Acoustic Transducer System

Abstract

The system includes a support, typically part of a dishwasher or clothes washing machine, having a plurality of piezoelectric transducers. Each piezoelectric transducer may have a cylindrical housing with a water inlet along the side of the housing. The piezoelectric transducer also includes a lens and a piezoelectric material having electrodes configured to couple to a power source.

Description

[Background technology]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This PCT application claims the benefit of U.S. Provisional Patent Application No. 62 / 954,842, filed December 30, 2019, and entitled “Acoustic Transducer System,” the contents of which are incorporated by reference in their entirety.

[0002] Current dishwashers operate by spraying warm water onto the dishes and utensils contained therein. During the wash cycle, the water is mixed with dishwasher detergent and pumped to one or more rotating spray arms, which then spray the dishes with the cleaning mixture. During the rinse cycle, the process is repeated using purified water, which may be mixed with a rinse aid to prevent droplet formation, thus reducing hard water water spots. However, current dishwashers have drawbacks.

[0003] Current clothes washing machines also operate in a similar manner, using a combination of mechanical tumbling motion and agitated pumped water to wash clothes.Current clothes washing machines have drawbacks.

[0004] The present invention relates to a system, which is particularly useful for dishwashing and laundry washing. Summary of the Invention

[0005] The present invention overcomes the shortcomings of the prior art. In particular, the system according to the present invention includes at least one support and a plurality of piezoelectric transducers supported by the support. Each piezoelectric transducer may include a cylindrical housing having a cylindrical side, a closed bottom, and a conical or pyramidal top, with a drainage outlet centered along the top of the housing, a water inlet along the side of the body, a lens, a piezoelectric material having a top and bottom surface, the top surface of the piezoelectric material being coupled to the lens, and two electrodes electrically coupled to the top and bottom surfaces of the piezoelectric material and configured for coupling to a power source.

[0006] The inlet and outlet are in liquid communication.

[0007] The support may be part of a dishwasher or clothes washer. For example, the support fork includes two rotating arms rotatably coupled to an inner underside of the machine, with a plurality of piezoelectric transducers on each arm.

[0008] Optionally, the support may include at least one slidable arm slidably coupled to an interior surface of the machine.

[0009] The support may be in the form of a helix or spiral.

[0010] When the machine is a clothes washing machine, it may include a non-rotatable drum with a support coupled to an interior surface of the drum. Optionally, the drum may be the support. The transducer includes a plurality of donut-shaped transducers coupled to a bottom interior surface of the drum, the transducers being spaced around a periphery of the bottom interior surface of the drum.

[0011] Preferably, the piezoelectric material is lead zirconate titanate. [Brief description of the drawings]

[0012] These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings.

