Fluid-Bed Coating

• Published in: Encapsulated and Powdered Foods pp. 209 - 226
• Format: Book Chapter
• Language: English
• Published: United Kingdom CRC Press 2005; Taylor & Francis Group
• Subjects: Food & beverage technology; Fluid Bed; Wurster System; Coating Operation; Dry Coating; Fluid Bed Coating; Coating Material; Fluid Bed Coating Process; Continuous Fluid Bed; Side Spray; Batch Fluid Bed; Material Efficiency Improvement; Spray Drying; Coated Powder; Fluid Bed Process; Top Spray; Hot Melt; Bottom Spray; Cellulose Derivatives; Hot Melt Coating; Fluid Bed Coaters; Food Powder; Moisture Content; Air Suspension Coating; Interfacial Tension
• ISBN: 0824753275; 9780824753276
• DOI: 10.1201/9781420028300-11

I. Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197 II. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198 III. General Knowledge on Powder Coating and Fluid Bed . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198 IV. Theory of Fluidization and Fluid-Bed Coating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199A. Fluidization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199 B. Fluid-Bed Coating. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201V. Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203 A. Different Types of Fluid-Bed Coaters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2031. Top Spray Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203 2. Bottom Spray (Wurster) Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203 3. Rotor or Tangential Spray Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203B. Improvement of the Performance of the Fluid-Bed Coating Process . . . . . . . . . 204 1. Optimization by Material Efficiency Improvement (Hot Melt andDry Coating) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 2. Optimization by Design and Modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204C. Coated Powder Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205 D. Coating Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207 E. Guidelines for a Coating Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208VI. Continuous Fluid Bed for Food Powder Coating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 A. Single Bed Continuous Fluid Bed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 B. Horizontal Continuous Fluid Bed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 C. Multicell Continuous Fluid Beds for Coating. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210VII. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210I. SUMMARYThe chapter presents varied descriptions of the fluid-bed process for coating or air suspension coating, with an emphasis on the Wurster system (the most efficient batch fluid-bedENPO: “dk2963_c008” — 2005/3/19 — 08:28 — page 198 — #2apparatus), including a discussion on the application and the efficiency of batch fluid-bed systems and their improvement. An analysis of the performance of the batch fluid bed will show that the continuous fluid bed is the economically suitable solution for coating food powders and the schematic of the ideal continuous fluid bed for food powder coating is given as an indication. Phenomena involved in the process of coating fluidized solid particles are studied and some useful techniques to characterize and to evaluate the quality and the efficiency of the process are given and analyzed. Finally, a short classification of the most used coating materials in food and pharmaceutical industries is presented to give a quick view of what can be done with the technique.