The Effect of Different Percent Liquid Addition and Wet Mix Time with Different Liquid Mix Cycle Time Setting on Uniformity of Mix

The liquid addition system is often designed to add liquid ingredients with the shortest application time in order to increase the batching capacity of the mixing process. The amount of liquid that is added into the mixer could affect the batch cycle time, especially, when there is a set wet mix time. The two most common settings in automated control systems are fixed total liquid mix time (liquid addition plus a wet mix time) and fixed wet mix time. The fixed total liquid mix time starts when a liquid pump is activated to add the liquid, whereas the fixed wet mix time setting starts after the liquid pumps stop. However, there is no data to determine which type of automated control system produces a uniform mix of liquid to dry feed. The objective of the experiments was to determine the effect of percent liquid addition, wet mix time and liquid mix cycle time setting on the uniformity of mix. Treatments were arranged in a 2 × 3 factorial: Experiment 1 treatments were fixed wet mix time (45 and 60 s) and percent liquid addition (1.14%, 2.27% and 3.41%); and Experiment 2 treatments were fixed total liquid mix time (45 and 60 s) after liquid addition and percent liquid addition (1.14%, 2.27% and 3.41%). The results of Experiment 1 indicated the 45 s fixed wet mix time had a significantly higher %CV as compared to the 60 s fixed wet mix time (P=0.0467) but there was no interaction between fixed wet mix time and percent addition of NaCl solution (P=0.5114). The results of Experiment 2 indicated an interaction between the percent addition of NaCl solution and the fixed total liquid mix time (P=0.0221), and both percent addition of NaCl solution and fixed total liquid mix time affected the %CV treatment (P<0.0001 and P=0.0002, respectively). The results of these experiments demonstrated that the liquid addition time and the percent of liquid addition affected the uniformity of mix. The uniformity of liquid application should be tested with the highest percent liquid addition.