Gentle dispersion in free fall
Dispersion in free fall is an option for dry, free flowing products, which do not tend to agglomerate. Especially coarser or sensitive powders and granules are gently dispersed when accelerated by gravity on their way into the measuring zone. Together with the sensors HELOS and QICPIC for laboratory applications and PICTIS for industrial applications, GRADIS offers particle size and particle shape analyses in a size range from a few micrometers up to 10 millimeters. Elongated or curled fibres may even be much longer.
This unit is ideal for products that do not need a high dispersing energy, like crystals, sand or granules. The 50 cm long fall shaft provides smooth dispersion and control and homogenizes the speed of the particles presented to the laser beam. GRADIS is fed by VIBRI/L, the software controlled feeding device for all dry dispersing sensors. GRADIS is typically operated together with an extraction unit for the particle collection and the generation of the laminar air flow. If required, the sample can be collected and re-used after the analysis.
GRADIS can be used for the analysis of very coarse particles and sample quantities up to the kilogram regime. The width of the outlet slit of the fall shaft can be manually set to 2 mm, 4 mm or 10 mm. This is used for image analysis application to keep the particles within the working distance of the imaging objectives. For very fine particles a centring unit with outlets of 1 and 0.5 mm is available. Particles up to 10 mm will be analysed with the 20 mm long fall shaft. The fall shaft can be separated into two halves for cleaning purposes. For special applications fall shafts with PTFE coatings (conducting or non-conducting) are available as an option.