Ultrasonic Disintegration: Wetting, Dissolving, Dispersing
Ultrasonic Disintegrators and Their Applications
Ultrasonic disintegrators deliver intense shear forces, which creates the required impact on solids such as particles, crystals, and fibers to disrupt them and break them down to a targeted size, e.g. micron- or nano-size. When compared to alternative disintegration methods such as high-shear blade mixers, high-pressure homogenizers, bead mills, microfluidizers etc. ultrasonic disintegrators offer some major advantages.
Advantages of Ultrasonic Disintegrators
- High-intensity cavitation and shear
- Uniform particle processing
- High solid concentrations
- No nozzles / no clogging
- No milling medium (i.e. beads) required
- Linear scalability
- Easy & safe operation
- Easy to clean
- Time- & energy-efficient
The working principle of ultrasonic probe-type disintegrators is based on the generation of acoustic cavitation. Through the ultrasonic probe, high- intensity ultrasound waves are transmitted into the process medium (i.e. liquid or slurry). The ultrasound waves travel through the liquid, there where they create alternating high-pressure, low-pressure cycles. During the low pressure cycles minute vacuum bubbles, so called cavitation bubbles, occur. These cavitation bubbles grow over several pressure cycles until they reach a size, where they cannot absorption any more energy. At this point, the cavitation bubbles implode violently and create locally extreme conditions such as very high temperatures, pressures, extreme temperature and pressure differentials (due to high heating / cooling rates and pressure fluctuations), micro turbulences and liquid streams with velocities of up to 180m/s. Those conditions exhibit significant mechanical effects on particles in the medium, since the high-velocity liquid streams accelerate the particles in the medium so that particles collide. By inter-particle collision, solid matter (e.g., particles, fibres, cells) erode, shatter and are fragmented into micron- and nano-sized bits.
The high turbulences created by ultrasonication increase the mass transfer between phases and promote thereby the dissolving of powders or heterogeneous chemical reactions. This makes ultrasonic disintegrators the preferred tool to intensify processes such as milling, dispersing, emulsification, and dissolving.
Applications of Ultrasonic Disintegrators
- Milling & Grinding
- Deagglomeration & Dispersion
- Dissolving of powders
- Improving mass transfer
- Sonochemical reactions
Ultrasonic Disintegrators for Particle Size Reduction
Ultrasonic disintegrators are used for particles size reduction and particle distribution, wether this means real comminution of primary particles (referred to as milling) or the breakage of agglomerates (referred to as deagglomeration / dispersion).
Ultrasonic Disintegrators for Milling & Grinding
Ultrasonically generated cavitation creates intense shear forces and thereby related inter-particular collision. The solids in the slurry act as milling medium (comparable to beads or pearls in a bead / pearl mill): They get accelerated by the cavitational liquid streams, which easily achieve velocities of up to 180m/s. When the particles hit each other with such enormous speed, they break and shatter into micron- and nano-sized fragments. Ultrasonic disintegrators can even break primary particles. Ultrasonic flow cell reactors ensure the uniform treatment of all particles so that ultrasonic milling results in a narrow particle size distribution.
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Ultrasonic Disintegrators for Deagglomeration & Dispersion
Ultrasonic process parameters can be very precisely controlled, so that ultrasonic disintegrators can mill primary particles when high amplitudes and elevated pressure are applied. On the other hand, ultrasonic disintegration systems can be also operated at lower amplitudes and milder conditions, so that the particle structure and surface remains intact, but agglomerates are broken apart and the individual particles are distributed uniformly in the slurry.
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Ultrasonic Disintegrators for Emulsification
When two immiscible liquids (e.g., water and oil) are sonicated, the ultrasonic cavitation disrupts the droplets – producing very small droplets of the two immiscible phases, which are then mixed together. As ultrasonic disintegrators easily produce nano-sized droplets, stabilised ultrasonic emulsions exhibit a long-term stability and a clear transparent appearance.
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Ultrasonic Disintegrators for Dissolving
Ultrasonic disintegrators are used to dissolve powder and tablets in a rapid, facile and safe procedure. Ultrasonically generated cavitation erode the surface of solids and transports the eroded fragments into the liquid producing thereby a homogeneous solution.
