US3464672A - Sonic processing transducer - Google Patents

Description

Sept. 2, 1969 F. MASSA SONIC PROCESSING TRANSDUCER 2 Sheets-Sheet 1 Filed Oct. 26, 1966 wmufff f 4 u. RA 11C f m V Kv MM R,

Sept. 2, 1969 F. MASSA 3,464,672

SONIC PROCESSING TRANSDUCER Filed Oct. 26, 1966 2 Sheets-Sheet 2 FRANK MASS/1 INVENTOR.

United States Patent O 3,464,672 SONIC PROCESSING TRANSDUCER Frank Massa, Cohasset, Mass., assignor to Massa Division, Dynamics Corporation of America, Hingham, Mass.

Filed Oct. 26, 1966, Ser. No. 589,665 Int. Cl. B01f 11/02; B28c 5/08 US. Cl. 259-1 22 Claims ABSTRACT OF THE DISCLOSURE The invention provides a sonic processing system having several embodiments. An especially useful feature common to all embodiments is the use of one or more cylindrical piezoelectric transducers bonded to the inside or outside of a pliable tubular housing. This way, the flexibility of the pliable housing compensates for any manufacturing variations, thus eliminating the need for final machining to size and allowing for the use of wide manufacturing tolerances. The various embodiments feature discrete containers for batch processing and tubular containers for continuous processing.

This invention relates to sonic processing transducers which generate vibrations by the radial oscillation of cylindrical shells and more particularly with an economical high power sonic processing system containing polarized, ceramic tubular shell transducers made from materials such as lead zirconate titanate. Although this invention is particularly advantageous for cylindrical or tubular ceramic shell transducers because it nullifies the adverse effects of out-of-roundness deviations that occur in manufacturing ceramic cylinders or tubes and avoids the necessity for expensive grinding of fired elements, it is equally applicable to magnetostrictive vibrators.

A primary object of this invention is to provide an economical, cylindrical, sonic processing transducer in which radially vibrating cylindrical shells are bonded to the surface of a flexible, rubber-like, cylindrical tube; the pliable tubing being capable of deformation so that any irregularities in the contour of the transducer shells will be compensated for by the pliable wall.

Another object of this invention is to provide an efficient, low cost, sonic processing system in which a cupshaped container is excited by radial vibrations through its cylindrical surface so that concentrated sonic energy is produced within a liquid that may be placed inside the container.

A still further object of this invention is to provide a continuous, flexible tubular transducer assembly in which sonic vibrations are transmitted through the wall of a flexible tube by means of cylindrical or tubular ceramic shell transducer elements bonded to the periphery of the flexible tube.

Another object of this invention is to provide a flexible, tubular sonic processing transducer through which a fluid may be transmitted for continuous, sonic processing.

Another object of this invention is to provide a composite, flexible, hose-like structure having an inner chamher through which a fluid may be transmitted for sonic processing and in which the hose-like transducer includes an outer protective surface which is spaced from the tubular transducer elements which are bonded to the outer periphery of the inner tube.

A further object of the invention is to provide means for circulating a fluid coolant through the space between the ceramic elements and the outer jacket for dissipating heat generated during high power operation.

A still further object of this invention is to provide a flexible hose-like, sonic transducer suitable for continuous sonic processing of a liquid which is passed through a 3,464,672- Patented Sept. 2, 1969 concentric annular chamber between an outer pliable tube and an inner concentric pliable tube wherein the transducer comprises tubular ceramic shells which are bonded to the inner periphery of the inside concentric tube and capable of being excited in a radial mode of vibration.

An additional object of this invention is to provide means for continuous sonic processing of a fluid by passing the fluid through a relatively long hose-like structure into which sonic vibrations are transmitted by a plurality of radially vibrating tubular shells attached to the peripheral wall of the hose-like structure.

The novel features which are characteristic of this invention are set forth with particularity in the appended claims; however, the organization, method of operation, and advantages of the invention will be understood best from the following description of several embodiments illustrated in the accompanying drawings in which:

FIGURE 1 is a vertical cross-sectional view of a transducer constructed according to this invention containing a flexible, tubular cup-like container mounted at the top of a cylindrically shaped, plastic housing, a single ceramic ring transducer element mounted on the container, and an electronic power supply for energizing the transducer;

FIGURE 2 is a partial vertical section illustrating a modification of the transducer of FIGURE 1 containing a deeper flexible cylindrical container and three ceramic ring transducer elements bonded to the periphery of the tank for increasing the capacity of the sonic processing unit; 7

FIGURE 3 is an axial sectional view of a long tubular sonic processing transducer embodying another form of the invention;

FIGURE 4 is a view taken along the section line 4-4 of FIGURE 3.

