Hydraulic Performance of Automatic Flushing Valve at the End of Dripline

Abstract

【Background and objective】 Emitter clogging is a problem facing drip irrigation and drip-line flushing is an effective anti-clogging technology. The aim of this paper is to study how key structural parameters of automatic flushing valve at the end of drip-line impact its hydraulic performance as well as the underlying mechanisms. 【Method】 Three structural parameters were examined: dentition length (L) and width (W), as well as the height of the bonnet (Z) in the valve. Overall, there were seven flushing valves with different structural parameters, which were made by a 3D printer. For each valve we tested how its hydraulic performance changed with the applied water pressure (H2), flushing time (T), flushing volumetric rate (Q) and flushing velocity (V). 【Result】 When H2 was in 0.038~0.096 MPa, T varied from 7.5 to 32.1 s, Q from 2 220 to 5 725 mL, and V from 0.87 to 1.53 m/s, depending on the valves. When H2≤0.058 MPa, T and Q were negatively correlated with H2, while when H2>0.058 MPa, H2 only negatively affected T and did not result in a noticeable change to Q. Both T and Q were positively correlated with L, W and Z; the minimum flow area in the labyrinth channel depended on L and W. The amount of water entering the upper cavity of the valve was affected by Z, and as a result, it impacted T and Q as well. The impact of the three structural parameters on T and Q was ranked in the order of W>L>Z. V was affected by H2 more than by the structural parameters. 【Conclusion】 T and Q are closely related to the velocity, the amount of water flowing into the upper cavity, and the distance between the elastomer and the water outlet. The air in the upper cavity within the valve is a key factor impacting on T and Q; V is affected predominantly by H2.

Keywords

• drip irrigation
• anti-clogging
• flushing time
• flushing water volume
• flushing velocity