Vince Whitehead (2001)
This report gives details of the development and selection of a handpump suitable for use with domestic rainwater harvesting tanks in East Africa. The objective of the project was to develop a small low cost handpump, which can be manufactured, maintained and repaired with a minimum of tools and skill and that the materials can be found in most local hardware outlets and markets.
Four designs were proposed which were selected from a range of pump technologies for low head and low flow rates. From these, two were selected for their ease of manufacture, low skill level and expected reliability. The two handpumps ('Harold' and the 'Enhanced inertia') were subjected to a series of performance and durability tests. From these tests, both handpumps were found capable of lifting at least 15 litres per minute at 70 cycles per minute with acceptable hydraulic efficiencies. The actual lifting rate was significantly greater than the value given in the specification.
The durability tests showed very little evidence of wear in either handpump after 145 hours continuous running other than some potential splitting in the valve surfaces. An extended endurance test on the recommended handpump, the Enhanced inertia, resulted in it lifting around 300,000 litres and having an equivalent life of 8 years.
The handpumps were produced in Uganda for less than $10 for a 3.5m length, which was one of the main criteria in the specification. The pumps were successfully manufactured by a number of technicians in Uganda after a two-day training workshop and this illustrates that the design and technology is appropriate.