FIGURE 5 is an axial sectional view showing a modified form of this invention incorporated in a tubular transducer in which sonic vibrations are generated in the annular space between two concentric tubular elements;

FIGURE 6 is a view taken along the section line 66 of FIGURE 5;

FIGURE 7 illustrates a continuous sonic processing installation making use of a long section of a coiled tubular transducer constructed according to this invention; and

FIGURE 8 illustrates another application of a tubular sonic processing transducer of this invention in which a batch of liquid may be circulated through the transducer for an extended period of time.

Referring more particularly to the figures in which the same reference characters will be used to identify similar elements, FIGURE 1 illustrates a portable sonic processing unit incorporating a cylindrical or tubular container 10 which may be made of a molded, rubber-like substance for holding the material to be sonically processed. To the outer surface of the container 10, is bonded a tubular transducer element 12 which may comprise a polarized, piezoelectric ceramic ring of a material such as barium titanate, lead zirconate titanate, or any other similar material which is capable of being excited into radial vibration, sometimes referred to in the art as the circumferential mode of vibration, by the application of an alternating voltage to its electrodes such as the electrodes 14 and 16.

In the illustrated example, the ceramic element 12 is provided with an outer cylindrical electrode 16 and an inner cylindrical electrode 14. These electrodes are used for polarizing the ceramic element during its manufacture in the conventional manner. The inner surface of the ceramic ring 12 is bonded to the outer wall of the container 10 by a suitable layer of cement 18'which may be an epoxy film or other suitable adhesive.

Of special importance in the economical manufacture of the transducer assembly is the fact that the container is pliable and has outer walls which may be deformed easily to fit the exact contour of the ceramic ring 12. Because of this, the ceramic rings need not 'be ground to precise dimensions to achieve a secure mechanical contact through the cement layer 18.

A further advantage of using a rubber-like material, such as polybutadiene, for forming the cup is that the container 10 remains remarkably free of defects which are caused by cavitation at the container surfaces during operation. Such a transducer is more durable than one comprising a metal cup.

To achieve a reliable bond between the outer wall of container 10 and the inner surface of the ceramic ring 12, a tool, such as a thick rubber cylinder which may be placed within the opening of the container 10 and squeezed by means such as a mechanical clamp so that outward radial pressure is exerted on the inside wall of the container 10 to deform the wall into the exact contour of the inner surface of the ceramic ring 12, may be used. When the bonding is completed, the pressure tool is re moved and perfect acoustical coupling is achieved at low cost without machining the inside surface of the ceramic cylinder. Prior to bonding the ceramic element 12 to the wall of container 10, electrical conductors 20 and 22 are soldered respectively to the electrode surfaces 14 and 16.

If desired, the fundamental advantages of this invention can be secured with other transducer elements such as a laminated, magnetostrictive metal alloy shell, of a material such as nickel, having a suitable toroidal excitation winding.

The combination of the ceramic tube or ring 12 and the pliable container 10 forms the basic transducer structure. FIGURE 1 illustrates how the transducer assembly may be combined with a housing and electronic power supply to form a complete sonic processing unit which is portable.

The container 10 may be molded with a flange-like periphery 26 which may be sealed to the open end of a housing such as molded plastic cylinder 28. Near the opposite internal opening of the housing 28, several bosses 30 may be placed to serve as mounting surfaces. A base plate 32 may be fastened to the bosses 30 by screws. The base plate 32 supports electronic oscillator and power supply 34, which may comprise conventional circuitry.

The conductors 20 and 22 are connected to output terminals 36 and 38 of the power supply 34. A power cord 40, which may be supported by a grommet 4'4 molded near its end has two insulated conductors 46 and 48 which are soldered to the terminals 52 and 54 of the power supply 34. Near the bottom open end of the housing 28, a closure plate 60 may be fastened to bosses 62 by means of the screws to complete the assembly of the transducer. Molded rubber feet 66 may be inserted in the periphery of closure plate 60, as illustrated, to serve as a support.

When the electrical power supply is activated and the ceramic ring 12 is driven at its radial mode resonant frequency, intense sonic energy will be transmitted into liquid 70 within container 10.

