Ensuring proper flow rates from each nozzle on an agricultural sprayer has become even more important as advances continue to be made in precision application technology. In this article, we describe the structure and testing of a sensor technology based on optical cross-correlation to determine the flow rate of individual sprayer nozzles. An advantage of this technology is that it does not require that impellers or other components be placed in the flow, which could cause plugging. The only moving part in the entire system is a solenoid used to inject a tracer dye. The objective of this study was to evaluate the ability of this sensor technology to determine volumetric flow rate from a single nozzle as used on an agricultural sprayer system. Tests were conducted at four system pressures (100, 200, 300, and 400 kPa) and with four nozzles in the 80° extended-range flat spray nozzle family to produce different flow rates (from 0.46 to 2.74 L min-1). Thirty-five samples were taken for each test condition. Five randomly selected samples were used to create a calibration curve for the sensor system, and the remaining 30 samples were used for validation of performance. The worst absolute error for flow rate estimation in percent was 7.9%, while the mean absolute error in percent was 1.6% for all measurements. While the flow rate estimates for the XRC8006 nozzle at 100 kPa exhibited bias in the errors, for the rest of the test conditions, the errors were clustered around zero. The overall mean absolute error of 1.6% indicates the capability of this sensor technology to monitor flow rate of individual nozzles. However, the bias in errors in one test condition demonstrate that more testing needs to be conducted with a variety of different nozzle types and sprayer configurations before this sensor technology can be considered applicable for all sprayer applications.
Digital Object Identifier (DOI)
Dvorak, Joseph S. and Bryant, Luke E., "An Optical Sprayer Nozzle Flow Rate Sensor" (2015). Biosystems and Agricultural Engineering Faculty Publications. 46.