STP1430

    Pulse Width Modulated Sprays for Flow Rate and Droplet Size Control: Spray Dynamics and Field Performance

    Published: Jan 2003


      Format Pages Price  
    PDF (424K) 15 $25   ADD TO CART
    Complete Source PDF (3.8M) 15 $132   ADD TO CART


    Abstract

    Agrochemical application is made under the simultaneous demands of efficacious deposit, management of off-site movement including drift, and high time and labor productivity of the operation. Control of nozzle flow rate and droplet size provides the means to maintain efficacy while increasing productivity and reducing spray drift. Additionally, the maintenance of desired droplet size spectra while applying a variable rate prescription maintains the quality of the application job. Pulse width modulation is a technique that allows independent control of flow rate, droplet size and spray dynamics. Individual nozzles are controlled by dedicated solenoid valves closely coupled to the nozzle. The working range of rate control can be expanded to approximately 8:1, far beyond that of conventional pressure modulation. The technique has been integrated into an electronic control system for retrofit to existing rate control electronics. Laboratory and field testing has established the performance and utility of the design.

    Keywords:

    Droplet, size spectra, drift, variable rate, control, site-specific


    Author Information:

    Giles, DK
    Professor and Assoc. Development Engineer, University of California, Davis, CA

    Downey, D
    Professor and Assoc. Development Engineer, University of California, Davis, CA

    Kolb, T
    Field Engineers, Capstan Ag. Systems, Inc., Topeka, KS

    Grimm, JG
    Field Engineers, Capstan Ag. Systems, Inc., Topeka, KS


    Paper ID: STP11118S

    Committee/Subcommittee: E35.22

    DOI: 10.1520/STP11118S


    CrossRef ASTM International is a member of CrossRef.