[0013] [Figure 1] 1 is a top perspective view of a piezoelectric transducer having a feature of the present invention in which the transducer may have one or more water inlets. [Diagram 2] FIG. 2 is a cross-sectional view of a transducer system utilizing the transducer of FIG. 1. [Diagram 3] FIG. 1 is a plan view of a piezoelectric transducer with a cylindrically focusing lens. [Figure 4]FIG. 4 is a perspective view of the transducer shown in FIG. [Diagram 5] 2 is a perspective view of a dishwasher having a plurality of the piezoelectric transducers of FIG. 1 mounted thereon. [Figure 6] 2 is a software control flow chart for a dishwasher having features of the present invention. [Figure 7] 2 is a top perspective view of a washing machine having a plurality of the piezoelectric transducers of FIG. 1 mounted thereon; [Figure 8] FIG. 1 is a perspective view of a non-rotating drum of a clothes washing machine with multiple transducers disposed along the interior surface of the drum. [Figure 9] FIG. 9 is an additional perspective view of the drum of FIG. 8, with a plurality of donut-shaped transducers provided at the bottom of the drum. [Figure 10] FIG. 9 is an additional perspective view of the drum of FIG. 8, with a plurality of donut-shaped transducers provided at the bottom of the drum. [Figure 11] FIG. 1 is a perspective view of a non-rotating drum of a clothes washing machine with multiple transducers arranged along the interior surface of the drum in a helical configuration. [Figure 12] FIG. 12 is an additional perspective view of the drum of FIG. 11, with a plurality of donut-shaped transducers provided at the bottom of the drum. [Figure 13] FIG. 13 is a schematic diagram of the drum of FIG. 12. [Figure 14] FIG. 13 is a top perspective view of a spherically focused transducer with two water inlets and a bleeder to prevent air trapping. [Figure 15] FIG. 2 is a top perspective view of a donut-shaped transducer. [Figure 16] FIG. 1 is a top perspective view of a spherically focusing lens. [Figure 17] FIG. 13 is a plan view of an additional configuration of transducers at the bottom of the drum of any of FIGS. 9, 10, or 12, in which the transducers are cylindrically focused and arranged in a spiral configuration. [Figure 18]2 is a software control flow chart for a clothes washer having features of the present invention. [Figure 19] FIG. 1 is a cross-sectional side view of a transducer with a backing coupled to a piezoelectric material that is sandwiched between two electrodes and coupled to a lens material having a planar surface. [Figure 20] FIG. 20 is a cross-sectional side view of the transducer of FIG. 19, in which the surface of the lens material is curved. [Figure 21] FIG. 20 is a perspective view of the transducer of FIG. 19. [Figure 22] FIG. 21 is a perspective view of the transducer of FIG. 20, in which the curved surface is cylindrical. [Diagram 23] FIG. 21 is a perspective view of the transducer of FIG. 20, in which the curved surface is spherical. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] As used herein, the following terms and variations thereof have the meanings given below, unless a different meaning is clearly intended by the context in which such term is used.

[0015] As used herein, the terms "a," "an," and "the" and similar referents are intended to cover both the singular and the plural, unless the context indicates otherwise.

[0016] As used in this disclosure, the terms "comprise" and variations of terms such as "comprising" and "comprises" do not exclude other elements or steps.

[0017] The present invention utilizes an improved acoustic transducer system that may be utilized in dishwashers and clothes washing machines, among other applications.

[0018] 1-4, a piezoelectric transducer (100) of the present invention is shown.

[0019] FIG. 1 shows the body (102) of one version of a transducer (100). The body (102) is cylindrical with a cylindrical side surface (104), a closed bottom surface (106), and a conical or pyramidal top surface (108) having at least one inwardly sloping surface (110). The body (102) has a water inlet along the side surface (108) of the body (102) and a drainage outlet centered on the top surface (108) of the body (102). The water inlet and drainage outlet are in liquid communication to allow water to flow from the water inlet to the drainage outlet. Along the interior surface of the bottom surface (106) of the body (102) is a layer of piezoelectric material (112). On top of the piezoelectric material (112) (distal to the bottom surface of the body (102)) is a lens (114).

[0020] The piezoelectric material (112) has an upper surface (116) and a lower surface (118). The lower surface (118) of the piezoelectric material (112) is proximate to the bottom surface (106) of the body (102), and the upper surface (118) of the piezoelectric material (112) is distal to the bottom surface (106) of the body (102). As mentioned above, the lens (114) is coupled to the upper surface (116) of the piezoelectric material (112). The lens (114) can be ionized aluminum, stainless steel, or glass, among others. Ionized aluminum is chemically and mechanically stable and relatively inexpensive.

[0021] Two electrodes (120) may be coupled to the bottom surface (118) and top surface (116) of the piezoelectric material (112). The electrodes (120) are spaced apart along the bottom surface (118) and top surface (116) of the piezoelectric material (112) and are electrically connected to a power source (122). The electrodes (120) may be a vacuum deposited thin layer (3500 Å) of chrome or chrome / gold. The electrodes (120) may be connected to the power source (122) by soldered wires. The piezoelectric material (112) need not be directly coupled to the body (102) of the transducer (100), and an air-filled space may be between the bottom surface (118) of the piezoelectric material (112) and the bottom surface (106) of the body (102).

