EP0962261A1 - Device for treating fluids and/or solids - Google Patents

Abstract

The arrangement has at least one torsional oscillator (20), pref. with a longitudinal converter, and a torsional transducer for producing a torsional ultrasonic oscillation with a predefined oscillation frequency. A sonotrode (3) is connected to the torsional oscillator and can be set into torsional oscillation. The sonotrode is designed so that its resonant frequency corresp. approximately to the torsional oscillator frequency and with structures (4) for transferring the torsional oscillation to the fluid. An Independent claim is also included for the use of a resonantly vibrating torsion sonotrode for processing fluids and solids.

Description

The invention relates to a device for treating Fluids and / or solids according to the features of the generic term of claim 1.

It is known that ultrasound is a series of mechanical, triggers chemical and biological effects. The stake of ultrasonic disintegrators for dispersing, emulsifying, Homogenizing, degassing, accelerating chemical Reactions, crushing particles and cell walls is well known and is e.g. also in the following books described: (1) Ultrasound technology: basics and application / ISBN 3-87664-106-3, (2) Heinrich Kuttruf: Physics and Technology of ultrasound / ISBN 3-7776-0427-5, (3) Timothy J. Mason: Practical Sonochemistry / ISBN 0-13-682642-3.

The sonochemical reactions are generally based on the Effect of cavitation (2, p. 333). Become ultrasonic vibrations with a sufficiently large amplitude on a liquid transmitted, oscillating bubbles are created by the alternating compression and expansion phases. This The process is often referred to as cavitation. In the bubbles high temperatures and pressures arise for a short time. this will in chemical reactions of the bubble content such as in the homolytic splitting of water or in the degradation of Exploited pollutants. High speed currents arise with bubbles that are close to solid borders are located. This creates high shear forces which for crushing solid agglomerates or lead emulsified drops. Turbulent flows in the Cause the environment of the mostly non-linearly oscillating bubbles also high shear forces, for example in colloid mills to produce emulsions or to disperse particles be used. Occur very quickly when bladder collapse Bubble wall speeds up, so are shock waves emits which small particles accelerate and can cause comminution in the µm range.

Ultrasonic high-performance disintegrators are mainly used in industry or reactors used. Through a Compound transducers (1, p. 83) are tuned to resonance Sonotrodes (1, p. 372) stimulated to stretch vibrations. These sonotrodes both radiate the vibrations radial as well as longitudinal. The longitudinal vibration amplitude is usually about three times larger than that radial component. The radially radiated energy is mostly not to be used as useful energy and limits efficiency the sonotrode. The for the generation of sonochemical Effects of the longitudinal vibration amplitude as high as possible is always with corresponding radial losses paired.

Another disadvantage of the usual combination of transducers a composite transducer and a longitudinal sonotrode the maximum power limited by the compound transducer. Furthermore, the radial expansion of the sonotrode cannot can be expanded as desired, otherwise the proportion is parasitic radial vibrations increases. The one available The effective area for transmitting the vibrations is therefore limited. These restrictions limit the use of longitudinally vibrating sonotrodes in technical Application tremendous.

Tools are from the field of ultrasonic metal welding known with torsional excitation or torsion sonotrodes. Such a torsion sonotrode is, for example, in the book von (4) Wilhelm Lehfeld: Ultrasound / ISBN 3-8023-0060-2, p. 91 mentioned.

JP-8-281227 A (WPINDEX; No. 97-015590) is a cleaning device known in which gear-like structure to be reciprocated. The wings of the Gears transmit motion to a treatment liquid creating a cavitation phenomenon. With This device is a tornado-like and in the container therefore creates cavitation that is difficult to control.

Tangential vibrations are generated with torsion sonotrodes, which are not emitted into a medium surrounding them can. Fluids such as gases and liquids can cause torsional vibrations next to no forwarding. Longitudinal only Vibrations are caused by changes in density in such media forwarded. Torsional vibrators conduct their energy when Continue welding only on materials, the corresponding tangential forces can pass on, such as metals or other solids. Therefore, they are not used for treatment of fluid substances or mixtures of substances.

