Service Contract No 2007 / 147-446 NYANYALI ... - Swaziland

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( d ) ………………………... (3)52d1Where: = length of the reducer (mm)d1 = smaller inner diameter (mm)d2 = larger inner diameter (mm)A 100-300 eccentric reducer is installed with the straight side towards the top, to prevent aircollecting in the pipe and an 80-200 concentric reducer on the delivery pipe (figure 7). Thelength of the eccentric reducer is 450mm and according to the above equation this should beat least 1000mm long. The concentric reducer is 150mm in radius, 450mm shorter than therecommended minimum calculated using equation 3 above. The unacceptable dimensions ofthe eccentric reducer affects pump performance substantially because it is directly attachedto the pump suction and the sudden restriction in size increases turbulence occurrences andcause irregular feeding of the pump hence cavitation.Figure 7. Incorrectly dimensioned eccentric reducerThe unacceptable dimensions of the concentric reducer had negligible effects on theperformance of the pump and the entire system.Nyanyali Farmers Cooperative Report - 2009 Page - 13 -
4.1.1.1.3 Suction Pipe InletsSpacing and placing of suction pipe inletsIn a well constructed sump the inlet of the suction pipe must be in accordance to therequirements of at least 0,5d (d = inner diameter of the suction pipe) from the bottom of thepump sump (figure 8) and at least 1,5d away from the side of the pump sump.1.5dd0.5dd3d 3d 1.5dFigure 8. Spacing and placing of suction pipe inletsThere is no proper intake structure instead the suction inlet (foot valve) is suspended at thebank of the Mkhondvo River (figures 9). The foot valve is not protected in any way and isintermittently in direct contact with the bottom of the channel and debris carried with the riverwater. This is not acceptable. Sand bangs are used to redirect the receding river water backinto the sump, especially when the river level drops. The sump has no provision for cleaning,in order to clean this sump one has to swim in the crocodile infested river.Figure 9. Nyanyali intake sump along the Mkhondvo RiverNyanyali Farmers Cooperative Report - 2009 Page - 14 -
Page 1: Restructuring and DiversificationMa
Page 5 and 6: 8 RECOMMENDATIONS .................
Page 7 and 8: ABBREVIATIONSAbbreviationAEARCASAEC
Page 9 and 10: 2 B A C K G R O U N D O N I R R I G
Page 11 and 12: 3 T E C H N I C A L A U D I T R E P
Page 13 and 14: 7,1 Type type Vyrsa 70 Vyrsa 707,2
Page 15 and 16: Soil informationSoil properties use
Page 17 and 18: 4 F I E L D E V A L U A T I O N O F
Page 19: Figure 5. 2 x 300mm x 45° bends on
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Page 25 and 26: Table 1. pump and motor specificati
Page 27 and 28: Figure 13. Inside Nyanyali pump hou
Page 29 and 30: pipe:Filters:Pumpingequipmentand el
Page 31 and 32: 4.1.3 S u p p l y S y s t e mThe ev
Page 33 and 34: When down -stream pressure falls be
Page 35 and 36: 5.1.1 S p r i n k l e r p r e s s u
Page 37 and 38: 6 A S S E S S M E N T O F O P E R A
Page 39 and 40: indication of the amount small grow
Page 41 and 42: 7 C O N S T R A I N T S T O E F F I
Page 43 and 44: ‣ The optimum sprinkler operating
Page 45 and 46: 8 R E C O M M E N D A T I O N STo e
Page 47 and 48: ‣ A consortium could be formed fo
Page 49 and 50: Accurate details are required also
Page 51 and 52: 12. Solomon K.H. 1988a, Irrigation
Page 53 and 54: Nyanyali Farmers Cooperative Report
Page 57 and 58: SEB usage for River pump station Ph

Service Contract No 2007 / 147-446 NYANYALI ... - Swaziland

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