Research of an appropriate inert compound to use as an alternative to the granules of the plant protection products in the inspections of microgranulators

Abstract

The goal of this experimentation was to find an appropriate inert and hydrophobic compound with physical-dimensional properties as close as possible to those of the granules of the plant protection products (particle size: 0,3-1,2 mm and density: 0,6-1,4 g/cm3) in order to allow the micro granulator periodical inspection following the incoming SPISE Advice related to this aspect. In addition, the inert should be also commercially available guarantee for a long time and not abrasive. During the test, four inert materials were analysed: corn flour, rubber granules, glass microspheres, and plastic granules.
Tests were performed in the laboratory using a specific device in order to drive the micro granulators. For each regulation, it was measured the amount of outlet every two rotations of the metering unit drive shaft, up to a maximum of 10 rotations (2, 4, 6, 8, 10). Moreover, It has been detected also the time every two rotation.
Tests have highlighted a good repeatability with all tested materials independently of the number of rotations or the rotation time of the metering unit drive shaft (CV max = 6% for corn flour, glass microspheres and plastic granules; CV max = 5% for rubber granules). In addition, a good linearity in relation with metering unit regulation, independently of the materials and the number of rotations, was pointed out. Considering that the rubber granules are hydrophobic (they are not Influenced by relative humidity of the air or by water) and show a low cost (about 2-3,00 €/kg), this material seems the more suitable inert compound , between those tested to be use in the periodical mandatory inspections of micro granulators.