Fast, Uniform and Reproducible Fluid Bed Drying
Product News Apr 28, 2011
Sherwood Scientific’s Model 501 programmable Fluid Bed Dryer provides a convenient lab scale method of rapid moisture reduction/removal at relatively low temperature. Multiple configurations and microprocessor control ensure complete flexibility for a wide range of applications.
The Model 501 Fluid Bed Dryer delivers a high air flow rate, breaking up wet samples and ensuring vigorous mixing so that drying is not only fast but uniform, with no lumps or caking of the particles.
Microprocessor control of the air flow, inlet air temperature and drying period, and a temperature/humidity probe within the tub assembly, enable all stages of the drying process to be programmed, monitored and analyzed.
Offering a maximum sample capacity of 5Kg, the Model 501 is compatible with both glass and stainless steel drying tubs of various volumes, and with a range of inlet and outlet filters and other accessories. This versatility makes it possible to dry hundreds of different sample types as well as carry out mixing, granulation and other processes.
The speed of fluid bed drying compared with conventional methods leads to faster sample testing and therefore production runs using a new material batch can be instigated sooner. Drying speed has proved a significant advantage for CIRES, a Portuguese company manufacturing PVC.
According to Luís Alves, Lab Technical Manager at CIRES, ‘We are using a Model 501 Fluid Bed Dryer to dry the PVC suspension cake in our lab, with very good results. Our material has a typical particle size distribution between 40 and 250 microns. Sometimes it is necessary to characterize our products before the drying stage in our plant. In the past we used an oven at 70ºC in order to dry the PVC slowly, with no ventilation to avoid contamination. However, this took a long time, usually 3 hours until the humidity decreased to acceptable values (<0.3%). Now, using the Sherwood FBD with a suitable mesh in the top cap and in the base, it is possible to dry the wet PVC (200g with 30% water) in only 40 minutes with 25% ventilation. Initially the material remains as a cake but within 10 minutes it becomes fluid, although the time necessary to dry the different PVC grades can vary significantly due to the different porosity and consequent water content.’
High reproducibility of the drying process and excellent homogeneity of the finished samples make the Model 501 ideal for studies of material drying behaviour, optimizing and scale-up of drying processes, and preparation of small sample batches for subsequent material studies.
In addition to applications in the manufacturing of plastics and gypsum, Sherwood Scientific’s Fluid Bed Dryer is also a valuable tool in the production of pharmaceuticals, food ingredients such as starch and yeast, and for drying agricultural seeds.