In the pharmaceutical industry, dissolving tablets is a daily task, e.g. for analytical purposes. When tablets are exposed to an aqueous environment, the tablet dissolves slowly in a very time-consuming process. Even with the usage of a common stirrer or blade agitator, the full dissolution of tablets remains time-consuming. Ultrasonic cavitation and its extraordinarily intense shear forces detach the particles from the tablet and transport them into the diluent, thereby keeping the mass transfer between tablet surface and fresh, unsaturated diluent continuously in progress. This makes ultrasonic dissolving a extremely rapid and efficient process, which helps to accelerate drug dissolution.
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How Does a Mechanical Disintegrator Work?
Ultrasonic lab disintegrators use the same mechanical principle as industrial disintegrators do. Disintegrator mixing systems disintegrate agglomerates and aggregates, solubilize solid matter or disperse solid particles in liquid mixes. Ultrasonic disintegration incorporates a high-intensity ultrasonic probe in a batch tank or in an in-line flow cell reactor. The probe (sonotrode) of the ultrasonic disintegrator vibrates in the liquid at a very high frequency and creates intense ultrasonic cavitation in the liquid. Each cavitation bubble collapse results in powerful shear forces, that break agglomerates, aggregates, and even primary particles. Also, ultrasonic cavitation produces high-speed cavitational streaming with up to 1000km/h. The cavitational liquid jets impinge particle agglomerates, rupture cell walls, improve material transfer within the slurry and disperse solids throughout the liquid volume. In the ultrasonic cavitation field, pressures alternate quickly and repeatedly between vacuum and up to 1000bar. A rotary mixer with 4 mixer blades would need to operate at a staggering 300,000 RPM to achieve the same frequency of alternating pressure cycles. Conventional rotary mixers and rotor-stator mixers create no significant amount of cavitation because of their limitation in speed.
Lab Ultrasonic Disintegrators
Probe-type ultrasonic devices are a very useful tool in every lab. An ultrasonic probe (also known as sonotrode) is a simple geometry and easy-to-clean titanium rod that couples ultrasonic vibrations into a liquid. Hielscher makes ultrasonic probes and tips in a wide range of sizes. For the most common disintegration of solids in the lab, ultrasonic probes of 3, 7, 14, or 22mm tip diameter are very useful. Other probe sizes and custom-size ultrasonic probes are available. Typical ultrasonic devices for laboratory disintegration range from 100 to 400 watts ultrasonic power.
Industrial Ultrasonic Disintegrators
Hielscher industrial disintegrators are high-power ultrasonic processors designed for heavy-duty continuous disintegration of large slurry streams. These industrial systems can easily handle high solid concentrations. Industrial ultrasonic probes are equipped with a flange that can be mounted to steel tanks, glass reactors or plastic containers in any orientation. Pressurizing the sonication vessel or flow cell intensifies the acoustic cavitation and thereby the sonication process. Typical ultrasonic industrial disintegration equipment ranges from 1000 to 16,000 watts of ultrasonic power per sonotrode.
Industries, where ultrasonic disintegration is widely found:
- Dispersing, dissolving, mixing of solid/liquid formulations
- Material science
- Sample prep before analysis
- Nano-particle applications
- Particle functionalization
- Phase transfer reactions
- Crystallization / Precipitation
- Food processing
- Paper industry
- Biomass digestion
How to Buy the Right Ultrasonic Disintegrator?
Hielscher Ultrasonics is long-time experienced manufacturer of high-performance ultrasonic disintegrators, which are used to disperse and break particles or to dissolve powders in liquids. As market leader, Hielscher designs, manufactures and distributes ultrasonic disintegrators and homogenizers from lab and bench top up to full-industrial scale.
We help you to answer the following questions in order to find the most suitable ultrasonic disintegrator for your application and needs:
- What is your target application?
- What is the typical volume that must be processed?
- What are the critical factors of the process?
- What are the quality standards, which must be achieved?
Our well trained and experienced staff will assist you with any questions and the conception of your process. Hielscher Ultrasonics offers an in-depth consulting on ultrasonic processes to help our customers finding the optimal ultrasonic device. But Hielscher’s service does not end here, we train customers either at their facilities or in our ultrasonic process lab and technical center to assist them during process development, optimization and scale-up.
