Development and experiment of riser air-blowing sprayer in vineyard

For avoiding pesticide waste due to uneven spraying volume distribution of the traditional axial mist sprayer, riser air-blowing vineyard sprayer was developed which took small four-wheel tractors as power. Through the variable power takeoff installed in the left of the speed change box in tractor, the riser air-blowing vineyard sprayer transferred the power from tractor to rear plunger pump and centrifugal blower. When the airflow blown by the centrifugal blower was blown through air outlet of wind-cone installed both sides of the vertical spray rack, it can not only prevent the droplet drifting, but also atomize the droplet and increase the penetration of the droplet in the grapes. Because of different vineyard row distances, adjustable spray frame structure was designed. It is connected by three segments of square steel tubes which was adjustable and had a series of holes. Through the adjustable spray frame structure, the spray distance of sprayer was from 800 mm to 1 600 mm. The indoor and field experiments of prototype were done to test the anti-floating performance, secondary atomization performance of vertical wind-cane structure and adhesive rate of droplet in crown. The experimental results indicated that when the natural wind speed was 3.5 to 4.5 m/s and the air speed of duct outlet was 30 and 35 m/s, the pesticide drift was reduced, the deposition were increased, the volume median diameter(VMD)of the droplets were less than 150μm, the diffusion ratio(DR)of the droplets was more than 0.74, and the secondary atomization performance was better. The droplet adhesion rate in leaves on positive and negative sides inside the trees reached 70.22% and 30.21% respectively, and that on leaves of positive and negative sides outside the trees reached 85.69% and 49.36% respectively when the distance between the nozzle and the tree was 30 cm, the speed of the tractor was 1.5 m/s, the pressure of plunger pump for sprayer was 0.25 MPa, the speed of the fan was 2 500 r/min. These parameters meet the requirement.