Cleaning with Pulsed Flow

Cleaning of process equipment is a severe problem in food processing, especially in the dairy industry. On one hand economic reasons demand cost reduction and increasing efficiency throughout the manufacturing chain. On the other hand legal regulation and consumer awareness of hygienic hazards in foods require high standards in cleaning operations, process monitoring, staff training and documentation. This conflict of objectives has become more and more the subject of scientific research to work out reliable and efficient tools to provide nutritious, hygienically sound food at a proper price tag. One prominent field of research are cleaning in place operations (CIP), being the automatic cleaning of closed process equipment for the manufacturing of liquid and viscous foods.

The objective of this project is the enhancement of cleaning-in-place efficiency through pulsed flows and therefore the reduction of cleaning time and/or water and detergent quantities.

Pulsed flow describes the superposition of an oscillating flow on a steady flow component. Depending on certain flow parameters, the periodical change of flow velocity and wall shear stress yields an enhancement of deposit removal in closed process equipment, as several authors have already shown in lab-scale tests. Based on these findings, the project cuts down to the following tasks:

• Tests on the cleanability of basic elements in fluid mechanics comparing the results of steady flow and pulsed flow with a model soiling
• Examination of methods for the numerical simulation of pulsed flows in turbulent flow regimes
• Studies on the energy consumption of this cleaning method against the savings in cleaning time and the effective range in pipe systems on a close to industry standard prototype
• Verification of the findings by cleaning tests with whey protein soiling and industry like CIP-parameters