[0022] FIG. 2 is a cross-sectional view of the transducer (100) of FIG. 1 with a water inlet located along one of the sloping sides (110) of the top surface (108) of the body (102).

[0023] 19 is a cross-sectional side view of a transducer (200) with an optional backing (202) shown. The backing (202) can be air, brass, synthetic rubber, or an acoustically lossy material. The piezoelectric material (112) is sandwiched between two electrodes (120) and a lens (114) having a flat surface.

[0024] FIG. 16 shows a transducer (300) with a curved lens (114). The curvature can be spherical, cylindrical, or optionally no curvature is used. The curvature of various types of lenses (114) results in different shapes of acoustic streams. For example, a spherical curved lens (114) of the transducer (300) focuses the energy (acoustic stream) to a near point, while a cylindrical curved lens (114) focuses the acoustic stream in a line or slot shape. The line or slot shape can be very narrow or wide, resulting in a thin or thick acoustic spray pattern. The shape of the drain further helps to focus the acoustic stream.

[0025] FIG. 20 is a cross-sectional side view of the transducer (200) of FIG. 19, but with a curved surface of the lens material (114).

[0026] FIG. 21 is a perspective view of the transducer (200) of FIG.

[0027] FIG. 22 is a perspective view of the transducer (200) of FIG. 20, in which the curved surface of the lens (114) is cylindrical.

[0028] FIG. 23 is a perspective view of the transducer (200) of FIG. 20, in which the curved surface of the lens (114) is spherical.

[0029] When an electric field is applied to a piezoelectric material, it changes its mechanical dimensions. This phenomenon is called the inverse piezoelectric effect, which is first order. A piezoelectric transducer is a type of electroacoustic transducer that converts an oscillatory electrical signal into vibrations in a piezoelectric crystal that can act as a wave source that propagates throughout the system. The active element is the heart of the transducer, as it converts the electrical energy into acoustic energy. The active element is essentially a ferroelectric material, such as PZT ceramics or lithium niobate, that exhibits a dipole moment. Above a certain temperature, known as the Curie point, the dipole directions have a random orientation. The dipoles can be aligned by applying a strong electric field at a temperature near the Curie point, a process known as poling. When an electric field is applied across an already poled material, the aligned dipole moments tend to expand or contract in the same direction causing the dimensions of the material to change. This phenomenon is similar but different from electrostriction. The difference is that the deformation due to electrostriction is proportional to the square of the applied electric field, so it does not depend on the direction of the electric field. On the other hand, the piezoelectric deformation is directly proportional to the electric field and opposite in sign to the electric field. Moreover, electrostriction is a universal property of dielectrics and its effect is always extremely small. Moreover, piezoelectricity is a reversible effect. For example, permanently polarized materials such as quartz (SiO2) or barium titanate (BaTiO3) create an electric field when the material changes dimensions as a result of an applied mechanical force. This phenomenon is known as the direct piezoelectric effect.

[0030] The active element of most acoustic transducers used today is a piezoelectric ceramic, which can be cut in various ways to produce different wave modes. The device has a resonant frequency that depends on the thickness of the active element and the lens and their piezoelectric properties. The preferred active element of the transducer of the present invention is Lead Zirconate Titanate and is further known as PZT. PZT has many variants, such as PZT4 and PZT5. Other piezoelectric materials, such as zinc oxide, may be used, but PZT is currently preferred because it can operate efficiently from 100 kHz to 30 MHz. Other materials, such as metamaterials, which convert electrical energy into acoustic energy, may also be used.

[0031] The frequency at which the transducer operates is determined by the material the lens is made of, the piezoelectric material, and the depth / height of the housing. Typically, the transducer operates at high frequency (frequency range can range from a few Hertz to over Gigahertz) and generates high power acoustic waves that can have very narrow to very shallow focusing. Preferably, the transducer operates in the ultrasonic or megasonic range. The acoustic waves vibrate the water molecules.

[0032] 3 and 4 show a transducer (400) having a rectangular body (102).

