Design of VAV system of air assisted sprayer in orchard and experimental study

Cropping Systems

Orchards & Vineyards Orchards & Vineyards

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There is an urgent need for new development of pesticide application techniques and sprayers in Chinese orchard spraying, because of the requirements of environment pollution, food safety and operator exposure during application. One type of new automatic target detecting, based on canopy size with variable pesticide dosage and air-flow of air-assistant orchard sprayer, was developed to meet the demand of pest control in orchards, and is discussed in this paper. The techniques of automatic target detection, multi-sensors, electrostatics, and air-assisted spraying were combined within this system. Infrared sensors and a control unit were incorporated to automatically control the sprayer according to the target tree crop. The sensors detect the presence or absence of the target crop and automatically control the operation of the sprayer nozzles. When a target tree is detected it allows the nozzles to spray. When an interstitial space is detected between the trees, the sprayer will automatic stop spraying, the control units also adjust both the quantity of spray applied, and the air volume required from the fan according to tree canopy size. The system also allows the online recording of the date and canopy size at application. This lightweight highly efficient sprayer, reduces pesticide use and environment impact. To adjust the air flow according to the tree size, a series of previous experiments were studied. Experimental results showed that compared with changing the air inlet area, the air velocity could be changed by effectively changing the fan rotational velocity. The air flow will rise in a linear pattern as the fan rotation speed increases, as the simulation equation of Q=12.25N+3359.4. The air flow field tests indicated that air velocity increases with the increase in fan speed. The air velocity decreases irregularly as the distance from the center of the fan increase. The deposition uniformity of the tri-prism model is the best in the three models under the same condition.


Li LongLong; He XiongKui; Yao Qu; Song JianLi; Liu YaJia; Zeng AiJun
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Aspects of applied biology
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