Fertilizer throwing device for spreading an air-dust mixture with the use of compressed air

The fertilizer throwing device for spreading an air-dust mixture with the use of compressed air achieves - by comparison with existing units - a substantial increase in throwing distance for the pulverulent fertilizer material. The fertilizer dust is passed by means of compressed air provided by a compressor 18 out of the tank of a road tanker 1 via a flexible hose 13 to a pivoting throwing pipe 2. The throwing pipe 2 is subdivided into a cylindrical feed pipe 3, a mixing nozzle 4 and a linear acceleration pipe 5. The invention is notable for the fact that the dust-air mixture is accelerated to supersonic speed in the mixing nozzle 2, the smaller dust particles following the air very effectively while the larger dust particles initially remain behind and catch up in the subsequent acceleration pipe 5, so that a generally higher level of velocity - as the basis for a long throwing distance - is achieved at the outlet of the throwing pipe. A further improvement is possible by blowing additional compressed air into the throwing pipe 2. Excess air from the first compressor or conveying air from a second compressor is blown in at the throwing pipe via air feed nozzles 6, 7 and 8. Because of its lower density, the pure added air is accelerated better, and energy is thus introduced into the mixture, which is expressed in a higher exit velocity from the throwing pipe 2 and a further increase in throwing distance.