frequency, involving a change in resonance, is also accommodated very effectively by the automatic self-adjusting characteristics of the orbiting mass type of sonic oscillator. It is important to note that acoustic conditions of a bath into which the part is submerged also change if the part is impregnated.

The part to be treated may be coupled directly to the sonic oscillator or may be acoustically coupled to an intermediate medium. In the above-described example, the sonic oscillator is coupled to the wave radiating surface of impeller which is in contact with the impregnation medium, so that the sonic energy is transmitted from the oscillator through the radiating surface, and then into the impregnating medium, and then on into the part being impregnated. This technique is especially effective where the process is employed on a high production basis involving the dipping or submergence of parts into a sonically activated impregnation medium. Appropriate modifications of this embodiment will suggest themselves to those versed in the art. For example, for batch treatment of large parts, such as putting insecticides into logs or large timbers, the sonic oscillator can be connected to the walls of a large autoclave container so that sonic energy is transmitted to the timber through the fluid of the autoclave. Another desirable variation is to connect the sonic oscillator directly to the log or the other member which is to be impregnated. This latter technique is especially effective where it is desired to give maximum sonic energy into the part being impregnated. It does not matter whether the orbiting mass type oscillator is connected di rectly to the part or is coupled to the fluid which is in contact with the part since in either event the orbiting mass oscillator changes its acoustic output phase angle to accommodate the change in conditions as the resistive impedance changes. This type of oscillator then accommodates itself so as to keep a good flow of power going into the workpiece during the whole cycle of impregnation.

There is shown in FIGURE 3 another embodiment of the invention which employs two massive members, between which liquid to be processed is circulated. One of the massive members functions as an inertia, and the opposing member functions as an impeller which is driven by an orbiting mass oscillator, with a resonant acoustic lever coupled therebetween. This combination gives a powerful, high Q system which is especially effective for sustaining a high level of cavitation, because the resonance is in the metallic structure, not in the liquid, as in devices of the prior art. This embodiment permits the delivery of two fluids within a reacting zone and the withdrawal of a third or reactive fluid therefrom. As can be seen in FIGURE 3, there is provided a cavity 33 in the wall of stationary member 34 and impeller 35 so that the fluids can be delivered to and extracted from the highly reactive zone therebetween. Member 34 serves as an enclosing wall of housing 36. Inlet passages 37 and 38 permit two separate liquids to be fed into the reaction zone defined by cavity 33. The reacted liquid is discharged through outlet passages 39 and 41. Impeller 35 is carried on one end of resonant bar 42. There is a slight clearance between the interior walls of housing 36 and the Opposing surfaces of impeller 35. This permits the liquid to fill all voids within housing 36.

Bar 42 extends though a receiving opening in one wall of housing 36 and is secured to the peripheral edge of this opening by means of sealing collar 43. The plane indicated by line 44 extends through a velocity antinode 45 of bar 42 in its resonant mode. Collar 43 is fastened to the exterior wall surface of housing 36 by any suitable means.

A torus shaped bladder 46 encircles bar 42 within housing 36. This bladder 46 is filled with a compressible fluid such as air and therefore is capable of expanding and contracting under the cyclical pressure variations produced within that portion of the interior of housing indicated at 47. This will absorb the pressure changes on one side of impeller 35 (viz. at 47) thereby confining the effective cyclical pressure changes to the area of cavity 33.

A suitable sonic generator 48 is acoustically coupled to the end of bar 42 opposite impeller 35, whereby a resonant standing wave (indicated at 49) is set up in the elastic material comprising bar 42. As in the previously described embodiment, the sonic generator 48 preferably comprises an orbiting mass type of oscillator.

In the embodiment shown in FIGURE 3, the elastic member (bar 42) has a wave pattern propagated therein such that the generator 48 can be at a relatively low impedance point (velocity antinode) of the wave pattern where vibratory motion is maximized for optimum power input, and the impeller reactance provides a high impedance region in the wave system so that the impeller moves with maximized force.

It has been found in the practice of the present invention that in fluid mixing phenomena, where acoustic cavitation is utilized, it is important that the vibratory surface, which radiates energy into the liquid, does not have too great a cyclic motion. If this cyclic excursion is too great, the radiator will lose its acoustic coupling with the liquid body, especially if the liquid body is confined between two high reactance solid structures. Moreover, it has been found that a liquid body contained over an extensive lateral area between two surfaces can accept very high cyclic forces, to create violent pressure changes.

