Ultrasonic Homogenizers-altrasonic.com

Ultrasonic Homogenizers

2020-07-31

Ultrasonic Homogenizers

Ultrasonic homogenizers are powerful tools to mix and homogenize solid-liquid and liquid-liquid suspensions. Ultrasonic homogenization is a mechanical process to reduce particles in a liquid so that they become uniformly small and evenly distributed.

Impact of Ultrasonic Homogenizers

When ultrasonic homogeizers are are used for applications such as mixing, dispersing and emulsifying, the objective is to reduce small particles or droplets in a liquid or slurry to improve uniformity and stability of the mixture. These particles (disperse phase) can be either solids or liquids. A reduction in the mean diameter of the particles increases the number of individual particles. This leads to a reduction of the average particle distance and increases the particle surface area. The graphic (click for larger view) shows the correlation between individual particle diameter and total surface area. Surface area and average particle distance can influence the rheology of a liquid. If there is a difference in specific gravity between the particles and the liquid, the homogeneity of the mixture can influence the stability of the dispersion.

If the particle size is similar for the majority of the particles, the tendency to agglomerate during settling or rising reduces, because the similar particles have a similar speed of rising or settling.

Ultrasonic homogenizers are very efficient for the reduction of soft and hard particles. The homogenization is based on cavitation. When liquids are exposed to intense ultrasonication, sound waves propagate through the liquid causing alternating high-pressure and low-pressure cycles (approx. 20000 cycles/sec.). During the low-pressure cycle, high-intensity small vacuum bubbles are created in the liquid, as the liquid vapor pressure is attained.

When the bubbles reach a certain size, they collapse violently during a high-pressure cycle. During this implosion very high pressures and high speed liquid jets are generated locally. The resulting currents and turbulences disrupt particle agglomerates and lead to violent collisions between individual particles.