Silverson has responded to industry demands for increasing standards of hygienic construction by developing a range of Ultra Hygienic equipment, including in-line mixers, top and bottom entry immersion/batch mixers and powder/liquid mixing systems.
The company says its high shear bottom entry mixers are increasingly specified by the pharmaceutical sector for applications where focused high shear in-tank mixing is required. The company offers a range of bottom entry mixers incorporating specific features, for example a minimal number of product contact parts, crevice-free design, electro-polished finish, and special hygienic shaft seals. Complete packages and data manuals including IQ/OQ documentation to comply with FDA and cGMP requirements are supplied.
The mixers can be used in conjunction with slow speed stirrer/scraper units. The rotor/stator workhead provides high shear that stirrer/scraper units cannot impart, while the stirrer/scraper unit complements this action by distributing the homogenised output of the bottom entry mixer uniformly throughout the vessel. This combination is ideal for high viscosity products, those that increase in viscosity on cooling and where heat-sensitive materials such as active ingredients may be added only at low temperatures. With lower viscosity products, bottom entry units can be used without any additional in-tank agitation. This eliminates the problems associated with immersed shafts and difficult-to-clean scraper blades, offering improvements in process hygiene, especially where large quantities of powder have to be dispersed into liquids using an in-tank mixer, the company says. Typical applications include the manufacture of vaccines and pharmaceutical suspensions.
A range of interchangeable workheads and screens is available for bottom entry units, allowing them to be adapted to perform a wide range of mixing tasks, including emulsifying, homogenising, disintegrating, dissolving, dispersing, suspending, particle size reduction, reaction acceleration and de-agglomerating. This makes them particularly suitable for r&d and pilot plant applications, says Silverson.