Looking now at FIGURE 4, there is shown an embodiment in which the size of the treatment zone is reduced by bringing the stationary and movable members close together, thus concentrating the sonic energy over a small area. This embodiment comprises a pair of stationary members 51 and 52 which are secured to floor member 53 and which are joined at the top by cover member 54. The sides are enclosed by vertical walls (not shown) to provide a fluid-tight enclosure. Transverse I- beams 55 and 56 support floor member 53, and in turn are carried on frame 57. Impeller 58 is supported on one end of bar 59 for movement therewith in the direction of arrows 60. The opposite end of bar 59 is secured to the output of sonic generator 61. Bar 59 is supported at velocity node 64 by means of fluid-tight collar 63 which in turn is secured to stationary member 52. Generator 61 is carried on support 62, which in turn is mounted on frame 57.

Oscillator 61 is preferably an orbiting mass oscillator of the type referred to hereinabove in connection with FIGURES 1-3. It should be understood, however, that any suitabl means for imparting sonic energy of the required frequency and amplitude may be employed.

The plane indicated at 65 passes through velocity node 64 and the elastic wave pattern established in bar 59 is indicated at 66 and results in impeller 58 being driven at a velocity antinode. That is, the length and mounting point of bar 59 are designed in relation to one another to produce the desired resonant standing wave in bar 59, utilizing principles which are familiar to those skilled in the art. This standing wave is, in general, a half wavelength, in that it has velocity antinodes at either end and an intervening node. The wave pattern is modified however by location of th fixed mounting point (collar 63) which is somewhat closer to one end of the bar than the other, and by the large mass of impeller 58, so that its actual length is closer to wavelength.

Stationary member 51 is provided with a pair of inlet ducts 67 and 68, through which the fluid to be treated may pass, and a plurality of outlet ducts 69-72. This arrangement requires that the fluid to be treated must pass through the restricted area between the impeller 58 and stationary members 51 and 52 before it can pass through the outlet ducts 6972. This embodiment is particularly useful for homogenization and emulsification and the disintegration of agglomerates. The standing wave patterns obtained is diagrammed at 66, with the vertical height of the pattern at any point along its length being representative of both the amplitude and velocity of the longitudinal vibration at corresponding points of the acoustic system. As will be understood by those versed in the art, and is evident from the standing wave pattern diagrammed at 66 in FIGURE 4, the amplitude of the longitudinal vibration at the mounting point of bar 59 is substantially zero affording the aforementioned node. The two portions of the elastic bar 59 either side of node 64 elastically elongate and contact in unison with one another in the establishment of the standing wave pattern. As will further be evident, the amplitude of the vibratory motion is considerably larger at the generator end (61) of the bar 59 than it is at the impeller 58. correspondingly, the cyclic force exerted by the impeller 58 on the fluid entering through ducts 67 and 68 is proportionally multiplied over the cyclic force exerted by the generator 61 on the generator end of the bar 59. At the same time, the velocity, or displacement amplitude, of the large inertia mass of impeller 58 is relatively low. Fluid in the area between the inertia mass of impeller 58 and members 51 and 52 is thus subjected to a cyclic stress of high magnitude, but with displacement amplitude and velocity of a very low magnitude. The condition at both impeller 58 and within the fluid between the impeller 58 and members 51 and 52 is thus one of high acoustic impedance. Under these conditions, the fluid undergoes an alternating compressional and tensional wave, with the magnitude of cyclic tension materially exceeding the endurance limit of the liquid, so that cavitation occurs. The desirable high acoustic impedance at the impeller 58 is desirable for good impedance match to the liquid. The desirable high impedance is attained by using an impeller of high inertia mass, and therefore high mass reactance. By providing for a mass reactance which is large as compared with the resistive vector component of the impedance (which resistive component is of course owing to frictional dissipation of energy in the system) the Q factor of the vibratory system is desirably high. The factor Q will of course be understood to be either a figure of merit of vibratory systems, measured either by the ratio of the reactive component of impedance to the resistive component thereof, or by the ratio of energy stored to energy expended per cycle of operation. The system is characterized by desirable low impedance at the generator end (61), and desirable high impedance at the liquid mixing end (58), with the intervening elastically vibratory bar 59' functioning as an acoustic lever, or may be considered as an impedance adjusting transformer. Accordingly, it is clear that a suitably high Q is easily achieved by the simple expedient of choosing materials, masses and dimensions for the essential components of this invention, in accordance with the definitions and formulas given and discussed hereinabove. Thus, all parameters necessary for a high Q system are easily predetermined for the size system desired.

