Experimental determination of flow concentration for pneumatic conveying systems of air-seeders

International audienceTaking into account the complexity of wide width air-seeders, they remain less studied. The chief point for air-seeder designers is conception of the pneumatic conveying system. It must be precise in terms of uniformity so that that the agro-technical goals should be achieved. It must also ensure high rates without causing damages to seeds. This paper provides a theoretical analysis of pneumatic conveying designing applied to air-seeders. It shows that the conveying of particles (seeds, fertilizers or their mixture) in a given pipe depends on two interconnected parameters: flow concentration and air velocity. The knowledge of these two parameters is a necessity for the design of conveying systems but they are not defined in the case of agricultural machinery. This paper proposes a method to measure the flow concentration and the air velocity values which must be used to optimize an existing seeder (relatively to machine's outflow) or to design a new pneumatic seeder. In this case choices about pipes' diameters in each part of conveying system can be optimized from an energy point of view and this paper presents how the collected values can be used in a global methodology of design for air-seeders' conveying system