Evaluating kaolin clay as a potential substance for ISO sprayer cleaning system tests

Authors: ROMAN, CARLA - The Ohio State University; Jeon, Hongyoung; Zhu, Heping; OZKAN, ERDAL - The Ohio State University

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/5/2023
Publication Date: 6/20/2023
Citation: Roman, C., Jeon, H., Zhu, H., Ozkan, E. 2023. Evaluating kaolin clay as a potential substance for ISO sprayer cleaning system tests. Applied Engineering in Agriculture. 39(3):347-358. https://doi.org/10.13031/aea.15466.
DOI: https://doi.org/10.13031/aea.15466

Interpretive Summary: Meeting sprayer ISO cleanout standards is critical for US sprayer manufacturers to export their sprayer to overseas. However, ISO cleanout standards for sprayers are outdated and contain insufficient technical details to interpret their test results which limits US manufacturers to develop and evaluate their sprayers with ISO standards. Laboratory instruments, spectrophotometer and fluorometer, were identified and evaluated with testing materials to address such ambiguity in ISO standards and provide technical details on predicting sample concentrations. The study outcomes showed the laboratory spectrophotometer had sufficient performance to detect the materials and the linear regression model developed from its outcomes showed less than 5% of prediction errors to predict the sample concentrations for one of testing materials. This information will be useful to US agricultural equipment manufacturers to develop and evaluate their future sprayers to meet the ISO standard.

Technical Abstract: ASP® 602 (kaolin clay) was evaluated as an alternate material for performing ISO 22368-1 sprayer clean out test standard. Recommendations for sample homogenization, measurement temperature and sample sizes to address potential concerns or technical challenges in assaying ASP® 602 samples were provided under relevant conditions. Linear regression models for predicting ASP® 602 concentrations from 0 to 100 ppm (mg·L-1) in sample mixtures were developed using outputs from a spectrophotometer and two different turbidimeters. Test results showed that the three instruments could measure ASP® 602 concentrations as low as 2 ppm. Validations of the developed models showed approximation errors were 0.9% to 24.6% and 0.1% to 18.4% for the spectrophotometer and the turbidimeters, respectively. However, their maximum absolute errors were less than 3.7 ppm for the spectrophotometer and 2.3 ppm for the turbidimeters within the validation range. Two agitation and cleaning systems of a sprayer were evaluated with ASP® 602 following the ISO 22368-1 clean out procedure. Residue reduction factors from the initial mixture concentration were 163 for one system which did not meet ISO 16119-2 environmental requirement (factor over 400) and 819 for the other system which exceeded the requirement. Analysis results of ASP® 602 samples from ISO 22368-1 clean out tests showed that ASP® 602 could be used as a potential testing substance to evaluate and differentiate the performance of agitation and cleaning systems of sprayers.