Newly Developed Low-pressure TeeJet Nozzles for Pesticide Application at Lower Water Volume and Reduced Wind Drift1

The development of TeeJet flat-jet nozzles in the 1960's has facilitated optimal herbicide application. The required accuracy of ± 15 % in transverse distribution was achieved by a nozzle spacing of 50 cm and a height above ground of 40-60 cm. Two problems remained: 1) to reduce volumes; 2)to limit drift yet further. The development of the low-pressure TeeJet has helped to solve these problems. The nozzle is constructed with a cylindrical tube which is ellipsoidal in cross-section at the input end and which narrows symmetrically to the axis to a flattened oval orifice at the output end. By this means 1) the spray angle of 110° can be achieved with a pressure of 1 bar; 2) better distribution is achieved at the edges of the jet, by comparison with the standard TeeJet; 3) a greater proportion of coarse droplets is achieved by comparison with 110° or 120° nozzles (nominal pressure 3 bar). It is accordingly possible to apply herbicides at volumes lower than the currently used 4001/ha. Trials have shown that, with few exceptions, water volume can simply be reduced to 1001/ha without any increased risk of drift