Disperse systems present in liquid or wet media are to be measured as suspensions, emulsions, gels or bubbles appropriate to the product. Due to the comparative ease of dispersion in liquid media, wet dispersion came into use well in advance of dry dispersion, and has been widely used for some time. During stirring and recirculation in wet reprocessing systems, often the resistance and inertia forces produced by the acceleration and flow of particles are sufficient to ensure consistent seperation of the primary particles in the dispersion medium. If necessary, dispersion is to be reinforced through treatment with ultrasound (cavitation forces) and the use of dispersants to stabilise the dispersion.
The optical concentration of a suspension or emulsion provided for measurement in a cuvette can be adapted for the relevant measurement process. To achieve this, there is the option of varying the liquid volume, or using cuvette types with different irradiation depths which determine the strength of the liquid film. In addition, continual agitation through stirring helps to maintain successful homogenisation and is a prerequisite for supplying a representative particle flow for reproducible measurements.