PROGRAM OF PUMP DEVELOPMENT AT MOROGORO
Work was started by Professor Rana of the Agric Engineering Department in 1972. He adapted a commercial "Stuart Turner: single cylinder double acting piston pump to one-man pedal drive utilising a bicycle frame, bicycle chain and sprocket drive and a cement flywheel.
Msimbira (1974) made performance tests and at the request of Howard Hepworth, the pump was used at Ulaya Ujamaa Village for several months. Ryoba (1974) reported that the pump was effective.
However the output from the pump – 0.25 litre per second – was fairly low, and the cost of the pump alone was around US$ 150-00 in 1976 prices. For the pumping heads which we expected (typically 3 metres) then the water delivery per man-hour and the energy requirement in Watts were really too low, and a means of increasing output was sought.
It was realised that running piston pumps above their design speed results in severe efficiency losses in the valves; and it was found that larger commercial piston pumps were very expensive.
In 1976 the write produced a 4-man pedal centrifugal pump, using a commercial "Stuart Turner Model 26" pump driven at 3,500 rpm through a 2-stage chain and then belt drive. Flow was around 2 litre/second through 4 metres total head, with an efficiency of approximately 25% and a human power input requirement of approximately 80 watts for each of the 4 riders. Pump cost was US$ 150 (1976 prices) and the cost of the completed machine was US$ 400-00 (1976 prices) including labor, overheads and margins. It was sold to UNICEF for their Nairobi Village Technology Center and merited a photograph in Time Magazine. At that point in time I discontinued work on centrifugal conversions because of relatively low pump efficiency.
Kimboka (1977) designed, constructed and tested a man-powered tyre-diaphragm pump with a lever action. This pump was found to be 70% efficient when operated at 10 strokes per minute with zero suction head. Maximum suction head was 1.5 metres and efficiency fell rapidly with increasing suction head and increasing speed of operation.
Weir in 1977 developed a 2-man pedal piston pump, whose stroke could be adjusted by varying the throw of the crank, thus creating flexibility for different heads and operator fitness levels. Output was 1.5 litre/second at maximum stroke, and efficiency was about 60%. Estimated capital cost US$ 375 (1976 prices). The pump was demonstrated at the Rural Technology Meet at Arusha., Tanzania, September 1977. Because of the weight and size of the pump it was decided to simplify the drive mechanism. The resultant system is described in this report and a second machine of this type was sold to UNICEF for use on a Women’s Project in Mali West Africa.
PUMP CONSTRUCTION.....................................................................Pump090.htm
PUMP DRIVE MECHANISM..............................................................Pump100.htm
PUMP PERFORMANCE......................................................................Pump110.htm
DRIVE MECHANISM COMPARISON..............................................Pump120.htm
PRODUCTION COSTS........................................................................Pump130.htm
OPERATIONAL COSTINGS...............................................................Pump140.htm
SUMMARY AND CONCLUSIONS....................................................Pump150.htm
REFERENCES......................................................................................Pump160.htm
APPENDIX........................................................................................... Pump170.htm
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