FLOW-RATES FOR MILK AND CREAM IN PIPELINES

Milk fat globules destabilised by intensive shear strain during pumpin g and flowing often induce sensory defects in milk products. Milk and cream (4 to 45% fat) were sheared in a model system with Couette-flow conditions at various temperatures (5 to 20 degrees C) for 1 to 30 min to estabilish the critical rate which leads to fat globule damage. Lo wer critical shear rates were determined with increasing fat content, temperature as well as prolonged shear time. The results of the model experiment were transfered to pipe flow, tested and verified. The crit ical shear strain determined during experiments allow the calculation of flow rates for gentle pumping of milk and cream for various tube di ameters.