Particle sizing in real-time with on-line laser diffraction for dry powders ranging from 0.25 µm to 1,750 µm in a downpipe
Together with the compact mini SCREWSAMPLER, the laser diffraction sensor MYTOS forms a robust on-line process analysis system. The screw sampler is integrated in a downpipe, where it conveys a representative cross-section of the product stream out of the process line and feeds it directly to the particle size analysis. Thanks to the use of the integrated RODOS dry dispersion in the MYTOS system even finest, cohesive powders can be reliably dispersed and measured. The interplay between sampling, dispersion and laser diffraction sensing enables real-time analyses of dry powders and granules with particle sizes ranging from 0.25 µm to 1,750 µm. Likewise, products with a broad particle size distribution or processes with an inhomogeneous product stream are representatively sampled. The recording of measured data under process-related conditions supports integrated quality inspection and optimised process control.
The compact screw sampler can be easily integrated in the product-carrying downpipe with a DN25 butt welded ferrule with an installation height of just 30 mm. The immersion depth of the screw can be adjusted between 200 mm and 300 mm depending on the cross-section of the pipe to be sampled. Thanks to the openings in the sample collection tube in which the screw runs, a representative cross-sectional sample of the free-falling particles is obtained. Prior to sampling, the screw runs in reverse gear for self-cleaning and empties the product that was collected between two measurements back into the product stream. The rotational speed and the runtime of the screw are adapted to the product and to the process conditions in order to obtain the optimum sample amount. In downpipes with typical throughputs ranging from 1 kg/h to over 1 t/h, it usually takes just a few seconds to obtain a representative analysis sample of approx. 2 g to 5 g. In order to optimise the sample extraction – e.g. for powders with poor flowing properties – it is also possible to assist the particle transport with aspirated secondary air or with optionally supplied compressed air. Screws are optionally available made of polyamide or stainless steel.
- Particle size and particle size distribution
- For dry, fine to coarse grained, also cohesive powders and granules
- For product temperatures from -20°C to 80°C
- For real-time analyses on a product-carrying downpipe | on-line
- 5 high-resolution measuring ranges from 0.25 µm to 1,750 µm | R2 to R6M
- Compact screw sampling in the downpipe | Installation height 30 mm
- Sampling of a representative cross-section from the product mass flow
- on-line measurement outside the process line under process-related conditions
- Connection to process control systems | TCP/IP, OPC, Modbus®, Profibus®, PLC signals
- Monitoring of multiple process lines with a single sensor | Multiplex installation
All on-line systems can be optionally equipped with a manual sample feed, which comprises the vibratory feeder VIBRI and a stainless steel hopper. The systems are equipped with a VIBRI platform and the corresponding connections as standard. The hopper is mounted with a clamp connection onto the sensor system in place of the hose line of the sampler. This upgrade enables manual off-line measurements and is also required for re-certification of the systems with reference material.
In cases where particle size needs to be monitored on multiple process lines, the capturing of measurement data can be done with just one MYTOS laser diffraction system and multiple samplers installed in the different lines. Sequential sampling provides the sensor with samples from the different lines one after the other via a collector. Fast measurement and cleaning cycles effectively prevent the risk of cross-contamination during processing of the individual samples from different origins.