The prior art devices for Treatment of liquids, liquid mixtures or Liquid-solid mixtures with longitudinal vibration systems, consisting of a composite transducer and a sonotrode, can only because of the limitations up to a total performance of approximately 2 kW per sonotrode. Radial radiation losses are accepted, to enable the highest possible amplitudes in the axial direction. Due to the design of the longitudinal sonotrodes are the sound-emitting surfaces are usually small, so that the The amount of fluid to be treated is limited. Furthermore these longitudinal oscillators can only be realizing narrow geometric boundaries. Because in the area of High-intensity ultrasound in technical applications large throughputs of fluid are required, a high one Total power input at high amplitude through a new type Form of ultrasound introduction into a fluid medium be made possible.

It is an object of the present invention to address the disadvantages to avoid the known, in particular a device to treat liquids that create the best possible efficiency is the transfer of high power allowed in the medium to be treated. The device should be simple to manufacture and maintain and should also the generation of precisely controllable amplitudes allow for vibration input into the liquid.

According to the invention, these tasks are carried out with one device with the features of the characterizing part of claim 1 solved.

In this context, torsional vibrations have emerged as suitable means for generating high amplitudes highlighted at the same time low losses.

A combination of torsional vibrations with optimized Efficiency and high performance with an application in Fluids such as liquids and gases and distributed therein Solids are suitable in the application according to the invention the sonochemical processes that are currently technically feasible sustainably improve and industrial use feed. A high ultrasound density is defined as an input per unit volume, and one if possible high throughput of fluid to be treated in the foreground.

The device according to the invention for treating fluids or solids consists essentially of at least one Torsional vibrator for generating a torsional ultrasonic vibration (Frequency 15-100 kHz) with a predetermined one Vibration frequency and from a sonotrode, which with the Torsional vibrator is connected, and what with this in torsional vibrations is displaceable. Under torsion vibrator is understood here a vibrator that is able the longitudinal vibrations of an ultrasonic converter (often referred to as a composite vibrator) in torsional vibrations convert. The torsional vibrator is advantageous from a converter and a torsion converter connected to it. The torsion converter has one or more component parallel to the axis of the converter and a perpendicular, approximately cylindrical component on. The dimension and shape of the two components will be like this chosen that the natural frequency of the torsional vibrator Corresponds to the excitation frequency of the converter. The sonotrode is with structures for transmitting the torsional vibration provided in the fluid. According to the features of the invention the sonotrode is designed in such a way that its natural frequency Vibration frequency of the torsional vibrator essentially corresponds. Thanks to this targeted training of the sonotrode the whole device resonates as a whole.

When examining smooth torsional vibrators in liquids could only find minor sonochemical effects because the radiation emitted by the sonotrode tangential vibrations not in the surrounding fluid Medium can be transferred.

Only by attaching structures such as ridges, Holes, notches, which are of longitudinal tangential amplitude Add component is the energy of the torsional vibrator radiated into a fluid medium. this has the advantage that almost exclusively in places where the above structures on the side of the torsion transducer were attached, energy into the work to be done Medium is passed on. All other types of radiation are avoided, which is extremely good efficiency results.

The sonotrode is advantageously essentially axially symmetrical trained and the length of the sonotrode is Half the wavelength of the vibration of the torsional vibrator or a multiple thereof. With such a construction the sonotrode will resonate with the torsional vibrator brought.

The structures for transmitting the torsional vibration in the medium surrounding the sonotrode advantageously have the circumference of the sonotrode arranged surfaces, which at least partially radial with respect to the axis of the sonotrode Have surface components. With radial surface components it is understood here that the structures Have surfaces that are not tangent to the sonotrode stand, but at an angle to the surface Form the sonotrode.

The structures along a circumferential line are advantageous arranged on the sonotrode, along which the sonotrode vibrates at maximum amplitude. The energy in the sonotrode can thus be located particularly effectively and precisely in the fluid to be treated can be entered.

The structures advantageously consist of one over the other Tooth-like structure extending around the sonotrode, which is provided with cavitation wings that are radial extend outwards. The surfaces of the cavitation wings do not extend directly from the axis of the sonotrode, but only from the roughly cylindrical surface of the Sonotrode radially outwards.

The ultrasonic vibration is therefore only in one area adjacent to the structures transferred into the fluid while along the smooth surface of the sonotrode, which is not is provided with structures, little or no vibration transmission he follows.

