Technische Innovationen auf dem Wirbelschicht-und FlieÃbett-Gebiet
Prof. Dr. Kurt H. Bauer, Pharmazeutisches Institut der Albert-Ludwigs-UniversitÃ¤t, Freiburg/Brsg.
Fluidized-bed procedures are very successfully and on a broad basis in use in the pharmaceutical industry for about 75 years. From this point of view, it is not surprising if no greater or even revolutionary in-novations came up, apart from minor improvements, during the last decades. However, in the last few years, some novel devices worth to be mentioned were developed, those hence-forth will improve fluidized-bed processes. The main advantages, obtained by means of these new devices, consist in the elimination or reduction of some interference factors, like clogging of nozzles or filters, as well as in an optimisation of the motion of the materials to be processed. The results are increased production capacities, more safety, and a considerably better utilisation of the required energies. The following technical report informs about new ring-slot nozzle systems to obtain finest sprays, resp. smallest sprayed droplet sizes, as well as quite higher spraying rates, and reduced clogging properties. Further described innovations are booster bottoms, which are determined to the control of the inlet process air flows. These controlled air flows are able to convert the heterogeneously whirling or spouting fluidized beds into homogeneous fluidized-beds rolling over uniformly. The novel booster devices can be installed simply in conventional process containers in place of the normal screen bottoms. In this simple way, meaningly more homogeneous movements of the materials to be processed can be achieved. The third reported innovation con-cerns types of specifically folded outlet air filters made of metallic multi-layer textures. They are quite robust, highly efficient and easy to clean. These innovations are suitable to make in future fluidized-bed processes more economic and safer.
Â© ECV- Editio Cantor Verlag (Germany) 2000
pharmind 2000, Nr. 10, Seite 816