While the node end of bar 59 is shown in FIGURE 4 as located approximately 25% of the length of the bar from the impeller 58, it can, in practice, be considerably closer, with desirably further increased output impedance. Impeller 58 may thus have its amplitude of vibration reduced to a very small magnitude. The total length of the standing wave is then quite close to the quarter wavelength, and from a practical standpoint, the standing wave may be said to be approximately a quarter wavelength long. Even in such case, however, the standing wave system comprises two velocity antinodes and an intervening node so that, while the actual distance from the output antinode to the mounting node may be quite small, the standing wave is in the nature of a half-wave system in the sense that it has opposed motion at its ends, and an intervening node. It should be understood that harmonic frequency standing waves may be generated in lieu of, or in addition to, the fundamental wave shown and such modification is considered to be within the scope of the invention.

While a skid type base is shown in the embodiment of FIGURE 4, it should be understood that this is not restrictive and any suitable arrangement may be employed.

Since the structure of the invention comprises a vibrating system exhibiting resonant phenomena, an explanation of the invention may be facilitated by employing a dynamical analogy between a mechanical vibrating system and an electrical network excited by an alternating current. This type of analogy is well known to those versed in the art and is described, for example, in Dynamical Analogies published in 1943 by D. Van Nostrans Co., N.Y., and in Chapter 2 of Sonics by Hueter and Bolt, published in 1955 by John Wiley & Son. Due to the Widespread familiarity which engineers have of the characteristics and designs of electrical circuits, the relationships and functions of the elements comprising the mechanical vibrating system of the present invention may be more easily visualized and analyzed by means of an equivalent circuit. There is shown in FIGURE 5 a simplified electrical network which is a dynamical analogy of the structure shown in FIGURE 1. It should be noted that in the mechanical system the forces acting on the mass are in parallel, while in the electrical system the components of the system are in series. If the forces in the mechanical system were in series, then the equivalent electrical system would be put in parallel.

Referring now to FIGURE 5, there is shown a circuit diagram which is analogous to the basic structure of the apparatus of the invention, as particularly exemplified by the embodiments of FIGURES 3 and 4. Generator 74 corresponds to the sonic oscillator 48 of FIGURE 3 or 61 of FIGURE 4. The resonant circuit comprises shunt capacitance 75, series resistor 77, and inductance 76. Resistance 78 corresponds to the load resistance of the fluid to be treated and as can be seen is isolated from the tuned circuit. That is, the acoustic load is purely resistive. Inductance 76 corresponds to the mass of the impeller 35 of FIGURE 3 or 58 of FIGURE 4. The elastic compliance of bar 42 (or 59) is the equivalent of capacitance 75. Resistance 77 corresponds to frictional losses in the system.

In connection with the resonant phenomenon, it is important to note that resonance includes capacitance, inductance, and usually in any practical system it also employs resistance. However, the main factors determining the resonant frequency in the present system is the inductance (76) and capacitance (75) combination of the circuit. Therefore, in a practical application of the invention it is preferred to set up the arrangement in such a 10 way that either the moving block (e.g., impeller 9, 35, or 58) or the fixed inertial masses (e.g., members 1, 2, 34, 51, 52) function as a major portion of either the capacitance or the inductance of the resonant circuit. It is important to note that the fluid in the tank is an essential part of the termination region.

From the foregoing description of the embodiments of FIGURES 3 and 4 it will be seen that an advantage of the apparatus of the present invention is that the fluid to be treated can be maintained in a small total volume in the treatment area, with a reasonably high fluid transfer rate so that there can be a controllably small resonance time of the fluid in the acoustic circuit. This latter function is especially desirable in many chemical reactions where it is desired to arrest a chemical reaction at some intermediate state of a chain reaction or other multi-stage, chemical, step-type, process. In other words, it is possible by the present invention to accurately control the resonance time of the reacting fluid down to a very minimum of time Within the acoustic environment.

