BASICS FROM OUR TECHNOLOGY


DISPERSING

Dispersing is the actual generic term for work, which is executed using rotor/stator units. It is also referred to as "wet grinding". The main task of rotor/stator dispersers is crushing, mixing or foaming of different components to evenly distribute them. The resulting dispersions, emulsions, suspensions and foams are used in the pharmaceutical, chemical, food, life science and cosmetics industry.

The following material systems can be processed using these rotor/stator generators:

LIQUID-SOLID / LIQUID-LIQUID/ LIQUID-GASEOUS


ROTOR/STATOR

The Rotor is the rotating part of the generator. As it rotates within the stator, a vortex is created, which sucks the product to be processed into the generator or working zone. In this process, the product is accelerated axially and pushed to the outside through the tooth apertures of the stator by centrifugal force.


THE PRINCIPLE

Rotor and stator intermesh coaxially. Driven by a high-performance motor, the rotor generates vacuum, which continuously sucks in the phases to be dispersed. The phases to be dispersed are accelerated centrifugally in the working range of the rotor/stator before they reach the shear gap between rotor and stator. The product is subject to high deceleration-tangential and radial acceleration forces. The individual particles/droplets are torn apart and thus reduced in size. This is called shearing. In this process, circumferential speeds of up to 50 m/s can be reached. The particles/droplets are reduced further in size through additional cutting and crashing effects. These extreme turbulences that are caused during processing provide for excellent homogenization of the product!


FINAL FINENESS OF AN EMULSION/SUSPENSION

Decisive for the fineness of an emulsion / suspension is the following: The selection of an adequate dispersing generator (rotor/stator), the distance between rotor and stator (300 to 500 microns standard),  the correct circumferential speed.


HOMOGENIZATION

Two or more product phases are distributed evenly so that exactly the same distribution is established in each partial quantity.


EMULSIFYING

Two liquids that cannot be mixed stably, a hydrophobic (e.g. oil) and a hydrophilic (e.g. water) phase, are mixed with each other permanently. In order to get a stable emulsion the total surface of drops is required to be as large as possible (this can only be achieved by very small drops) and an emulsifier and possibly a stabilizer are required as well. (e.g. skin cream).


SUSPENDING

This term relates to the distribution of an insoluble solid material in a liquid. In many cases, suspending requires high turbulences and special generator geometries (e.g. color particles together with the carrier liquid).


DISSOLVING

In this process, soluble materials should be introduced into a liquid. This is usually achieved by high turbulences relating to the speed of the dissolution process.


DESAGGLOMERATION

Dry particles (e.g. in powder) become lumpy and form agglomerates when mixed with liquids. These agglomerates are smashed mechanically during dispersing.


ACCELERATION OF REACTIONS

The mechanical effect of the rotor / stator accelerates reactions.


SLURRYING

Due to the specific weight of certain solid materials, the suspension disintegrates after a certain period. Heavy particles form sediment by sedimentation. This sediment is swirled up by turbulences in order to restore the mixture.


FOAMING

Foaming relates to the introduction and homogeneous distribution (dispersion) of air in liquid. Gas bubbles are also reduced in size through high shearing forces (rotor/stator), which results in a more stable foam.