As-applied estimation of volumetric flow rate from a single sprayer nozzle series using water-sensitive spray cards

M. P. Sama, J. T. Evans, A. P. Turner, S. S. Dasika

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

The objective of this study was to test the feasibility of using coverage measurements from water-sensitive spray cards to estimate the volumetric flow rate at an individual sprayer nozzle. TeeJet VisiFlow Even Flat Spray Tips were selected due to their uniform distribution of coverage. Spray distribution for each nozzle was validated using a spray patternator table with 2.5 cm sampling widths. A rotary test fixture translated water-sensitive spray cards through the spray dispersion (water at ambient conditions) at a constant angular velocity and a radius of 1.2 m. The test fixture measured volumetric flow and pressure at the nozzle and recorded data at a rate of 10 Hz. A helical gear pump and a pistontype pressure regulating valve were used to provide constant pressure. The first experiment fixed the test fixture speed at 3.14 rad s-1 and used varying pressures from 70 to 552 kPa (10 to 80 psi) in 70 kPa (10 psi) increments. First-order and second-order regression models were developed for the nozzle series, and validation data were collected at intermediate pressures to test the ability of the model to predict volumetric flow rates. The second experiment fixed the system pressure at 310 kPa (45 psi) and varied the speed of the test fixture at seven increments between 2.0 and 3.8 rad s-1. Spray cards were digitized using a scanner and processed for coverage using the MATLAB image processing toolbox. Results showed that the accuracy of the spray card method was within 1% full-scale of a commercial impeller flowmeter for a single series of nozzles moving at constant speed. Varying speed could be accounted for but required knowledge of the individual nozzle model. The method demonstrated in this study may be useful for field validation of variable-rate control systems on agricultural sprayers.

Original languageEnglish
Pages (from-to)861-869
Number of pages9
JournalTransactions of the ASABE
Volume59
Issue number3
DOIs
StatePublished - 2016

Bibliographical note

Funding Information:
This material is based on work supported by the USDA National Institute of Food and Agriculture and the Kentucky Agricultural Experiment Station under Agreement KY005038.

Keywords

  • Flow measurement
  • Precision agriculture
  • Spray card
  • Sprayers
  • Water-sensitive paper

ASJC Scopus subject areas

  • Forestry
  • Food Science
  • Biomedical Engineering
  • Agronomy and Crop Science
  • Soil Science

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