Estimation of two-dimensional fertiliser mass flow distributions by recording granule impacts

EA EcolDur CT1International audienceThis paper presents a new method to simultaneously measure the horizontal and verticaldistributions of the mass flow in the vicinity of the spinning disc of a centrifugal fertiliserspreader. The method consists in recording granule impacts on a cylindrical vertical screenplaced around the disc. The screen is covered with a paper band, a carbon film and aprotective coat, so that granule shocks against the screen produce impact marks on therecording paper band. A mathematical model is used to estimate the local impact density bycorrecting the bias due to impact overlapping. Algorithms are here developed to process therecording band, taking into account its location with respect to the spreading device. Thedistribution of the mass flow is studied for two fertilisers. Our findings demonstrate thatprocessing impact record clearly distinguishes the horizontal and vertical distributions of themass flow for a compound fertiliser NPK and potassium chloride. For the horizontaldistribution, comparisons are carried out with results deduced from a traditionalcompartmented ring. The vertical distribution of the mass flow is also studied. This newapproach paves the way for the design of alternative tests and diagnostic tools to characterisecentrifugal fertiliser spreading