Criteria for Optimizing Size and Configuration of Milk Pipelines

To verify various theoretical and practical aspects of milk flow, an experimental milk pipeline was used. Flow instability, characterized by a flooded section of pipeline (that is, formation of milk “slugs”), was dependent on pipeline configuration. Vacuum fluctuations from milk slugs as great fill depths characterized a looped configuration as 28.6 kPa were measured in a dead-end configuration. By contrast, stable flow over a wide range of flow rates, slopes, and. Manning's equation under stable flow conditions accurately predicted flow rate as a function of fill depth, slope, and pipe diameter. Milk Acid Degree Value was higher in milk subjected to slugging. An analysis of effective shear stress on milk suggests a range of fill depths for which milk quality might be maintained. A theoretical model is presented to predict pipeline milk flow as a function of number of cows and rate of unit attaching. A method for pipeline sizing is presented using this model, together with Manning's equation and suitable constraints for fill depth. Current recommendations for pipeline sizing may result in oversized pipeline diameters.