STUDY AND DEVELOPMENT OF A TEST METHOD FOR SPRAY BOOM SUSPENSIONS

Spray booms are equipped with suspensions to reduce the influence of boom movements and so minimize the non-uniformity of spray distributions on crops. The quality of suspensions can be estimated in terms of distribution regularity. Spray systems were tested on a track simulator which is able to reproduce ground irregularities under the wheels of a self-propelled vehicle. Boom positions were observed with an infra-red sensor and related to the simulated ground. Distribution patterns under a boom equipped with flat fan nozzles were investigated by measurements on a patternator. The effect of boom position was studied for height above the crop and boom tilt angle in the vertical plane. Heterogeneity of sprays from the same manufacturing series are an important factor in causing variations. Spray overlap was shown to modify the distribution pattern. A program was developed from these observations to compute a theoretical spray distribution pattern on soil. A map of volume distribution is drawn depending on boom movements, on tractor velocity and on spray parameters. Statistics and image analysis provide interpretation tools. Variations caused by boom movements are very important when compared with those caused by the nozzles themselves. The use of this set of tools for boom suspension testing is discussed. © 1994 Silsoe Research Institute.