27 – HAND PUMPS
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Publisher Summary
This chapter discusses the development and technologies of hand pumps. For shallow well pumps, several cheaper designs are under way. The Blair PVC-VLOM, developed in Zimbabwe, has no lever and no leather seal. It uses standard PVC water pipes and fittings and non-return ball-type valves. It is easy to make and operate, and requires little maintenance. The pump cylinder, a 5 cm diameter PVC pipe, is inclined at 30 degrees from horizontal, enabling the operator to pull and push directly on the piston rod. Other pumping mechanisms under development include the Mono and Moyno pump that features a spiral stainless steel rotor in rubber housing and the hydropump Vergnet, a pedal operated pump using hydraulic action on an inflatable silicon rubber bag inside the pump cylinder. The pump stand is made of mild steel that is not as brittle as cast iron. It can be easily taken apart for maintenance and has three legs for stability. The spout is angled to prevent the introduction of stones. The entrance of the handle is designed to prevent fingers being mauled. The handle is of square cross-cut steel so as to prevent breaking or snapping.