High-power ultrasonic sonochemical equipment
The most prominent and widely known effect of power ultrasound in liquids is the dispersion effect. The dispersion of ultrasonic waves in liquids mainly depends on the ultrasonic cavitation of liquids.
Ultrasonic dispersion does not require the use of emulsifiers. In many cases, ultrasonic emulsification can obtain particles below 1 μm. The formation of this emulsion is mainly the result of the strong cavitation of ultrasonic waves near the dispersion tool. The paraffin wax can be dispersed in water with a chemical agent, and the diameter of the dispersed particles is less than 1 μm.
The holding point of ultrasonic dispersion is usually small vibration and high acceleration. Ultrasonic dispersion devices have been widely used in food, fuel, new materials, chemicals, coatings and other fields.
Decentralization principle
1. Ultrasonic generator: its efficiency is as high as 90%, and it is small in size and light in weight; (also known as ultrasonic driving power supply).
2. Ultrasonic aiding system, in order to obtain high power, its resonant vibration frequency is selected at about 15kHz, the ultrasonic generator and the resonance system form a frequency automatic tracking system; (ultrasonic vibrator composed of ultrasonic transducer and ultrasonic horn ).
3. Ultrasonic dispersing tool; (the ultrasonic tool head is connected to the vibrator).
4. Dispersion container. The working principle of the homogenizer is that when the ultrasonic generator outputs high-frequency electric pressure to touch the ultrasonic actuator, after being amplified by the vibrator and the mechanical vibrating cap, under the action of the dispersing tool, a strong differential treatment is carried out in the container.
Influencing factors
Two factors determine the effect of dispersion: ultrasonic impact force; ultrasonic radiation time.
The outflow of the treatment liquid is Q, the gap is c, and the area of the plate in the opposite direction is S, then the average time t required for specific particles in the treatment liquid to pass through this space is: t=c*S/Q. To improve the ultrasonic dispersion effect, three elements must be controlled: the average pressure p of the treatment liquid, the gap c and the ultrasonic radiation time t(s).
Application range
Ultrasonic dispersion is widely used in many fields: such as food, cosmetics, medicine, chemistry, etc. The application of ultrasound in food dispersion can be roughly divided into three situations: liquid-liquid dispersion (emulsion), solid-liquid dispersion (suspension), and gas-liquid dispersion.
Solid-liquid dispersion (suspension): such as dispersion of powder emulsion, etc.
Gas-liquid dispersion: For example, the manufacture of carbonated drinking water can be improved by CO2 absorption method, so that the stability can be improved.
Liquid-liquid dispersion (emulsion): such as emulsifying ghee to make lactose; when making sauce, dispersing raw materials, etc.
Ultrasonic dispersion can also be used for the preparation of nanomaterials; for the detection and analysis of food samples, such as ultrasonic dispersion liquid phase microextraction technology