In all embodiments of the invention, it is preferred that a large cyclic force and small cyclic motion be generated by the impeller. This double function is ideally accomplished by the apparatus of the present invention wherein the impeller is located at a fairly high impedance region in the elastic resonant system. This impedance transformation can be accomplished by a lumped constant system which is somewhat equivalent to the above-described wave pattern system. In the lumped constant system the elastic bar functions more as a pure capacitance, its mass not being very important, and the opposed inductive reactances being provided by the heavier impeller mass and the lighter mass of the oscillator housing. This ratio of two diiferent mass values is in inverse ratio values, or amounts, of the respective motions of the two masses, However, in actual practice, the elastic member is usually a fairly strongly built element such that its distributed mass is in fact in the circuit, and the partial wave pattern effect usually exists with a combined distributed-constant and lumped-constant system.

It should also be recognized that the oscillator may be located at the high impedance region, relying only upon the bar and some other associated mass for the opposed phase motion. This, however, usually does not give 0ptimized power output from the oscillator. Ordinarily, the oscillator operates most efiiciently when located at a lower impedance region, where the current (motion) is higher, so as to better utilize its given voltage (cyclic force) output.

Summarizing, the sonic resonant system comprises a capacitance between two inductances even though one of the inductances might be only the distributed inductance of the elastic member.

The use to which the present invention is put actually forms no part of the invention and the typical uses mentioned hereinabove merely illustrate the operation of the invention. It will, however, be obvious to those versed in the art that many additional uses exist including the cracking of molecules in various chemical processes, juice extraction from food materials, and other processing of foods such as removing meat from the bone where raw stock is cooked in the making of soups, etc. Also, in the foregoing description, it will be evident that each of the embodiments described accomplish the objectives preliminarily stated, and embody various features of advantage described in the introductory portion of the specification.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to preferred embodiments, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated and in their operation may be made by those skilled in the art, without departing from the spirit of the invention; therefore, it is intended that the invention be limited only as indicated by the scope of the following claims.

What is claimed is:

1. A resonant system for treating a fluid by producing cavitation therein by coupled acoustic energy, comprising: an enclosure for containing the fluid to be treated;

.a resonant circuit comprising a mechanical cyclical force generator, an impeller and an elastic driving member;

said mechanical cyclical force generator having a given source impedance at the natural frequency of said resonant circuit;

said impeller member having a mass reactance at said natural frequency which is substantially higher in value than the source impedance of said generator, and being movably mounted within said enclosure and adapted to contact said fluid to be treated; and

a stationary member, having a mass reactance at said natural frequency which is substantially higher in value than the source impedance of said generator, spaced apart from and in confronting relationship with said impeller member;

said elastic member drivingly coupling said force generator and said impeller member for imparting acoustic energy at resonance to said fluid to be treated, said elastic member having a resonant standing wave imparted thereto by said force generator and having an elastic compliance reactance of a value which increases the Q of said circuit by transforming the low impedance presented to said elastic member by said force generator to the high impedance presented to said elastic member by said impeller member.

. A resonant system as defined in claim 1 including:

a second stationary member, having a mass reactance at said natural frequency which is substantially higher in value than the source impedance of said generator, spaced apart from said impeller member and having an aperture therethrough, through which said elastic member extends, thus permitting said second stationary member to be in confrontation with said impeller member opposite said first-mentioned stationary member.

3. Liquid treatment apparatus employing cavitation induced by means of sonic wave action, comprising:

an acoustically inductive impeller having a given inductive reactance, in contact with a liquid to be treated;

a sonic wave generator, having an inductive reactance which is lower than said given inductive reactance of said impeller, for providing acoustic energy; and

:an elastically vibratory acoustic energy transmission member drivingly coupled between said generator and said impeller whereby a Standing wave is imparted to said member by said generator and having a capacitive reactance of a value which will cause said liquid to present a substantially resistive impedance to said impeller when being driven by said generator through said member.

4. Liquid treatment apparatus as defined in claim 3 including:

means for maintaining said acoustic energy at a frequency which will cause resonant vibration in the system comprising said impeller, said generator, and said transmission member.

5. Liquid treatment apparatus as defined in claim 3 wherein said generator is responsive to changes in the ratio between the resistive impedance of said liquid and said inductive reactance to maintain resonant vibration in the system comprising said impeller, said generator, and said transmission member.

