Detailed Introduction
Power ultrasound's most prominent and widely recognized effect in liquids is the dispersion effect. The dispersion action of ultrasound in liquids primarily relies on the cavitation effect of the liquid.
Ultrasonic dispersion can be employed without the need for emulsifiers, and in many cases, ultrasonic emulsification can achieve particle sizes below 1μm. The formation of this emulsion is primarily due to the strong cavitation effect of ultrasonic near the dispersion tool. The emulsifier can disperse paraffin in water, with the diameter of the dispersed particles reaching below 1μm.
Ultrasonic dispersion points typically feature low vibration and high acceleration. Ultrasonic dispersing devices have been widely applied in fields such as food, fuel, new materials, chemicals, and coatings.
Principle of Dispersion 1. Ultrasonic Generator: It boasts an efficiency of up to 90% and is compact with a light weight; (also known as ultrasonic drive power supply).
Ultrasonic Dispersion Equipment
2. Ultrasonic driving system, with a resonance frequency around 15kHz for high power output; the ultrasonic generator and resonance system form an automatic frequency tracking system; (comprising an ultrasonic vibratory transducer made of ultrasonic transducers and ultrasonic amplitude horns).
3. Ultrasonic Dispersion Tool (comprises an ultrasonic tool head connected to a vibrator).
4. Dispersal Containers. The working principle of the homogenizer involves the ultrasonic generator outputting high-frequency electrical pressure to an ultrasonic transducer. After the transducer converts the electrical energy into mechanical vibration and amplifies it, the dispersion tool then facilitates a strong dispersion and micronization process within the container.
3 Factors Influencing Effectiveness Two factors determine the effectiveness of dispersal: ultrasonic impact force; ultrasonic radiation time.
The flow rate of the treatment liquid is Q, the gap is c, the area of the flat plate in the relative direction is S, and the average time t required for a specific particle to pass through this space in the treatment liquid is: t = c * S / Q. To enhance the ultrasonic dispersion effect, it is necessary to control three elements: the average pressure p of the treatment liquid, the gap c, and the ultrasonic radiation time t(s).
Ultrasonic dispersion principle
Ultrasonic dispersion is widely used in various fields, such as food, cosmetics, and chemicals. The application of ultrasonic dispersion in the food industry can be generally categorized into three types: liquid-liquid dispersion (emulsions), solid-liquid dispersion (suspensions), and gas-liquid dispersion. [3]
Solid-liquid system dispersion (suspension): such as the dispersion of powder emulsion.
Gas-liquid system dispersion: For the production of carbonated beverage water, the CO2 absorption method can be employed to enhance stability.
Liquid-liquid dispersion (emulsions): such as emulsifying ghee to produce high-grade lactose; dispersing raw materials during sauce production, etc.
Ultrasonic dispersion is also used in the preparation of nanomaterials; it is applied in food sample detection and analysis, such as the extraction and enrichment of trace amounts of bisphenol A in milk samples using ultrasonic-assisted liquid phase microextraction techniques.
