The Effects of Dripline Layout on Performance of Automatic Flushing Valve

Abstract

【Objective】 The functions of drip-irrigation systems depend on many factors and in this paper, we investigated the performance of the automatic flushing valve as impacted by layout of dripline. 【Method】 The experiment compared four flushing valves which were manufactured by 3D printing. They were then fixed at the end of the 0.5 m Φ16PE pipe (C1), a 48 m dripline (C2), and two 48 m long driplines connected in parallel (C3), respectively. The changes in flushing duration (FD), flushing water volume (FQ), flushing velocity (FV) and the minimum inlet pressure of the driplines required for the flushing valve automatic closing (H1min) under different layouts were measured and compared. 【Result】 The flushing velocity of the single dripline in C2 and C3 decreased from 0.82~1.03 m/s to 0.34~0.66 m/s, and the difference between the dripline inlet pressure H1 and flushing valve inlet pressure H2 was in the range of 0.114~0.132 MPa and 0.047~0.088 MPa, respectively. Compared with C2, C1 and C3 reduced H1min by 74.8% and 40.4% on average, respectively. When FD or FQ was the same, H1 required for the four flushing valves varied in the order of C2 > C3 > C1. When H2 0.05 MPa, FD decreased slowly by 164.7 s/MPa on average. Regardless of the dripline layouts, FD and FQ are quadratic functions of H2. 【Conclusion】 The FD and FQ are related to H2, and independent of the dripline layouts. When H2 > 0.05 MPa, FD changes steadily and the flushing effect is uniform. Fixing the flushing valve at the end of multiple driplines in parallel reduces the system pressure for automatic closing of the flushing valve. However, further work is needed to test if the flushing performance meets the requirements in the field.

Keywords

• drip irrigation
• automatic flushing valve
• flushing duration
• flushing water volume
• flushing velocity