Service Contract No 2007 / 147-446 NYANYALI ... - Swaziland
Service Contract No 2007 / 147-446 NYANYALI ... - Swaziland
Service Contract No 2007 / 147-446 NYANYALI ... - Swaziland
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Figure 11. Atmospheric pressure vs. height above sea levelThe suction height was measured to be approximately 4.5 meters. The NPSH required(NPSHr) of the ETA 80-250 end suction pump is 4.3m (from attached pump curve). From theabove formula the maximum allowable suction height is therefore 4.55m and this calculationconfirms that river pumps are installed with a correct suction static height.Further analysis compared NPSH available (NPSHa) to NPSH required. The NPSHrequirements of 4.3 meters are well within the available NPSH of 4.55 meters. A safety factorof 0.5 is factored in this calculation as per manufacture’s requirement. This conforms to therecommendation of NPSHr < NPSHa (ARC, <strong>2007</strong>) required for optimum pump performance.The difference between these two figures is too small and might be affecting pumpperformance.4.1.1.2 Pump evaluationThe essence of evaluating this pump was to determine whether the pump function asindicated by the pump curve and to ascertain, if any, design, installation and managementfaults. The performance curve of the installed pump is attached under ‘product information’below and table 1 below indicates Nyanyali Farmers irrigation pump and motor specificationsas observed from the information plate.Nyanyali Farmers Cooperative Report - 2009 Page - 17 -