Effects of high-frequency pressure pulse generated by a jet tee on the clogging of labyrinth emitter

Abstract: Emitter clogging is the key obstacle to the development of drip irrigation technology. For this reason, a jet tee was developed in this study. Taking three pressures (constant pressure, fluctuating pressure on the left and right sides of the jet tee.) and three turbid concentrations as factors, the experiment was carried out by using a complete combination of the test factors. A study of labyrinth emitter clogging was conducted to determine the effects of high-frequency pressure pulse generated by a jet tee versus constant pressure on the relative discharge of Drip irrigation emitters (Dra) and the coefficient of uniformity (CU). The results showed that the values of Dra and CU of the jet tee group were 10.8%-14.8% and 21.1%-44.9% higher than the ordinary tee group, respectively. At different muddy sediment concentrations (0.5, 1.0 and 1.5 g/L), for constant pressure groups, Dra decreased to 74% after the 16th, 11th and 7th irrigation run respectively and was considered as a severely blocked. However, for the left side of the jet tee, Dra was still higher than 75% after the 18th, 14th, and 11th run respectively. For the right side of the jet tee, Dra was still higher than 75% after the 16th, 13th, and 10th run respectively. It can be seen that high-frequency pressure pulse generated by a jet tee has stable anti-clogging performance. At the low (0.5 g/L) and the medium (1.0 g/L) concentrations of muddy water, the emitters did not easily clog. The Dra at the high muddy (1.5 g/L) sediment concentrations remained to decrease drastically. However, the Dra at the low muddy sediment concentrations remarkably decreased after the 12 th run. The Dra at the medium muddy sediment concentrations remarkably decreased after the 10th run. For pulse pressure group with high concentration, the Dra decreased to 76% after the 11th run. However, for pulse pressure group with the low and the medium concentration, the Dra was still above 92% after the 11th run. For pulse pressure group with the low and the medium concentration, the CU remained above 84% after the 12th run. However, for pulse pressure group with high concentration, the CU decreased below 80% after the 7th run. The Dra and CU of the high muddy sediment concentrations (1.5 g/L) differed significantly (P<0.01) from those of the low and medium muddy sediment concentrations (0.5 and 1.0 g/L). Under three muddy sediment concentrations, the possibility of clogging quickly increases at high muddy sediment concentrations (1.5 g/L). However, at this concentration, the jet tee was still more resistant to clogging than the ordinary tee. It is recommended that a jet tee be used in place of the ordinary tee in the drip irrigation system to prevent emitter clogging.