TABLE OF CONTENTS For process scale operations it is normal for users to pack stationary phases in their own column hardware. The most common equipment available is based on the dynamic axial compression system invented by Couillard [4.1], subsequently assigned to, and first marketed by Prochrom (now NovaSep). The original patents on this technology have now expired so this type of column format is now available from a range of suppliers. In general, this simple but very effective technology involves the use of a moving piston as one of the column end fittings thereby allowing a constant compression of the packed bed with a dynamic removal of column voids. Examples of preparative DAC columns and HPLC systems are found in Figures 4.1 and 4.2. Figure 4.1 shows a 20 cm diameter DAC column, which can be seen on the left of the photograph. Figure 4.2 shows an industrial scale column with an internal diameter of 60 cm.
Other column designs have been developed, including radial compression [4.2] and annular expansion [4.3]. The radial compression system originally developed by Waters, and now marketed by Biotage, uses flexible polymeric cartridges packed with stationary phase. The cartridge is housed in a cylinder and the axial compression is generated by applying external pressure to the cartridge. In the annular expansion columns a tapered rod runs through the column and compresses the stationary phase against...
