Technical Note: Packing Factors of Feed Products in Storage Structures

Experiments were conducted to measure the changes in bulk density of cracked corn, corn meal, soybean meal, cotton seed meal, and distillers dried grain (without solubles) when subjected to simulated overburden pressures. All materials were tested at two moisture content levels (approximately 8% and 12% w.b.) and seven pressures between 0 and 69 kPa (0 and 10 psi). A mathematical model was fitted to the data to predict the bulk density of each feed ingredient as a function of pressure and moisture content. These relationships were inserted into a previously developed computer model to predict ingredient packing within conventional storage structures based on Janssen's equation as a function of feed product type, moisture content of the material, friction characteristics of the bin wall material, material height, and bin diameter. Cracked corn experienced the smallest amount of packing (approximately 4.3% in a bin with a diameter of 1.8 m and a height of 1.8 m), while distillers dried grain (without solubles) had approximately 8.1% packing in the same sized bin. With a bin diameter of 5.5 m and a height of 5.5 m, distillers dried grain (without solubles) and cracked corn had a packing factor of 13.3% and 6.8%, respectively. As moisture content increased the amount of packing increased for all materials. The data presented can be used for inventory control and management.