6. Liquid treatment apparatus with sonic wave action comprising:

a pair of opposed, acoustic inductance members between which a fluid to be treated may circulate, and at least one of which is vibratorily movable towards and away from the other;

a sonic wave generator for providing an alternating out put force; and

an elastically vibratory wave transmission element comprising a member of solid elastic material dr'ivingly coupled between said generator and said movable inductance member so as to transmit said alternating force from said generator to said vibratorily movable member. i

7. Liquid treatment apparatus as defined in claim 6 wherein:

said elastically vibratory wave transmission element comprises an elongated longitudinally elastically vibratory bar coupledat one end to said sonic wave generator, and at its other end to said vibratorily movable member; and including i means operating said sonic wave generator at a resonant longitudinal standing wave frequency for the acoustic system comprised of said vibratorily movable member, said bar, and said sonic wave generator.

8. Liquid treatment apparatus as defined in claim 6 wherein:

said elastically vibratory transmission element comprises an elongated longitudinally elastically vibratory structure coupled at one end to said sonic wave generator and at its other end to said vibratorily movable member; and including support means located at a stationary nodal point of said elongated structure, said nodal point being'at a point substantially nearer the end of such structure coupled to said vibratorily movable member than to the end of said structure coupled to said sonic Wave generator; and

means operating said sonic wave generator at =a resonant longitudinal standing Wave frequency for the acoustic system comprised of said vibratorily movable member, said elongated vibratory structure, and said wave generator.

9. Liquid treatment apparatus as defined in claim 6 wherein the other member and said vibratorily movable member are horizontally opposed to one another, with a space for the liquid to be treated therebetween, and said vibratorily movable member is movable with a horizontal component of vibration, and said elastically vibratory transmission element comprises:

a generally horizontally elongated longitudinal vibratory structure coupled at one end to said sonic wave generator, and at its other end to said vibratorily movable member;

support means located at a stationary nodal point of said elongated structure, said nodal point being at a point substantially nearer its end coupled to said vibratorily movable member than to its end coupled to said sonic wave generator; and

means operating said sonic wave generator at a resonant longitudinal standing wave frequency for the acoustic system comprised of said vibratorily movable member, said elongated vibratory structure, and said sonic wave generator.

10. Liquid treatment apparatus as defined in claim 6 wherein the elastically vibratory wave transmission system is characterized by an acoustic impedance at the coupling between said transmission member and said sonic wave generator which is substantially higher than the acoustic impedance at the coupling between said transmission member and said vibratorily movable member, whereby a relatively high vibration amplitude and a low cyclical force at said generator is transformed into a relatively low vibration amplitude and high cyclical force at said movable member.

11. A resonant system for treating a fluid by producing cavitation therein by coupled acoustic energy, comprising:

means for confining the fluid to be treated;

a resonant circuit comprising a source of acoustic energy, a vibrating acoustic inductance member and an acoustic capacitance member;

said source of vibratory acoustic energy being adjustable to the natural frequency of said resonant circuit 13 and having a given source impedance at said natural frequency;

a stationary acoustic inductance member in contact with the fluid in said confining means and having an acoustic impedance which is substantially higher in value than the source impedance of said acoustic energy source;

said vibratory acoustic inductance member being spaced apart from and out of phase with said stationary member and having an acoustic impedance which is substantially higher in value than said source impedance, said vibratory member being in contact With said fluid; and

said acoustic capacitance member being drivingly coupled between said source and said vibratory member and having a standing wave imparted thereto by said source of acoustic energy and having an acoustic capacitance which is sufiicient to substantially match said source impedance to the acoustic impedance of said vibratory member.

14 1 References Cited UNITED STATES PATENTS 3/ 1944 Bechmann et al. 11/1966 Bodine 241-38 12/1929 Claypoole 259-1 X 11/ 1938 Williams 259- 1 5/1951 Horsley et a1. 259-1 7/1959 Faidley 259-1 5/1964 Bodine.

6/1965 Bodine 259-1 2/1966 Bouyoucos 259-4 FOREIGN PATENTS 3/1930 Great Britain.

WALTER A. SCHEEL, Primary Examiner.

J. M. BELL, Assistant Examiner.

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