Effects of a Hydraulic Pressure System and Grooved Rollers on an In-Field Sweet Sorghum Press

Abstract

The specific objectives of this study were to redesign the rollers of an in-field sweet sorghum press for better grip on stalks and better juicing efficiency, implement a system to allow rollers to move vertically to prevent plugging, and compare the efficiencies of the redesigned and original rollers. The new rollers were designed based on sugar milling technology. A hydraulic pressure system was designed and implemented to allow vertical movement of two of the top rollers. Projected pressure levels of 0, 1.5, 3, and 4.5 MPa were chosen for evaluation. Several pressure combinations were evaluated with each roller type, but not all combinations could be evaluated due to plugging and time constraints. The treatments were compared using the Ryan-Einot-Gabriel-Welsch and LSD multiple comparison tests in SAS ®. Improvements in throughput of sweet sorghum stalks were observed when using grooved rollers with the hydraulic pressure system. Stalk grip was improved, and plugging was observed less frequently. When plugging did occur, it was less severe than that which occurred using the original design of the press. The statistical analysis of the treatment efficiencies showed that the optimum operating point for grooved rollers was a uniform projected pressure of 3 MPa. This resulted in a juicing efficiency of 43.2%. This treatment was in the top statistical efficiency group and had a lower power requirement than the other treatments in this group. Similar efficiencies were observed with smooth rollers, but these rollers had poor throughput characteristics.