Possible improvements to the existing pumps
Ideas on how to improve the Abakus pumpProblem: the rope falls off the bicycle wheel.
Possible Solutions: - Use a different wheel, e.g. a motorcycle wheel. They are wider and have larger rims, so it would be more difficult for the rope to jump off the mechanism, however it is an expensive solution. Also, motorcycles or bikes are very rare in rural Africa and therefore they are considered a luxury and hence it is doubtful that the owner would be willing to sacrifice his prized possession to build a pump. - Widen the bicycle wheel - Improve the guide rail using wooden brackets (Figure 13) or an old bicycle tyre cut in half. The halved tyre would also protect the wheel frame from the water dripping from the rope which would reduce the corrosion of the wheel Problem: the rope that is used is of bad quality and has a tendency to stretch. This releases the tension in the rope and causes the rope to slip on the wheel. Possible Solutions: - Create the tension in the rope by having a freestanding weight taking the slack in the rope. This would require the rising pipe to be allowed to move up and down with the weight (i.e. have a vertical degree of freedom) (Figure 14). - Add a grappling mechanism to the wheel Problem: the rope has a tendency to break often due to wear Possible Solutions: - Add a wheel in the guide box to reduce the friction on the rope (Figure 14). - Consider using a different rope (e.g. make ropes from weeds?) Other possible improvements: - Communities are capable of melting plastic and casting it in sand moulds. This could be used to make plastic discs to reinforce leather washers (Figure 15). This could allow the pump to be used in deeper wells. Ideas on how to improve Nafe pumpNafe pump is a new system, so not much is known yet about the problems associated with the design. The most complex parts of the pump are the plunger and foot valve. They appear to be manufactured outside the community. It might be possible to use ball valves as shown in Figure 16.
|