What Is an Ultrasonic Homogenizer?
An ultrasonic homogenizer is a device that homogenizes particles and liquids by irradiating a particle-containing liquid with ultrasonic waves.
Particles can be solids or droplets within a liquid. Ultrasound generates very small bubbles (ranging from several hundred to tens of micrometers) in the liquid. When these bubbles burst, they create turbulence in the solution.
This turbulence impacts the particles, crushing large ones and atomizing them, thereby dispersing particles to homogenize the solution. Ultrasonic homogenizers can prepare stable homogenized suspensions and emulsified liquids, even where ordinary mechanical stirring is ineffective.
Applications of Ultrasonic Homogenizers
Ultrasonic homogenizers are used in various applications, notably for producing stable homogenized liquids such as suspensions and emulsions.
1. Food and Dairy Production
In food and dairy processing, ultrasonic homogenizers create dispersions and emulsions, ensuring product stability and quality.
2. Manufacture of Cosmetics
In cosmetics manufacturing, their ability to achieve stable emulsification aids in producing high-quality creams, lotions, and similar products.
3. Other
Ultrasonic homogenizers also adjust the stability and viscosity of dispersions and suspensions in ceramics, pigments, minerals, etc. They are used in biology and microbiology, research and development for cell tissue and virus disruption, and DNA and protein extraction. Their use extends to materials research, particularly for suspension and emulsification processes.
Principle of Ultrasonic Homogenizer
1. Generation of Ultrasonic Waves
An ultrasonic homogenizer’s key components include an oscillator and a transducer. The oscillator emits an electrical signal, causing the transducer’s tip (or horn) to vibrate vertically at approximately 20,000 times per second.
These vibrations, when transmitted to the liquid, propagate as ultrasonic waves.
2. Cavitation
As sound waves are longitudinal, they create high and low-density areas in the liquid, forming vacuum bubbles in low-density zones. This phenomenon, known as cavitation, produces these bubbles.
3. Crushing, Dispersion, and Homogenization
When a bubble bursts, it generates powerful turbulence, breaking up agglomerated particles. This process, repeated through cavitation, refines particles in the liquid, enhancing homogenization.
Features of Ultrasonic Homogenizer
The key features and considerations of ultrasonic homogenizers are as follows:
1. Relatively Low Risk of Foreign Matter Contamination
Unlike conventional mechanical homogenizers with many contact surfaces, ultrasonic homogenizers have fewer contact points and do not physically interact with particles, thus reducing contamination risk.
2. Low Maintenance and Management Costs
As no physical force is applied for crushing, equipment wear due to friction is minimized, thereby reducing maintenance and management costs.
3. Suitable for Homogenizing Particle Size Distribution
In the final homogenization stages, particulation is primarily due to particle collisions, often resulting in spherical particles. This is ideal for achieving uniform particle size distribution.
4. Excessive Breakdown of Components May Occur
The high energy of ultrasound can be overly destructive, especially for biological samples where cell disintegration can occur. However, this property is sometimes desirable, such as in cell disruption processes.
5. Heat Generation
The heat generated during use can denature proteins in biological samples. Therefore, optimizing processing time and irradiation intervals with cooling is necessary.