[0033] In FIG. 3, the drain is a narrow rectangular strip along the top surface (108) of the body (102), rather than a circular hole as in the spherical body (102) of the transducer (100) of FIGS.

[0034] As mentioned above, the backing material (202) is optional, and therefore the transducers (100), (200), (300), (400) may not have a backing material (202). Instead, the air in the transducers (100), (200), (300), (400) may be considered the backing material.

[0035] In use, water enters the housing (102) of the transducer (100), (200), (300), (400) via the water inlet. Once the water contacts the curved surface of the lens (114), the sensor activates the transducer (100), (200), (300), (400), causing it to vibrate. The water exits the housing (102) of the transducer (100), (200), (300), (400) via the drain, using an acoustic stream that can be sprayed onto a dish or clothing.

[0036] Optionally, the transducers (100), (200), (300), (400) do not have a lens (114).

[0037] As shown in FIG. 14, the transducer (100) may optionally include a bleeder to prevent trapped air.

[0038] Acoustic streaming is introduced into a water jet (e.g., in a dishwasher) by mounting transducers (100), (200), (300), (400) inside each opening of the spray bar where the water stream exits the spray bar.

[0039] In one embodiment, the invention is a system (500) that includes a support (502) (e.g., a hollow rod or spray bar in a dishwasher (504)) having multiple transducers (100), (200), (300), (400) mounted thereon. The support (502) can be made in different shapes and configurations, from vertical to horizontal, spiral to elliptical to helical, and circular to cylindrical. See Figures 7-13 for exemplary support (502) shapes / configurations.

[0040] The substrate (502) (spray bar) can be positioned in any orientation within the dishwasher (504), and optionally the dishwasher (504) can include multiple substrates (502) to achieve a desired level of cleaning.

[0041] Referring to FIG. 5, a dishwasher (504) having features of the present invention is shown. The bottom of the dishwasher (504) has two rotating spray arms (supports) (502A) and the traditional water exit holes have been replaced with piezoelectric transducers (100), (200), (300), (400). Optionally, an upper spray bar (support) (502B) is mounted along the top of the dishwasher (504) and a side spray bar (support) (502C) is mounted along the side wall of the dishwasher (504). The transducers (100), (200), (300), (400) are positioned along the length of the upper and side spray bars (supports) (502). The side spray bar (502C) can be slidably connected to the side wall of the dishwasher (504) so ​​that it can slide back and forth along the side wall while remaining vertical. The upper spray bar (502B) may further be slidably connected to the top of the dishwasher (504) so ​​that it can slide / move side to side while remaining oriented horizontally.

[0042] Optionally, the dishwasher (504) may have only one upper spray bar (502B), only one side spray bar (502C), or only one rotating spray arm (502A) at the bottom of the dishwasher (504) with the transducers (100), (200), (300), (400) mounted thereto.

[0043] A possible transducer configuration is sixteen transducers (100), (200), (300), (400) adjacent to or at the bottom of the dishwasher (504) and an additional sixteen transducers (100), (200), (300), (400) positioned throughout the body of the dishwasher (504).

[0044] Typically, the spacing between the transducers (100), (200), (300), (400) may vary between 1 and 4 inches. A typical total number of transducers (100), (200), (300), (400) in a dishwasher (504) may vary between 20 and 40 transducers.

[0045] Each of the transducers (100), (200), (300), (400) has its own frequency. Optionally, all the transducers (100), (200), (300), (400) can operate in unison, or the transducers can operate at different frequencies and at different times to cover a wider frequency band. The transducers (100), (200), (300), (400) can operate continuously over the cleaning cycle, or the transducers can operate in bursts over the cleaning cycle.

[0046] The transducers (100), (200), (300), (400) discussed above may be utilized in dishwashers (504), clothes washers, and optionally clothes dryers (discussed in more detail below), among other devices.

[0047] Referring now to FIG. 6, there is shown a flow chart of the software control of a dishwasher (504) having features of the present invention.

