Design and testing of a front filter for the self-cleaning pump based on Archimedean spiral turbine

A filter before the pump is one of the most important components in the head of the drip irrigation system. The filter before the pump can be used to preliminarily filter the irrigation water, and then reduce the damage to the pump and the working pressure of the filter system after the pump, finally extending the working duration of the filter system for stable and efficient operation of the drip irrigation system. However, most self-cleaning devices that are driven by motors cannot be interrupted in the filtration process when performing self-cleaning work, leading to the consumption of electric energy. The purpose of this study is to solve the frequent interruption of the filter system for the better self-cleaning performance of the filter before the pump. The Archimedes spiral turbine was applied to combine the hydraulic drive and self-cleaning in the self-cleaning process of the filter before the pump. A systematic investigation was made to explore the influence of blade stride, blade angle, and blade numbers on the rotation speed of Archimedes spiral turbine. A test platform was developed to evaluate the speed of Archimedes spiral turbine when the flow rate was 50-150 m³/h (flow gradient was 25 m³/h). At the same time, a series of simulation tests were carried out on the Archimedes spiral turbine with different parameters by computational fluid dynamics software. The experimental results show that the rotation speed of Archimedes spiral turbine gradually decreased with the increase of the blade stride (or the decrease of the number of single-blade helices), where the reduction amplitude gradually increased. There was a relatively small increase in the rotation speed of Archimedes spiral turbine, with the increase of blade angle and number of blades, whereas, the amplitude continuously decreased. The linear regression showed that the influencing level on the rotation speed was ranked in the descending order of the blade stride, blade angle and blade number. TOPSIS comprehensive evaluation showed that the optimal combination of structural parameters was obtained as follows: blade stride 133 mm, blade angle 90°, and the number of blades 1. The optimal scheme was then introduced into the hydraulic-driven self-cleaning filter before the pump in the self-cleaning test. It was found that the flow rate of the self-cleaning test group was stabilized in the range of 294.9-296.6 m³/h after the initial flow reduction, while the flow reduction was only 1.13%-1.70% when the flow rate was 300 m3/h and the sediment content was 0.9 g/L within 12 h. Better filter cleaning was achieved in the self-cleaning device of a hydraulic-driven Archimedes spiral turbine. The finding can provide a strong reference for the design and optimization of the hydraulic-driven self-cleaning filter before the pump.