Gentle treatment for free-flowing products
Fast but gentle mixing or thermal treatment for free-flowing pharmaceutical products is claimed for a new mixer/dryer from Krauss-Maffei Process Technology UK, thanks to the conical screw mixer action that creates virtually no friction between the screw and the vessel wall. Product is delivered upward by the screw and circulated back to the centre of the vessel for thorough mixing with minimal risk of lump formation. The machine is available in both top and bottom drive versions, but the bottom drive configuration with an innovative compact design drive arrangement makes the mixer particularly suitable for applications where space is restricted.
The wall of the vacuum-tight vessel and the mixer screw can be heated by water, steam or thermal oil to a contact temperature of 200oC. This gentle, low temperature contact drying is energy efficient and protects the products within the vessel.
Another feature is a new design of dry running conical mechanical seal to the bottom drive that eliminates the risk of contamination by lubricating fluids, the company says. In addition, the conical sealing surface means that the area of the PTFE ring in contact with the product is kept to a minimum. The area above the seal is open so that there are no critical areas for product build-up and simplifying cleaning. The sealing cartridge can be disassembled as a single unit to the bottom to reduce downtime.