FIGURE 2 illustrates a modification of the transducer of FIGURE 1 in which the tubular container 10 is made deeper. Instead of a single ring, several polarized ceramic rings 12 are bonded to the wall of container 10 described in connection with FIGURE 1. The inside electrodes 14 of the rings 12 are interconnected by conductors 80. The outside electrodes 16 of the rings are connected by means of the conductors 82. The parallel connected ceramic elements 12 are connected to an electronic power supply (not shown) by conductors 20 and 22.

Except for the deeper container 10 and the use of multiple transducer elements 12, the construction of the transducer of FIGURE 2 is identical to that of FIG- URE 1.

It is advantageous to make the axial width of the ceramic rings 12 less than the largest radial dimension,

the largest dimension in the direction orthogonal to the axis of the tube such as the diameter of the rings where circular rings are used, because in relatively wide rings, the radial resonant mode of vibration of the rings is aifected by the longitudinal resonant mode of vibration.

FIGURES 3 and 4 illustrate a section of a tubular conduit which incorporates another form of a transducer of this invention which is useful for the continuous sonic processing of liquids. In this embodiment a long (measured in feet) flexible tube 90, which may be made of a rubber-like material such as polybutadiene which resists cavitation deterioration, has a number of ceramic rings 12 bonded to its outer surface in a manner similar to that which was described previously. The electrodes 14 on the inner surface of the ceramic rings 12 are connected together by flexible conductors prior to the bonding of the electrode surfaces to the outer periphery of the flexible tube by'the cement layer.

An inexpensive method of bonding a number of elements to the outer surface of the tube 90 comprises pumping air into the opening of the tube 90 to cause the flexible walls to expand and to make complete contact to the inner surfaces of the rings 12. The outer wall of the tube 90 conforms to the various irregularities and deviations that occur in the inner peripheral dimensions of the ceramic rings 12. The tube 90 is pressurized until the cement 18 is completely cured.

After completing the bonding of the ceramic rings 12 to the tube 90, the outer electrodes 16 are connected in parallel by the flexible leads 82 as illustrated.

The external housing of the assembly comprises a flexible, extruded tube 92 having a number of internal spacing ribs 94 for supporting the tube 92 in generally concentric relation around tube 90 as shown in FIGURE 3. When the tube 92 is assembled as an outer jacket over the outside periphery of the rings 12, an annular space or chamber remains between the inner wall of the tube 92 and the outer surfaces of the ceramic rings 12. This annular space forms a continuous air duct along the length of the transducer assembly through which air or another fluid can be supplied to cool the transducer during high power operation or to regulate the temperature of the fluid being processed.

The liquid to be sonically processed is pumped through the tube 90. When the ceramic rings 12 are electrically energized, sonic vibrations generated by the rings are transmitted directly to the liquid within the tube 90.

Because the tubes 90 and 92 are flexible and the ceramic rings 12 are spaced apart and connected by flexible leads, the tubular transducer can be bent, twisted or coiled as operating conditions require, thereby facilitating the storage of long lengths of the tubular transducer in relatively small and confined spaces.

A variation of the flexible tubular transducer described in FIGURES 3 and 4 is illustrated in FIGURES 5 and 6. In this embodiment, the inner wall surface of a flexible tube is bonded to the outer peripheries of the electrodes 14 and outer electrodes 16 are connected respectively in parallel by electric conductors 80 and 82. After the assembled group of cement coated ceramic rings 12 are placed inside the cement coated tube 100, radical pressure is exerted against the outer surface of flexible tube 100 to insure bonding between the rings 12 and the tube 100. The radial pressure may be applied by any number of methods such as the wrapping of the tube 100 with rubber tape stretched over its outer surface. An outer, flexible extruded tube 102, which may have internal spacing ribs 104, surrounds the tube 100 and serves as the housing of the sonic processing transducer. Because of the presence of the ribs 104, a peripheral chamber 106 is provided through which a liquid may be passed for sonic processing. Center chamher 110 which passes through the rings 12 may be used as a duct for a fluid which regulates the transducer temperature so that the optimum processing temperature may be maintained.

