Mateo Ortiz, Daniel

Profile Picture

Filters

20141
Reset filters

Settings

Citations

Publication Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    Publication
    Particle flow promoted by external forces in a confined space – feed frame case
    (2014) Mateo Ortiz, Daniel; Méndez Román, Rafael; College of Engineering; Cardona Martínez, Nelson; Cordova, Ubaldo; Romañach, Rodolfo; Department of Chemical Engineering; Ortíz, Juan A.
    Pharmaceutical tablets are the most sold and preferred drug solid dosage form due to its many advantages. The feed frame was designed to transfer the powder from the hopper to the tablet press dies as the die disk rotates. The die filling process is complex and dynamic and entails different stages that present distinctive features. A proper understanding of the feed frame system is important to reduce or avoid possible problems during tablet manufacturing and to accomplish a successful tablet processing. For these reasons, this dissertation aims to provide a fundamental and practical understanding of particle flow in a confined space while applying external forces. It also develops a fundamental mathematical model to describe the force exerted by the paddles. This is needed to optimize the operation of feed frames that are used to ensure uniform filling of tablet press dies. To obtain an in-depth understanding of powder flow inside the feed frame, the Discrete Element Method (DEM) was used. The objective was to study the paddle wheel and die disk speed effect on particle size segregation inside the feed frame and dies. The results show that particle size segregation can occur during the die filling process. Paddle wheel speed was demonstrated to be the most important factor to control top to bottom segregation inside the feed frame. Another study was developed to correlate powder attrition and overlubrication with experimental and numerical residence time distribution (RTD) data. A correlation between particle size and force applied to particles was developed using DEM. The results show that paddle wheel speed, die disk speed, exit contributions and outlet mass flowrate have an effect on RTD. Near infrared spectroscopy (NIR) was used to monitor the powder flow and to complement its understanding during the die filling process. The different factors that could affect the prediction of the developed NIR calibration models were studied. The results show that NIR spectra can help in the understanding of powder flow inside the feed frame. It was demonstrated that the content uniformity can be assessed with high accuracy during the die filling process.