ABSTRACT
Abbreviations ................................................................................................................................. 148 Unit Conversions ............................................................................................................................ 148 8.1 Introduction.......................................................................................................................... 148 8.2 History .................................................................................................................................. 149 8.3Process Description .............................................................................................................. 150 8.4 Conventional Pan-Coating .................................................................................................... 152
8.4.1Pan Design ................................................................................................................ 152 8.4.2 Ventilation................................................................................................................. 152 8.4.3Coating Delivery ....................................................................................................... 152 8.4.4Charging and Discharging ........................................................................................ 153
8.5 Vented Pan-Coating .............................................................................................................. 153 8.5.1Pan Design ................................................................................................................ 153 8.5.2 Ventilation................................................................................................................. 153 8.5.3Spray Guns ................................................................................................................ 155 8.5.4Exhaust Filter ............................................................................................................ 156 8.5.5 Charging and Discharging ........................................................................................ 156
8.6Critical Parameters ............................................................................................................... 156 8.6.1 Charge ....................................................................................................................... 156 8.6.2Pan Speed ................................................................................................................. 157 8.6.3 Process Air ............................................................................................................... 158 8.6.4 Temperature .............................................................................................................. 158 8.6.5Gun Position ............................................................................................................. 158 8.6.6Spray Rate ................................................................................................................. 159 8.6.7Atomizing and Pattern Air ....................................................................................... 164 8.6.8Process Endpoint ...................................................................................................... 165
8.7 Scale-Up ............................................................................................................................... 167 8.7.1 Charge ....................................................................................................................... 167 8.7.2Pan Speed ................................................................................................................. 168 8.7.3Process Air ............................................................................................................... 168 8.7.4Spray Rate ................................................................................................................. 169 8.7.5 Atomizing and Pattern Air ....................................................................................... 170
8.8 Applications .......................................................................................................................... 172 8.8.1Coating Materials..................................................................................................... 172 8.8.2Conventional Pan-Coating Applications .................................................................. 173 8.8.3Vented Pan-Coating .................................................................................................. 173
8.9 Troubleshooting .................................................................................................................... 173 8.10 Conclusions ........................................................................................................................... 175 References ...................................................................................................................................... 175
°C degrees Centigrade cmcentimeters °Fdegrees Fahrenheit Ftfeet or foot Ggravitational force g gram in. inch kg kilogram L liter lb pound LEL lower Explosive Limit minminute mm millimeter psipounds per square inch UELupper Explosive Limit
°C = (°F − 32)/1.8 1 in. = 2.54 cm 1 m = 3.28 ft
Pan-coating refers to processes where solid particulate materials or tablets generally ranging from near a few mm to several centimeters in diameter or size are placed in a rotating drum where they recirculate as coating material is applied from solution or suspension. Drying air is passed through or over the bed in some manner to evaporate the solvent vehicle and deposit coating on the particles. Pans are commonly tted with angled “bafes” or “blades” and/or antislip “bars” on the inside surface to optimize particle circulation and coating uniformity.