The basic function of both the transducer structures described in FIGURES 3 and 4 and FIGURES 5 and 6 is the same; namely, the sonic processing of liquids during their passage through a long continuous duct. The transducer illustrated in FIGURES 3 and 4 concentrates energy into a central chamber, whereas the embodiment illustrated in FIGURES 5 and 6 distributes sonic energy in a peripheral chamber which, for a given size of transducer ring 12, provides a greater cross-sectional area of chamber for sonic processing than can be obtained with a transducer having a central processing chamber. The structure shown in FIGURES 5 and 6 may be preferred for certain types of industrial processing in which high rates of fluid flow are desired within a transducer of a minimum size.

For reasons previously described, optimal performance is achieved when the width of the ceramic rings 12 does not exceed the largest radial dimension, such as the diameter of the rings. This limitation is important for another reason; namely, a more flexible tube is obtainable with narrow rings than would be the case if wide rings were used.

The tubular transducers may be made in standard, modular lengths and provided with suitable end connections to permit coupling of any number of modules together to produce a total length of flexible transducer of any desired dimension. It is further possible to design each modular length of transducer so that it is operated by a separate electronic power supply; thereby increasing the reliability of the complete sonic processing system by providing redundancy.

FIGURE 7 illustrates one embodiment of the invention combined in a continuous sonic processing system. Container 120 serves as a reservoir for the product which is to be sonically activated. A helically coiled length of tubular transducer 122 is fabricated from a number of modules of tubular transducer sections, as described above in FIGURES 3-6. The total length of the coiled transducer 122 is determined by the rate of flow of the liquid to be processed and the amount of time that the material is to be exposed to the sonic vibration. A valve 124 having 'an outlet 126 is connected to the free end of the transducer 122.

To use the continuous sonic processing system shown in FIGURE 7, the ingredients to be processed are poured into the container 120 and the valve is adjusted to regulate the desired rate of flow through the coiled transducer. During the flow of the material through the tubular transducer, the transducer elements are energized by their power supplies to cause continuous sonic processing of the material flowing through the coiled transducer 122.

A batch processing system incorporating a tubular transducer is illustrated in FIGURE 8. A suitable container 130 is provided for holding a quantity of material which is to be sonically processed. A length of tubular transducer comprising sections 134 and 136 is connected between a drain tube 140 located near the bottom of the tank and a fill tube 142 located near the top of the tank. A pump 144 is connected in series with the tubular transducer sections 134 and 136. The pump .144 circulates the liquid 132 through the system so that it will be continuously passed through the loop formed by the tubular transducer for whatever period of time is required to achieve the desired results from the sonic processing.

While there have been shown and described several specific illustrative embodiments of the present invention, it will, of course, be understood that various modifications and alternative constructions may be made without departing from the true spirit and scope of the invention. Therefore the appended claims are intended to cover all such modifications and alternative constructions as fall within their true spirit and scope.

What is claimed is:

1. A sonic processing appliance comprising a transducer element capable of vibrational excitation in a circumferential mode, said transducer having a generally tubular shape with inner and outer peripheral walls, a container having a flexible tubular wall, the outer peripheral wall of said flexible container having approximately the same peripheral dimensions as the inner pe ripheral wall of said tubular transducer element, and means for bonding said inner Wall surface of said trans ducer element to said outer wall surface of said flexible tubular container.

2. The sonic processing appliance of claim 1 wherein the transducer element is a piezoelectric transducer element.

3. The sonic processing appliance of claim 1 wherein the transducer element is a magnetostrictive transducer element.

4. The sonic processing appliance of claim 1 wherein said transducer element is a cylindrical shell, and wherein the axial length of the shell does not exceed the outside diameter of the shell.

5. The sonic processing appliance of claim 1 comprising in addition: a rigid housing having an open end; and a flange secured to the open end of the housing; and wherein the tubular container is supported at one end by the flange and the other end of the tubular container is sealed to form a cup.

6. The sonic processing appliance of claim 5 wherein the flange and the tubular container are of an integral, seamless construction.

7. The sonic processing appliance of claim 5 comprising in addition: means, secured to the interior of the housing, for energizing the transducer elements.

8. A sonic processing appliance comprising a rigid walled housing having an open end, a flexible walled cylindrical cup-shaped container having an extended flange portion at its open end, said extended flange portion being shaped for mounting upon and forming a closure over the open end of said rigid housing, a plurality of transducer elements each having a cylindrical tubular shape capable of vibrational excitation in a circumferential mode, each transducer having inner and outer peripheral walls, and means for bonding the inner peripheral walls of each of said plurality of transducer elements to the outer peripheral wall of said flexible cupshaped container.

