Mixing pasty products - Agitator performance

In recent years, agitation techniques have gone from being an art to a science. They are based on both theoretical and experimental considerations. Considerable progress has been made, thanks in particular to advances in experimental techniques (laser velocimetry, Particle Image Velocimetry PIV, tomography, ultrasonic techniques) and numerical techniques (Computational Fluid Dynamic CFD).

Generally speaking, in the food industry, a high-performance, optimal agitation system is very tricky to integrate into a production unit. This depends, of course, on the objectives of the unit operation. It may simply be a question of selecting the right agitation/mixing system for a new process, or, very often, of extrapolating the results obtained from an existing, but smaller-scale, production operation. A good knowledge of the process is essential to enable the most favorable choice to be made for the manufacturing operation, particularly in economic terms.

Proximity agitators seem to be the obvious choice for homogenizing pasty products. In this dossier, we propose to present the performance of the main proximity agitators used for pasty media, in terms of power consumption, mixing time, axial circulation and heat transfer. The effects of change of scale (extrapolation) on the main characteristic variables will then be reported, with particular attention paid to extrapolation of heat transfer, a fundamental issue in terms of food safety in the agri-food industries.

For more information on the various types of mixing equipment dealing with viscous fluids and their main characteristic variables, please refer to the previous dossier. .