The structures are also advantageously interchangeable educated. Because the cavitation is almost exclusively due to this structure is also generated by cavitation generated material fretting in the area of these structures extraordinary big. Due to the interchangeable training of Structures can be easily replaced without one complete replacement of the sonotrode is required.

In addition, the sonotrode itself can also be detached with the Connected to the transducer. This also simplifies Replace the sonotrode if it is damaged.

There are torsion transducers, which, as described above, one maximum amplitude and therefore maximum power within of physical possibilities to produce torsional vibrations used. By using it one or more converters on the torsion converter (s) overall performance can be increased significantly. In the the technology currently possible powers of 2 kW at longitudinal vibrating sonotrodes can be multiplied in this way.

One or more converters transmit the vibrations to the Sonotrode and generate the transverse vibrations. On selected locations or distributed over the entire transverse page Structures are attached to the torsional vibrations as longitudinal waves in the surrounding fluid Medium transferred. This makes it much better achieve sonochemical effects than with the usual longitudinal Sonotrodes.

In the axial direction there are lengths of several half wavelengths (λ / 2) possible without loss of performance. Through the radiation the sound energy from the structures on the side surfaces or amplitudes can be generated on the end face, which lie above the longitudinal sonotrodes.

According to the invention, it has proven to be advantageous Working frequencies between 15 and 100 kHz (ultrasound) to use. It is possible to swing the System frequency and amplitude modulated, or just to operate frequency-modulated or only amplitude-modulated.

The device also preferably has a container for receiving the fluid, with the sonotrode inside of the container is arranged. It is between one Inner wall of the container and the surface of the structures Gap formed, the width of which is preferably chosen in this way will that between the structures and the inner wall of the Container in the fluid shear forces are caused.

The media to be treated can flow through the container are operated or operated in batches. Because of the hermetic Sealing the container can be an operation under pressure to be possible. Sealing the converter also allows the Use in potentially explosive environments.

The seal or connection between the torsion transducer and Vessel is advantageously carried out in a vibration node (no deflection of the torsional vibrator at the zero point of the amplitude).

A circumferential line of the torsion vibrator is here under vibration node understood which does not vibrate, i.e. which has an oscillation amplitude of approximately 0. In order to the torsion transducer can be tight and tight in a cover of the vessel can be held without the holder Swinging movement impaired. The attachment can, for example by shrinking a flange onto the Torsion converter take place.

Inlets and outlets to the vessel enable a continuous Flow of the media to be treated. By the distance between the torsion sonotrode and the vessel wall in a particularly advantageous manner the energy density and thus adjust the treatment intensity. In addition, at the Cavitation structures are also attached to the inside of the vessel which reinforce the sonochemical effects and serve for flow guidance.

The sonotrode also advantageously has a change in cross section on. With such a change in cross-section it is possible to change the amplitude of the vibration.

The inventive construction of the device with a Sonotrode, which resonates with a torsion transducer, which excites the sonotrode to a torsional vibration to various advantages.

In particular, the efficiency of the device can be massive can be increased, making higher with predetermined generators Services are transferred into the medium to be cleaned can. Thanks to the vibrations the sonotrode is in resonance it is also possible to have precisely controlled amplitudes of the Generate vibration or the amplitude and energy of the control and regulate transmitted vibrations. The The device can, for example, have a constant amplitude (by changing the power of the ultrasonic generator) or with constant performance depending on different Media or presses are operated. The exactly determinable maximum amplitude also allows the controlled Operation of the device below maximum amplitudes, which could damage the device.

Fig. 1a

Seitenansicht einer erfindungsgemässen Vorrichtung,

Fig. 1b

Draufsicht auf die Vorrichtung aus Fig. 1a,

Fig. 2a bis 2d

verschiedene Ausführungsformen von Sonotroden und Kavitationsstrukturen,

Fig. 3

schematische Darstellung des Amplitudenverlaufes benachbart zu den Kavitationsstrukturen,

Fig. 4

schematische Darstellung der in einem Behälter eingesetzten Vorrichtung mit schematischer Darstellung des torsionalen Amplitudenverlaufs,

Fig. 5a

Seitenansicht einer Anordnung mit mehreren Sonotroden und Torsionswandler, und

Fig. 5b

Draufsicht auf die Anordnung aus Fig. 5a.