9. The appliance of claim 8 wherein the axial length of each of said cylindrical transducer elements does not exceed the outer diameters of said cylindrical elements.

10. The appliance of claim 8 comprising in addition: means, secured to the inside of the housing, for energizing the transducer elements.

11. A sonic processing transducer comprising a flexible tubular conduit having an inner and outer wall surface, a plurality of transducer elements, each of said elements having a tubular shape with inner and outer wall surfaces, and means for bonding the inner wall surfaces of each of said plurality of said transducer elements to the outer wall surface of said flexible tubular conduit.

12. The invention set forth in claim 11 wherein both said tubular conduit and said tubular transducer elements are cylindrical in shape, the axial length of said transducer elements being less than the outer diameter of said elements.

13. The sonic processing transducer of claim 12 comprising in addition: a second flexible tubular conduit having an inner diameter which is greater than the outer diameters of the transducer elements, said second conduit forming an enclosed housing around the transducer elements; and means for supporting the second tubular conduit in generally concentric relation with the first tubular conduit.

14. The sonic processing transducer of claim 13 wherein a chamber is formed between the first and second tubular conduits.

15. A sonic processing transducer comprising first and second flexible tubular conduits, each of said conduits having inner and outer cylindrical wall surfaces, a plurality of cylindrical transducer elements, each of said elements having inner and outer wall surfaces, means for bonding the outer surfaces of said transducer elements to the inner wall of a first of said flexible tubular conduits, the second of said cylindrical tubular conduits coaxially surrounding said first tubular conduit, and longitudinal spacing means between the outer surface of said first conduit and the inner surface of said second conduit whereby an annular duct is provided between said first and second conduits.

16. The sonic processing transducer of claim 15 wherein the axial length of each transducer element is less than its outside diameter.

17. A continuous sonic processing system comprising:

(a) a tubular sonic transducer containing (i) a flexible wall defining a chamber through which fluid to be sonically processed may flow, and

(ii) cylindrical transducer means bonded to said flexible wall for transmitting sonic vibrations through the wall into the chamber; and

(b) means for circulating the fluid through the chamber at a controlled rate of flow.

18. The continuous sonic processing system of claim 17 comprising in addition:

a container in fluid communication with the tubular sonic transducer, for holding the fluid to be processed; and wherein the tubular sonic transducer is coiled.

19. The continuous sonic processing system of claim 17 comprising in addition:

a container, for holding the fluid to be processed, having a fill tube for filling the container with fluid and a drain tube for draining the container of fluid; and wherein one end of the tubular sonic processing transducer is connected to the fill tube and the other end of the tubular sonic processing transducer is connected to the drain tube. 20. A sonic processing transducer comprising: (a) a tubular, rigid-walled housing having an open end and a closed end, the closed end forming a base for supporting the housing in a position such that its axis is generally perpendicular to the plane of a surface supporting the transducer;

(b) a cup-shaped container of pliable material, the container having a peripheral wall portion generally parallel with the axis of the cup-shaped container and an extended flange portion located at the open end of the container, the plane of the flange being generally transverse to the axis of the container;

(c) means for securing the flange to the open end of the housing to form a cover for the housing and to support the container within the housing;

(d) a tubular transducer element, capable of vibration in a radial mode, having an inner wall and an outer wall;

(e) means for bonding the inner wall of the transducer element to the outer surface of the peripheral wall portion of the container; and

(f) means, secured to the inside of the housing, for energizing the transducer element.

21. The sonic processing transducer of claim 20 wherethe transducer element is a polarized, ceramic shell of piezoelectric material.

22. The sonic processing transducer of claim 20 comprising:

a plurality of tubular transducer elements capable of vibration in a radial mode, the elements being bonded at their inner walls to the outer surface of the peripheral wall portion of the container.

References Cited UNITED STATES PATENTS 2,407,462 9/1946 Whiteley. 2,578,505 12/1951 Carlin. 2,585,103 2/1952 Fitzgerald. 3,021,120 2/1962 Van der Burgt. 3,056,589 10/ 1962 Daniel. 3,165,299 1/ 1965 Balamuth et 21. 3,180,626 4/1965 Mettler 2591 XR 3,194,640 7/1965 Nesh 259-1 XR 3,195,586 7/1965 Vogt 2594 XR WALTER A. SCHEEL, Primary Examiner JOHN M. BELL, Assistant Examiner US. Cl. X.R. 2592, 4, 72

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