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

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Nyanyali Farmers Cooperative Report - 2009 Page - 9 -
4 F I E L D E V A L U A T I O N O F I R R I G A T I O NS Y S T E M4.1.1 P u m p s A n d P u m p S t a t i o n s4.1.1.1 Pump Suction SideThe majority of problems occurring with pumps are usually the result of poor suction sidedesign and installation. The installation and design of the suction side must ensure thatturbulence occurring in the suction pipe and collection of air in high places in the suction pipe,is prevented. In view of the above, the different suction side components were evaluated.4.1.1.1.1 Suction Pipe Flow RateThe suction pipe flow velocity of river and booster pumps was calculated as follows:353,68 QV m / s2d……………………….… (1)Where: V = flow velocity in pipe (m/s)Q = flow rate (m³/h)d = inner diameter of suction pipe (mm).One ETA 80-250 pump is installed and the duty point inscribed on its information plate is148m³/hr flow at 80m head. pump discharge was ascertained by getting the multiply of thetotal irrigated area under cane (43 ha), industry norms of 2.57 sprinklers per hectare, 1.4m³/hrsprinkler discharge and 10% safety factor for pump discharge. The pump must, thereforegenerate at least 170.2 m³/hr of flow to meet irrigation requirements.Based on equation one above the flow velocity at the estimated pump flow through the300mm suction manifold is 0.67 m/s. According to the Agricultural Research Council, ARC(<strong>2007</strong>) the ideal suction pipe flow velocity must be 1.0 m/s, but suction pipe flow velocities upto 1.5 m/s are acceptable. A flow velocity through the suction manifold is within therecommended limits.Nyanyali Farmers Cooperative Report - 2009 Page - 10 -
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: Soil informationSoil properties use
Page 19 and 20: Figure 5. 2 x 300mm x 45° bends on
Page 21 and 22: 4.1.1.1.3 Suction Pipe InletsSpacin
Page 23 and 24: hf6375kQ4d2……………………
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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