The invention is explained below in exemplary embodiments and with reference to the drawings. Show it:

Fig. 1a

Side view of a device according to the invention,

Fig. 1b

Top view of the device from Fig. 1a,

2a to 2d

different embodiments of sonotrodes and cavitation structures,

Fig. 3

schematic representation of the amplitude curve adjacent to the cavitation structures,

Fig. 4

schematic representation of the device used in a container with a schematic representation of the torsional amplitude profile,

Fig. 5a

Side view of an arrangement with several sonotrodes and torsion transducers, and

Fig. 5b

Top view of the arrangement from Fig. 5a.

1a shows a device 10 for treating fluids and solids. A converter 1, which in longitudinal Direction swings, transmits the longitudinal vibrations to a torsion converter 2. The converter 1 and the torsion converter 2 form a torsional vibrator 20. The torsional vibrator 20, in particular the torsion converter 2 transmits the transverse vibrations on a torsion sonotrode 3. The torsion sonotrode 3 is essentially cylindrical formed and has a diameter of is larger than the diameter of a substantially cylindrical trained torsional vibrating component of the Torsion converter 2. Due to this increase in diameter the amplitude of the transverse vibration of the torsion sonotrode 3 increased. The torsional vibrator 20 is geometric constructed such that it resonates with the excitation frequency of converter 1 stands.

The amplitude of the converter 1 can also be be enlarged by changing the cross-section accordingly. It is essential to the invention that the torsion sonotrode 3 is designed such that its natural frequency Vibration frequency of the torsional vibrator 20 corresponds. The Connection between the longitudinal component and the Torsional component of the torsion converter 2 takes place a place where the longitudinal component with maximum Amplitude swings.

Cavitation structures 4 are located on the torsion sonotrode 3 attached which the sound energy into the surrounding fluid Forward medium. The cavitation structures 4 are along a circumferential line 20 of the torsion sonotrode 3 is attached, which vibrates with maximum amplitude.

The length of the torsion sonotrode 3 corresponds to half the Wavelength λ with which the torsional vibrator 20 vibrates.

The device 10, consisting of the torsion converter 2 and the sonotrode 3 is closed as a closed structure consider which with a predetermined excitation frequency of converter 1 is self-resonating. Because of This construction can make the energy particularly effective be exploited.

1b is a top view of the device 20 according to FIG Fig. 1a shown. Arrows indicate the longitudinal movement of the Torsion converter 2 and the torsional movement of the torsion converter 2 on. The torsion converter 2 and thus also the torsion sonotrode 3 swing around axis A. Cavitation structures 4 are attached along the circumference of the sonotrode 3. The cavitation structures 4 have surfaces 12 which from the surface of the sonotrode 3 radially from the axis A extend outwards.

2a to 2d show cavitation structures corresponding to the invention 4 on a torsion sonotrode 3.

Cavitation blades 5 and 5 have proven to be particularly advantageous Slots 6 on the front and long sides of the torsion sonotrode 3 proven. The cavitation structures are like this designed that they have a longitudinal sound radiation allow into the fluid medium.

It is conceivable to attach several cavitation structures which are spaced apart by about half the wavelength are arranged (see Fig. 2a and 2d). Furthermore it is conceivable to increase the cross section of the sonotrode 3 17 to be provided.

The configuration of the cavitation structures 5, 6 is according to 2a to 2d particularly advantageous. The invention is but also feasible with other structures. That's the way it is conceivable, not exactly radial surfaces, but slightly sloping surfaces, lamellas or continuously interlocking insert transitional, rounded projections.

In Fig. 3 it is shown that the cavitation structures on Locations are arranged in which the sonotrode 3 with maximum Amplitude oscillates. Along the circumferential line 13 is the Maximum amplitude as shown in Fig. 3. The perimeter 13 is arranged at a distance from the upper edge of the sonotrode 3, which of the wavelength or a multiple thereof corresponds. The amplitude of the structures is advantageous about 100µm.

At these locations of maximum amplitude, the effect is sonochemical Effects when using cavitation wings, for example 5 highest.

