Wiegel D.,Anhalt University of Applied Sciences |
Eckardt G.,Parsum GmbH |
Priese F.,Salutas Pharma GmbH |
Wolf B.,Anhalt University of Applied Sciences
Powder Technology | Year: 2016
Particle size and particle size distribution are measured in-line in fluidized bed processes. Coating processes demand detection of the particle growth and the timely recognition of undesirable agglomeration for process intervention and process parameter change. The aim was the detection of agglomerates (large particles) in lots of small particles. Therefore spiking trials with pellets of microcrystalline cellulose were performed. The blends were fluidized in a fluidized bed apparatus and particle size was measured in-line by Spatial Filter Velocimetry method. Snapshots of volume density distribution and number density distribution at distinct moments of the process were registered, and finally the density distributions were averaged over the whole process time. Agglomeration was unequivocal detected by volume density distribution. In contrast the number density distribution was not suitable to detect low absolute numbers of large particles in the blends. In real fluidized bed coating processes with pellets and model substances, median particle size values x10,3; x50,3 and x90,3 were measured versus process time. Median values increase continuously with process time under optimized process conditions. Due to worst case conditions, caused by super-wetting of the fluidized bed, Agglomerates were generated and detected by a non-linear increase of the x90,3-time-plot (greater storage of large particles). Also snapshots of volume density distribution under worst case process conditions indicate clearly the formation of agglomerates. The in-line particle size measurement at fluidized bed coating is a useful Process Analytical Tool (PAT) in the process control. © 2016 Elsevier B.V.
Dieter P.,TU Chemnitz |
Stefan D.,Parsum GmbH |
Gunter E.,Parsum GmbH |
Michael K.,Parsum GmbH
Advanced Powder Technology | Year: 2011
Sizing of particles in industrial processes is of great technical interest and therefore different physical-based techniques have been developed. The objective of this study was to review the characteristics of modern sizing instruments based on a modified fibre-optical spatial filtering technique (SFT). Fibre-optical spatial filtering velocimetry was modified by fibre-optical spot scanning in order to determine simultaneously the size and the velocity of particles. Sizing in-line instruments of Parsum GmbH use these measuring principles and may be adapted to different process conditions. Particles with sizes of 50-6000 μm and velocities up to 50 m/s may be measured by the probe system IPP 70. An overview is given to real-time sizing of particles in different technical applications: fluid-bed granulation, high shear wet granulation, Wurster coating, mixing, spray drying, crystallization and milling. © 2011 The Society of Powder Technology Japan.
Petrak D.,TU Chemnitz |
Dietrich S.,Parsum GmbH |
Eckardt G.,Parsum GmbH |
Kohler M.,Parsum GmbH
Powder Technology | Year: 2015
Some in-process two-dimensional particle sizing methods can provide on-line information about the chord length distribution of a population of particles. The objective of this study is to use the chord measurement not only for the size determination but also for the determination of the particle shape. Main results are the non-dimensional aspect ratio or the roundness of the particle. The elongation values can be calculated by three non-dimensional parameters which are derived from the mean, mode or maximal chord length of the number and area based chord distributions. The application of these shape parameters is limited to narrow particle size and shape distributions. The application is demonstrated for coating of elliptical seed particles and spherical pellets (Cellets®1000). An optical probe system (IPP 70, Parsum GmbH, Germany) was used for the measurement of chord lengths during the coating processes. Results of an image analysis were in a good correlation with the results of the chord measurements. The advantage is the simultaneous use of the measured chord lengths for the characterization of the particle size and also the particle shape without any need for additional measurement equipment. Another advantage is the in-line determination of the particle shape without taking a powder sample. © 2015 Elsevier B.V.