[0048] As the water jets from the jet bar (support) (502) inside the dishwasher (504), acoustic energy is injected using multiple piezoelectric transducers (100), (200), (300), (400) that vibrate the water molecules at a given frequency. The impact of the acoustic water jet on the dirty dishes gives rise to three new cleaning mechanisms in addition to those due to the impact force. First, the back and forth action of the vibration of the water molecules creates a cleaning action similar to that caused by scrubbing with the hands. However, this action occurs without any mechanical contact with a solid such as a brush or sponge. Second, the vibration of the water molecules creates body waves in the dishes, which help to remove food particles from the surface. Third, the action of the acoustic jet creates surface waves, which tend to separate the dirty dishes from the stickier ones. The cleaning action is further due to cavitation and the formation of bubbles, which help to remove food stuck to the dishes.

[0049] When the dishes are clean and the drying cycle begins, multiple transducers (100), (200), (300), (400) can be used to create acoustic mini-tornadoes of air inside the dishwasher (504) to speed up the drying process.

[0050] As mentioned above, the support structure of the present invention can also be a structure in a clothes washer (700), and optionally, a clothes dryer. The clothes washer (700) has at least one support (702) attached thereto, and the typical tumbling action of clothes can be mimicked by moving the various supports (702), so that the surface of the clothes can be exposed to the acoustic streaming of the supports (702). The movement of the supports (702) eliminates the need for a rotating drum, which may reduce the manufacturing costs of the clothes washer (700). Furthermore, the present invention saves both time and energy, since the clothes are washed more efficiently than the random tumbling action to which they are typically exposed. Furthermore, since a rotating drum is not required, the drum does not need to be a cylindrical drum. It can be a different shape, such as a cone shape, which focuses the energy of the clothes washing more efficiently.

[0051] In a washing machine (700) constructed with either a stationary cylindrical drum or a conical drum, the support (702) can be constructed with different shapes and forms to create an acoustic mini-tornado of water and detergent that tumbles the clothes during the washing process.

[0052] In a clothes drying process, the transducers (100), (200), (300), (400) of the present invention are air transducers (rather than water transducers). The transducers (100), (200), (300), (400) create an acoustic air flow (rather than an acoustic water flow). Drying occurs by conveying an air flow over the clothes even when the clothes are not in mechanical contact with the transducer. Alternatively, the water transducer and the air transducer can be mounted side by side.

[0053] Air temperature and pressure can be adjusted and optimized to minimize overall energy consumption and suit the type of fabric.

[0054] Additionally, the cleaning or drying process can be enhanced by activating an acoustic shaker, such as a donut-shaped transducer (704) attached to the body of the unit holding the articles. See Figure 15 for a top perspective view of the donut-shaped transducer (704).

[0055] Referring to FIG. 8, a clothes washing machine drum (800) is shown having an open top (802) and a closed bottom (804). The drum (800) can be rotating or non-rotating. A number of piezoelectric transducers (100), (200), (300), (400) are utilized to provide efficient washing of the clothes. In FIG. 8, the drum (800) is non-rotating and has a number of transducers (100), (200), (300), (400) arranged along the interior surface of the drum (800) in a number of lines (supports) (806). The lines (806) can be of any shape, including vertical lines extending from bottom to top. The transducers (100), (200), (300), (400) can be rectangular, spherical, or preferably cylindrical. The number of lines (806) may range from 6 to 12 and the number of transducers (100), (200), (300), (400) per line may range from 2 to 4.

[0056] 9 and 10, the non-rotating drum (800) of FIG. 8 is shown, with the bottom (804) of the drum comprising donut-shaped flat transducers (704) which may range in number from 7 to 13.

[0057] Referring to Figure 11, there is shown a non-rotating drum (800) with transducers (100), (200), (300), (400) arranged along the interior surface of the drum (800) in a helix shaped line (support) (806). The number of transducers (100), (200), (300), (400) can range from 12 to 48, and preferably the transducers are cylindrically focused.

[0058] Figure 12 is the same configuration as in Figure 11, except that the bottom surface (804) of the drum (800) is provided with doughnut-shaped flat transducers (704) whose number may range from 7 to 13. Figure 13 is a schematic of Figure 12.

