Dripper testing: application of statistical quality control for measurement system analysis/Ensaios de gotejadores: aplicacao de controle estatistico de qualidade na analise de sistema de medicao

Laboratory tests for technical evaluation or irrigation material testing involve the measurement of many variables, as well as monitoring and control of test conditions. This study, carried out in 2016, aimed at using statistical quality control techniques to evaluate results of dripper tests. Exponentially weighted moving average control charts were elaborated, besides capability indices for the measurement of the test pressure and water temperature; and study on repeatability and reproducibility (Gage RR) of flow measurement system using 10 replicates, in three work shifts (morning, afternoon and evening), with 25 emitters. Both the test pressure and water temperature remained stable, with "excellent" performance for the pressure adjustment process by integrative-derivative proportional controller. The variability between emitters was the component with highest contribution to the total variance of the flow measurements, with 96.77% of the total variance due to the variability between parts. The measurement system was classified as "acceptable" or "approved" by the Gage RR study; and non-random causes of significant variability were not identified in the routine of tests. Key words: dripper flow statistical process control repeatability and reproducibility control charts stability and capability for measurement process Os ensaios laboratoriais para avaliacao tecnica ou estudo de material de irrigacao envolvem a medicao de diversas grandezas, bem como o monitoramento e controle das condicoes de ensaio. A presente pesquisa, realizada em 2016, teve por objetivo utilizar tecnicas de controle estatistico de qualidade para avaliar resultados de ensaios de tubos gotejadores. Foram elaborados graficos de controle para media movel exponencialmente ponderada, alem de indices de capacidade para o processo de medicao da pressao de ensaio e temperatura da agua; e estudo de repetitividade e reprodutibilidade (Gage RR) para vazao, no qual foram utilizadas 10 repeticoes, sob tres turnos de trabalho (manha, tarde e noite), com 25 emissores. Tanto a pressao quanto a temperatura se mantiveram estaveis, com desempenho "excelente" para o ajuste da pressao via controlador proporcional integrativo-derivativo. A variabilidade entre emissores foi a componente de maior contribuicao na variancia total das medicoes de vazao, sendo 96,77% devida a variabilidade entre pecas. Classificou-se o sistema de medicao como "aceitavel" ou "aprovado" mediante o estudo Gage RR; e nao foram iden