Carlos Velázquez

Monitoring and control of a continuous tumble mixer

Abstract This chapter describes the powder mixing in the low shear tumble mixer, emphasizing the behavior of the powder inside the mixer vessel and the modeling of the batch and continuous case. The models presented focused on the concentration of the main ingredient of a powder blend and its distribution represented by the relative standard deviation. It also includes details of a continuous tumble mixer, control logics and the technology needed, software, sensors, and actuators, to control it. An example of the control of the main ingredient concentration and the total flow rate is presented. The results demonstrated that the continuous tumble mixer achieved acceptable homogenization of the powder blend and that it can be controlled adequately. However, blends of low dosage of the main ingredient required a different treatment and configuration of the control algorithm to achieve similar control performance.