Design, construction, and field testing of a spiral water wheel pump

Abstract

The global expansion in farmland and the increase in the world population has compounded the need for more efficient water use. The spiral water wheel pump can be a valuable and low-cost option for pumping water for surface and subsurface irrigation for farmland near flowing water bodies. This low-cost water-lifting device, which uses the kinetic energy of a flowing stream/river to lift water to homes and farmlands, can help smallholder farmers expand the growing season into the dry season. It is more cost-effective than conventional energy sources. It can be used in areas with limited access to electricity or fossil fuels because the energy of pumping is derived from the kinetic energy of flowing water. Its simplicity, adaptability, and low maintenance requirements make it a valuable tool for communities seeking water security and improved livelihoods. The main objective of this study was to develop performance curves for a version of the pump fabricated from polyvinyl chloride (PVC) and wood, materials that are readily accessible to smallholder farmers in Africa, to optimize its performance for different field conditions. Laboratory and field tests were performed in Illinois, United States of America, and Sierra Leone, West Africa, with pumps with several pipe diameters/pipe configurations and wheel diameters. During the laboratory tests, a 0.6m diameter single-layer pump with a 2.5cm pipe diameter (18 coils) lifted water to a maximum height of 3.4m. When a 3.8cm pipe diameter (10 coils) was used, the maximum height was reduced to 2.7m. Field tests at an experimental site in Fulton County, Illinois, generated a maximum height of 3.4m and 3.1m when 2.5cm pipe diameters were used on 1.22m and 0.6m diameter wheels, respectively. In Sierra Leone, the maximum height generated was 16m and 8.5m for the 1.22m and 0.6m diameter wheels, respectively, with a 1.9cm pipe diameter. In all the field tests, the pumps only worked when the water velocity exceeded 0.6 ms-1, smaller streams with a velocity less than 0.6 ms-1 can be channeled if necessary. These results indicate that this pump can improve dry season productivity for farmland near the flowing water bodies in developing countries like Sierra Leone. Key words: Wheel diameter, pipe diameters, pipe configuration, discharge rate, stream velocity