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cpp PROCESS ENGINEERING Modular, compact mill and classifier unit More flexibility in the lab In the chemical industry, especially where dry grinding is involved, well-appointed laboratories are a must today when developing new products, optimising processes or producing small samples. At this year’s Achema, Netzsch Trockenmahltechnik unveiled the Lab Compact Plus, a modular mill and classifier unit which is setting new benchmarks with its user-friendliness, compact design and flexibility. When designing the Lab Compact Plus, Netzsch considered typical laboratory conditions drawing on its own experience from decades of running a laboratory. The outcome: a plant with a stable, reproducible throughput and high product yield as well as production parameters that can be flexibly selected by the user. Thanks to the modular principle, five different systems can be installed in the machine’s swivel arm. They are easy to exchange using individual connector sets for electricity and compressed air. Amongst other things, the machine modules determine the final particle size and can be optimally adapted to the requirements of each particular product. Customers can choose between a fluidised bed jet mill, a high-density bed jet mill, a classifier mill, a fine classifier and last but not least a high-efficiency fine classifier, which Netzsch offers from a single source. Each of these components has been tested and optimised in conjunction with the Lab Compact Plus. For any specification The type of size reduction – and hence the selection of a suitable machine – depends mainly on the specified particle size, shape and size distribution. The downstream processing steps are a further factor, as is the amount of product to be ground. The deformation behaviour of the size reduction product, which can vary from brittle-elastic through inelastic or elastic-ductile to elastic-viscous, is another important criterion which influences the machine technology. Pictures: Netzsch The different machines can be installed on the basic module on the swivel arm easily and rapidly Jet grinding on a laboratory scale Defined fine grinding of even the hardest materials (up to 10 Mohs) with an exact upper particle size limit is possible using a CGS 10 fluidised bed jet mill, which combines an air jet mill with an integrated, dynamic air classifier. In the fluidised bed, which is fluidised by gas jets, particles are accelerated in an open jet and then impacted against other, slower particles on the way to or in the actual centre and hence ground. Grinding is completely autogenous and is therefore free of contamination. The 34 cpp 03-2018
Every child CGS 10 Fluidized Bed Jet Mill CONJET® 10 High Density Bed Jet Mill CSM 50 Classifier Mill CFS 5 Ultra-Fine Classifier is one of a kind and unique. Each child needs individual support according to their needs. Please help us by donating. Thank you! CFS 5 HD-S High-Efficiency Fine Classifier 0.1 1 10 100 1 000 10 000 Particle Size d 97 [μm] www.netzsch.com Ranges of fineness d 97 for laboratory mills and classifiers particles are transported to the classifier wheel by the gases ascending in the centre. The wheel rejects any particles which are too coarse, only allowing those whose size corresponds to the set parameters to pass through. The desired final fineness can be set by steplessly adjusting the speed of the classifier wheel and varying the amount of grinding gas. In the d 97 fineness range from 2.5 to 120 μm this proven grinding technology is suited for even tiny amounts of product on a laboratory scale. The Conjet 10 is the only laboratory-scale spiral jet mill featuring an integrated classifier which unites the advantages of a conventional spiral jet mill and a dynamic classifier wheel. This combination enables the Conjet 10 to achieve the highest finenesses and the steepest possible particle size distribution regardless of the product load, and therefore also higher throughputs. The adjustment of the grinding fineness via the product load – normally unavoidable with conventional spiral jet mills – is thus eliminated because the speed of the classifier wheel is settable. Thanks to the residue-free grinding and low build-up of deposits inside the machine, the Conjet is ideal even for high-value products. Impact grinding on a laboratory scale A fine impact mill is another option for producing finer final particles with a defined upper particle size limit if a dynamic air classifier is integrated in the grinding chamber housing. This can be achieved using a CSM 50 classifier mill. Grinding takes place between a peripheral grinding track and a grinding disc equipped with beaters. The impacted product particles are transported into the upper part of the machine by the classifier air which is supplied and then presented to the variable-speed classifier wheel. Depending on the set conditions (classifier speed, air volume), only appropriately fine particles pass through the classifier wheel. Finenesses ranging from 30 to 800 μm (d 97 ) can be realised with the classifier mill. Ultra-fine classification Due to their particle size distribution after a manufacturing or grinding process, some products are still not suitable for further use at this stage. Subsequent treatment is required for an exact particle size fraction, in order to optimise the desired product characteristics or to actually obtain them in the first place. Classification into particle size ranges >100 μm is usually achieved with screening machines. If particles