[0059] FIG. 14 shows one of the spherically focused transducers with two water inlets and a bleeder to prevent air trapping.

[0060] FIG. 15 shows one of the donut shaped transducers (704).

[0061] FIG. 16 shows one of the spherically focusing transducer lenses (114).

[0062] 17 shows another possible configuration of transducers (100), (200), (300), (400) on the bottom (804) of a drum (800). These transducers (100), (200), (300), (400) are smaller than the flat donut-shaped transducers (704) referenced above, and may be focused into a cylindrical or spherical shape and arranged in a line (806) in the form of a spiral.

[0063] FIG. 18 is a software control flow chart for a washing machine (700) having features of the present invention.

[0064] As indicated above, various support structure configurations are possible, such as helical or spiral, depending on the application.

Claims

1. 1. A system for generating and directing acoustic streaming, the system comprising: a) at least one support, and b) a plurality of piezoelectric transducers supported by the support, each of the piezoelectric transducers comprising: i) a cylindrical housing having cylindrical sides and a closed bottom, with a conical top surface, or a polygonal housing having sides and a closed bottom, with a polyhedral top surface, with a drain opening centrally along the top surface of the housing; ii) a water inlet along the side of the housing; iii) a spherical curved lens or a cylindrical curved lens; iv) a piezoelectric material having a top surface and a bottom surface, the top surface of the piezoelectric material being coupled to the lens; and v) a piezoelectric transducer including two electrodes electrically coupled to the bottom and top surfaces of the piezoelectric material and configured for coupling to a power source; the substrate is part of a dishwasher or clothes washer; The support includes at least one slidable arm slidably coupled to an interior surface of the machine.

2. 2. The system of claim 1, wherein the support includes two rotating arms rotatably coupled to an interior bottom surface of the machine, with a plurality of piezoelectric transducers mounted on each arm.

3. The system of claim 1 , wherein the support is helix-shaped.

4. The system of claim 1 , wherein the support is spiral shaped.

5. The system of claim 1 , wherein the clothes washing machine includes a non-rotatable drum, the drum being the support.

6. The system of claim 5 , wherein the piezoelectric transducer comprises a plurality of donut-shaped transducers coupled to an interior bottom surface of the drum.

7. The system of claim 6 , wherein the donut-shaped transducers are spaced around a periphery of the interior bottom surface of the drum.

8. The system of claim 1 , wherein the piezoelectric material is lead zirconate titanate.

9. 1. A system for generating and directing acoustic streaming, the system comprising: a) at least one support, and b) a plurality of piezoelectric transducers supported by the support, each of the piezoelectric transducers comprising: i) a body having a cylindrical or multi-polygonal side, a closed base, and a top surface, the drain opening being centrally located along the top surface of the body; ii) a water inlet along the side of the body; iii) a spherical curved lens or a cylindrical curved lens; iv) a piezoelectric material having a top surface and a bottom surface, the top surface of the piezoelectric material being coupled to the lens; and v) a piezoelectric transducer including two electrodes electrically coupled to the bottom surface and the top surface of the piezoelectric material and configured for coupling to a power source; the substrate is part of a dishwasher or clothes washer; The support includes at least one slidable arm slidably coupled to an interior surface of the machine.

10. 10. The system of claim 9, wherein the support includes two rotating arms rotatably coupled to an inner bottom surface of the machine, with a plurality of piezoelectric transducers mounted on each arm.

11. The system of claim 9 , wherein the support is helix-shaped.

12. The system of claim 9 , wherein the support is spiral shaped.

13. 13. The system of claim 12, wherein the support is coupled to an interior surface of a drum of a clothes washing machine that includes a non-rotatable drum.

14. The system of claim 13 further comprising a plurality of donut-shaped transducers coupled to an interior bottom surface of the drum.

15. The system of claim 14 , wherein the donut-shaped transducers are spaced around a perimeter of the interior bottom surface of the drum.

16. The system of claim 9 , wherein the piezoelectric material is lead zirconate titanate.

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