Impact of Elastic Diaphragm Hardness and Structural Parameters on the Hydraulic Performance of Automatic Flushing Valve

Abstract

Automatic flushing valve (AFV) can improve the anti-clogging ability of the drip fertigation system. The minimum inlet pressure (Hamin) required for automatic closing and the maximum flushing duration (FDmax) are two important performance indexes of AFV. The existing AFV products have the problem of larger Hamin and smaller FDmax, which result higher investment and operating cost, and poor flushing efficiency. Based on the mechanical analysis of the AFV elastic diaphragm and the derivation of the FD, elastic diaphragm hardness (E), ascending channel offset distance (D), and drain hole width (W) were selected as the experimental factors, and nine AFVs were designed by L9(33) orthogonal test method to investigate the influence of elastic diaphragm hardness and structural parameters on the hydraulic performance of AFVs. The hydraulic performance test results showed that the Hamin of the nine AFVs ranged from 0.026 to 0.082 MPa and FDmax ranged from 36.3 to 95.7 s. Hamin was positively correlated with E and D and negatively correlated with W. FDmax was negatively correlated with E and W and tended to increase and then decrease with D. All elastic diaphragm hardness and structural parameters had a significant effect on Hamin, and E and W had a significant effect on FDmax. Based on the range analysis, two new combinations of AFV elastic diaphragm hardness and structural parameters with minimum Hamin (E = 40 HA, D = 0 mm, W = 2 mm) and maximum FDmax (E = 40 HA, D = 2 mm, W = 1.68 mm) were determined, and the corresponding Hamin was 0.022 MPa, 63.3% lower than that of the existing product, and FDmax was 116.4 s, 71.2% higher than that of the existing product. In this study, two ternary nonlinear mathematical regression models of Hamin and FDmax with elastic diaphragm hardness and structural parameters was constructed. The simulation accuracy of the models is good and can be used to quickly predict the optimal combination of AFV parameters to satisfy the actual engineering-required Hamin and FDmax.