Hielscher Ultrasonics’ industrial ultrasonic processors easily deliver very high amplitudes, which are required to break hard particles and agglomerates or to process slurries with a high solid concentration. Hielscher industrial disintegrators can be run with amplitudes of up to 200µm continuously in 24/7 operation. For even higher amplitudes, customized ultrasonic sonotrodes are available. Further accessories such as booster horns, flow cells, sonication reactors and complete recirculation setups are readily available and allow to configure your ultrasonic system specified to your process requirements.
Sophisticated Ultrasonic Disintegrators
Hielscher Ultrasonics focusses on high-performance disintegrators with highest user friendliness and state-of-the-art technical advances. This means that the standards of Hielscher lab disintegrators adapt more and more to the intelligence of industrial machinery. The user can control Hielscher’s digital ultrasonicators via browser remote control. The automatic data recording software writes all important ultrasonic parameters such as net power, total power, amplitude, temperature, pressure, time and date as CSV file on a built-in SD-card. Furthermore, the ultrasonic disintegrator can be programmed to automatic shut-off after a determined time or a specific energy input or program pulsating sonication modes. Pluggable temperature and pressure sensors allow for tracking the sample conditions carefully. Since temperature-control of heat-sensitive materials is a crucial factor for the quality of the process results, Hielscher offers various solutions to keep the process temperature in the targeted temperature range.
The sophisticated functions of Hielscher ultrasonicators assure the highest process control, reliable and reproducible sonication results, user-friendliness and working comfort.
Hielscher Ultrasonics’ industrial ultrasonic processors can deliver very high amplitudes. Amplitudes of up to 200µm can be easily continuously run in 24/7 operation. For even higher amplitudes, customized ultrasonic sonotrodes are available. The capability to run such high amplitudes enables our customers to mill primary particles efficaciously to nano-size. The robustness of Hielscher’s ultrasonic equipment allows for 24/7 operation at heavy duty and in demanding environments.
Quality – Made in Germany
As a family-owned and family-run business, Hielscher takes pride in the high quality of its ultrasonic processors. All ultrasonicators are designed, manufactured and tested in our headquarter in Teltow near Berlin, Germany. The robustness of Hielscher’s ultrasonic equipment allows for 24/7 operation at heavy duty and in demanding environments.
You can buy Hielscher ultrasonic disintegrators in all different sizes and the price range offers an affordable ultrasonicator matching your budget. From particle disintegration in small lab vials to the continuous flow disintegration of slurries in industrial production, Hielscher Ultrasonics has a suitable disintegrator for you! Please contact us – we are glad to recommend you the most suitable ultrasonicator!
The table below gives you an indication of the approximate processing capacity of our ultrasonicators:
|Batch Volume||Flow Rate||Recommended Devices|
|1 to 500mL||10 to 200mL/min||UP100H|
|10 to 2000mL||20 to 400mL/min||UP200Ht, UP400St|
|0.1 to 20L||0.2 to 4L/min||UIP2000hdT|
|10 to 100L||2 to 10L/min||UIP4000hdT|
|n.a.||10 to 100L/min||UIP16000|
|n.a.||larger||cluster of UIP16000|
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Literature / References
- Pohl M.; Schubert H. (2004): Dispersion and deagglomeration of nanoparticles in aqueous solutions. International Congress for Particle Technology PARTEC 2004; Nuremberg, Germany.
- Thomas Leong, Muthupandian Ashokkumar, Sandra Kentish(2011): The Fundamentals of Power Ultrasound. – A Review. Acoustics Australia, 54 – Vol. 39 August 2011.
- Karl A. Kusters, Sotiris E. Pratsinis, Steven G. Thoma, Douglas M. Smith (1994): Energy-size reduction laws for ultrasonic fragmentation. Powder Technology, Volume 80, Issue 3, September 1994. 253-263.
- Renata Tomczak-Wandzel, Svetlana Ofverstrom, Regimantas Dauknys, Krystyna Mędrzycka (2011): Effect of Disintegration Pretreatment of Sewage Sludge for Enhanced Anaerobic Digestion. ENVIRONMENTAL ENGINEERING The 8th International Conference May 19–20, 2011, Vilnius, Lithuania.