When active ingredients are synthesised in the production of pesticides or the manufacture of pharmaceuticals, the consistency of the product frequently changes during the mixing and drying process. Plant systems that also process different active ingredients must therefore demonstrate a high degree of flexibility.This requirement can be fulfilled using a mixer-dryer or reactor that amixon has developed and produced for a well-known manufacturer of pesticides. The system can process mixtures with dusty, flaky and powdery consistencies equally as well as pasty, sludgy or viscous products. This is particularly important in the case of high-performance mixer-dryers, since viscoplastic phases are an integral part of many drying processes. A typical example is the transition from a pumpable suspended mass to a viscoplastic, rubber-like substance. As the liquid phase product is reduced, the mixture first becomes crumbly and granular, then powdery and free-flowing.
Combination of mixing and drying
For successful synthesis, the essential process steps must take place during the liquid phase. As part of multi-step manufacturing, different liquids are used in each case for rinsing and extracting. The conversion to powder takes place during the last synthesis step by means of contact drying. The need for flexibility is also met with regard to the mixing process: the machine is suitable for both the careful homogenisation of the mixture as well as for more intensive deagglomeration. In order to prevent unwanted reactions and to ensure a consistent level of quality, the process is carried out in a fine vacuum of 0.1 Torr (0.133 mbar). This flexibility also applies to the quantities that are mixed and dried. The reactor provides consistently high mixing quality with filling levels from 10 to 100 %. Thanks to the SinConvex mixing tool developed and patented by amixon, an exceptionally high degree of residue emptying is possible when changing products.
Superior mixing quality for a variety of filling levels
In order to achieve this, the outer contour of the mixer is shaped like a sinusoidal curve. The mixture is conveyed upwards along the wall of the vessel and flows downwards in the centre of the container. This geometry ensures that all of the mixture flows to the base of the container during emptying. The vacuum mixer-dryer produces high-purity active ingredients. The mixing device is driven only from above and can be fully heated. The shaft seals of the mixing device shaft and the cutting rotor are implemented as face seals. In addition, the sealing valve at the end of the mixing chamber cone, which operates without dead spaces, is extremely gastight.
Developed to meet the highest requirements
The mixing chamber of the reactor was manufactured using Hastelloy C 22. As well as offering high strength, this material is also resistant to corrosion. The entire system was manufactured in accordance with the principles of Good Manufacturing Practice (GMP) and in line with the requirements of the FDA. All qualification steps were performed in accordance with GMP. The complete documentation of development, manufacturing and commissioning also meets the stringent requirements of the pharmaceutical industry.hall 6.0 booth C76
