Development of a filtration system with high-frequency flow reversal/Desenvolvimento de um sistema de filtragem com reversao de fluxo de alta frequencia

The aim of this study was to develop a filtration system with high-frequency flow reversal and minimum requirement of water for cleaning routines. The system was developed in the period from 2011 to 2013 and consists of three screen filters and eleven solenoid valves electronically controlled by a controller that operates based on head loss measurements. The following evaluations were carried out: head loss curve as a function of flow rate; filtrating efficiency as a function of solids concentration, frequency of flow reversal and increment in head loss. The experimental design was completely randomized in a factorial scheme with three replicates and two treatment levels for each factor. The filtration efficiency was equal to 98.6% for particles larger than 50 µm. The minimum volume of water for each cleaning of the filters was 5.39 L. The head loss increment in the filtration system with flow reversal at frequencies of 11.11 and 22.22 mHz was smaller compared with the filtration system without flow reversal. The developed filtration system has potential for filtering low-quality irrigation water, but requires periodic maintenance to clean the filter element. Key words: water quality emitter clogging screen filter Este trabalho objetivou desenvolver um sistema de filtragem com inversao automatica de fluxo de alta frequencia e consumo minimo de agua de limpeza. O sistema foi desenvolvido no periodo de 2011 a 2013 e e composto de tres filtros de tela e onze valvulas solenoides, acionadas eletronicamente por controlador baseado na perda de carga. Avaliou-se a curva de perda de carga em funcao da vazao e a eficiencia de filtragem em funcao da concentracao de solidos, frequencia de inversao de fluxo e incremento da perda de carga. O delineamento experimental foi inteiramente aleatorizado em esquema fatorial com tres repeticoes e dois niveis de tratamento para cada fator. A eficiencia de filtragem para solidos maiores que 50 pm foi de 98,6%. O volume minimo de agua para cada limpeza dos filtros foi de 5,39 L. A inversao de fluxo com frequencias de 11,11 e 22,22 mHz reduziu a taxa de crescimento da perda de carga comparado ao sistema funcionando sem inversao de fluxo. O sistema de filtragem apresentou potencial para filtragem da agua de baixa qualidade para irrigacao porem necessita de manutencoes periodicas para limpeza do elemento filtrante. Palavras-chave: qualidade da agua obstrucao de emissores filtro de tela