The cavitation structures 5 can be detached with the torsion sonotrode 3 be connected. The torsion sonotrode can also be used as an option 3 be detachably connected to the corrosion converter 2.

4 shows the installation of a converter according to the invention 1, a torsion converter 2 and a torsion sonotrode 3 with Cavitation wings 5 shown in a container 7. The torsion converter 2 is connected to a flange 8. The connection and sealing takes place in a vibration node of the Torsion converter 2 along a circumferential line 14 with minimal Amplitude. Two feed and discharge lines 9 for the treating media are provided.

The container 7 has an inner wall 15. A gap 16 will between the surface of the cavitation structures 5 and the Inner wall 15 formed. If the width d of the gap 16 is chosen sufficiently small, shear forces in the Liquid between the cavitation structures 5 and Inner wall 15 generated.

The supply and discharge lines 9 allow a special effective treatment of a liquid. The liquid will in the gap 16 between the inner wall 15 and the surface guided past the cavitation structures 5. In this gap the entire concentrates from the torsion sonotrode 3 in the energy given off by the liquid. If the device in So the liquid runs mandatory through the gap 16 and is thus particularly effective treated.

5a and 5b show variants of the vibration system according to the invention with four converters 1a, 1b, 1c, 1d, one (Fig. 5b) or two (Fig. 5a) torsion transducers 2 and one or two torsion sonotrodes 3. This arrangement is used to increase of the total power used in the system.

The individual converters work in push-pull. If one Converter moves against the axis A of the torsion converter 2, the other converter 1b moves from the axis A. path.

Claims (14)

Device (10) for treating fluids and solids, with at least one torsional oscillator (20), preferably with a longitudinal converter (1) and a torsional transducer (2) for generating a torsional ultrasonic oscillation with a predetermined oscillation frequency, and with a sonotrode (3) which is connected to the torsion oscillator (20) and can be set into torsional vibrations,
characterized in that the sonotrode (3) is designed such that its natural frequency corresponds to the oscillation frequency approximately of the torsional vibrator (20), and that the sonotrode (3) with structures (4, 5, 6) for transmitting the torsional vibration into the fluid is provided. Device according to claim 1, characterized in that the sonotrode (3) is essentially axially symmetrical is formed, and that the length (L) of the sonotrode (3) half the wavelength (λ) of the vibration of the Torsional vibrator (20) or a multiple thereof. Device according to one of claims 1 or 2, characterized characterized in that the structures (4, 5, 6) over the Have surfaces (12) arranged around the circumference of the sonotrode (3), with respect to the axis (A) of the sonotrode (3) have a radial surface component. Device according to claim 3, characterized in that the structures (4, 5, 6) are adjacent to one with maximum amplitude vibrating circumferential line (13) the sonotrode (3) are attached. Device according to one of claims 3 or 4, characterized characterized in that the structures (4, 5, 6) by themselves Cavitation wings extending over the circumference of the sonotrode (3) (5) exist. Device according to one of claims 1 to 5, characterized characterized in that the structures (4, 5, 6) are interchangeable are trained. Device according to one of claims 1 to 6, with a Container (7) for receiving the fluid, the sonotrode (3) is arranged inside the container (7). Device according to claim 7, characterized in that the torsion converter (2) at least partially along one corresponding to a torsional zero point Circumferential line (14), preferably tightly with the container (7) is connected. Device according to one of claims 7 or 8, characterized characterized in that the container (7) inflow and / or Drain lines (9). Device according to one of claims 7 to 9, characterized characterized in that between the inner wall (15) of the Container and the surface of the structures (4, 5, 6) a gap (16) is formed, the width (d) of which is preferred is chosen such that between the structures (4, 5, 6) and the inner wall (15) of the container (7) in Fluid shear forces are generated. Device according to one of claims 1 to 10, characterized characterized in that several converters (1a, 1b, 1c, 1d), preferably two or four converters are provided, which are connected to one or two torsion transducers (2) are. Device according to one of claims 1 to 10, characterized characterized in that the sonotrode (3) preferably one has continuous cross-sectional change (17), which leads to a change in amplitude. Device according to one of claims 1 to 12, characterized characterized in that the transducer (1) frequency and / or amplitude-modulated is adjustable. Use of a resonating torsion sonotrode (3) for treating fluids and solids.

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