Hardware and software design for premixing in-line injection system attached to variable-rate orchard sprayer

Authors: ZHANG, ZHIHONG - Kunming University Of Science And Technology; Zhu, Heping; HU, C - Texas A&M University

Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/6/2020
Publication Date: 7/1/2020
Citation: Zhang, Z., Zhu, H., Hu, C. 2020. Hardware and software design for premixing in-line injection system attached to variable-rate orchard sprayer. Transactions of the ASABE. 63(4): 823-831. https://doi.org/10.13031/trans.13730.
DOI: https://doi.org/10.13031/trans.13730

Interpretive Summary: Precision variable-rate spray technologies have advantages of significant reduction in pesticide waste and protection of ecological systems from chemical residues. Techniques of real-time in-line injection systems are needed to be part of the new technologies to solve pesticide exposure, tank mixture leftover and washed water disposal problems. In this research, hardware and software of a premixing in-line injection system were designed and assembled as an attachment to the laser-guided variable-rate orchard sprayers. A graphical user interface was integrated into the system for operators to manage and view the operation process on the touch screen. The system was designed to perform with loops in dispensing, mixing, and transferring desired amounts of water and chemical concentrates automatically to maintain spray mixtures with a constant concentration. Laboratory experiments illustrated that the simulated pesticide and water could be accurately dispensed into the injection line according to the concentration inputs and could be well mixed for variable-rate sprayers to discharge to target plants. This new premixing in-line injection system would be a potential technique to significantly reduce pesticide waste and improve environmental stewardship for both conventional and new precision variable-rate orchard sprayers.

Technical Abstract: To eliminate tank mixture leftover problems in pesticide applications, a premixing in-line injection system was designed as an attachment to a laser-guided variable-rate orchard sprayer. The primary components of the system consisted of a chemical metering pump, a water pump, a two-stage static mixer, a premixing tank, a buffer tank, an electric motor operated shut-off valve, a chemical container assembly, electronic control boards, a graphic user interface, and an embedded computer with a touch screen unit. Liquid level sensors were mounted in all tanks and the chemical container to control the fluid discharge process and prevent overflows. The graphical user interface with visual operation functions was designed for operators to communicate with the system and monitor the system operation status. During spray applications, the system was performed with loops in dispensing, mixing, and transferring desired amounts of water and chemical concentrates automatically to maintain spray mixtures with a constant concentration for variable-rate nozzles to discharge. The system was rinsed automatically when the spray application task was completed. In addition, the user interface was designed for operators to manage the system operation and view the operation status shown on the touch screen. Test results demonstrated that the simulated pesticide and water could be accurately delivered into the injection line and could be mixed well in the buffer tank before the spray mixture was discharged to the nozzles. The premixing in-line injection system would be a potential technique to further reduce pesticide waste and improve environmental stewardship for both conventional and new precision variable-rate orchard sprayers.