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More on the Why and the How of the Demotech RopePump

Why

• Industrial (donated) hand pumps for communal wells often break down after two years. If cost for maintenance is born by the users, development projects may donate a robust industrial pump such as the Indian Mark II. In practice this cost is too high when repairs prove necessary.
• An alternative reliable hand pump is also needed for private use and to irrigate gardens. Next to communal pumps, pumps on private wells could raise the standard of living if they were low in cost, reliable and lift water effectively. To irrigate a garden in the dry season to increase income can only be realized if such a hand pump converts human energy with little loss in water lifted.
• Local affordability and local maintenance is a must, together with an excellent pump performance. Local affordability asks for a cost reduction compared to imported industrial goods in a twenty to hundred fold way. Local maintenance is only possible when local craft or the future user can have constructed the pump.
• A pumping system should allow full closure of a well against contamination of drinking water. This specially regards pumps on communal wells. Industrial pumps need to be bolted on to a concrete slap, positioned over the well. But this makes the water in the well inaccessible in case of break down of the pump. A solution is immediate maintenance being available or access to the well through an emergency hatch.

• Low cost modern materials as plastic pipe and rope are used in a rotating hand pump system. In the working principle of the chain pump the chain is replaced by rope and the rotating chain drum by a specially constructed rubber disk wheel. Such a rubber wheel can be made from used car tires. Other additional needed materials can be found at little or no cost.
• Little time is needed to instruct users or craftsman to construct a rope pump. People adapt the basic principle to their own needs, be it shallow or deep wells and bore holes, or horizontal pumping from a pond. To achieve quality, instruction should center on making understood the relation between wheel diameter and the diameter of the plastic pump pipe. Crucial is the correct construction of the place where the rope movement changes direction from downwards to upwards in the bottom of the well.
• If instructions regarding quality are followed, the water water gift of the rope pump outclasses the traditional pump by far. The Demotech Ropepump is superior by far in all aspects of use, as well as price per unit, when compared to other types of hand-pumps. Further development could mean cutting the cost-price per unit in half, making it suitable for 100m-holes, quick and efficient maintenance, robust construction and housing, as well as more-efficient propulsion and higher efficiency.
• The rope pump can be adapted to a special situation. To make it suitable for being mounted on a well cover the bearing of the pump axle is positioned at one side of the pump wheel only. In most other set-ups it is preferred to have the bearing on both sides of the pump wheel, better even: at both the very ends of the axle and handle.
• Re-designed water pump based on continuous pumping action, rotational as well as linear, thus avoiding peak loads and creating a condition that fits engineering capacities to be realized in local crafts.
• Selection of technology for pumping water that is immediate understood by just looking at it. Thus creating the intellectual capacity for upkeep and repair.
• Cost of construction within local limits for investment, risk is reduced to locally acceptable limits
• Functional quality is high, pumping action is robust accepts rough workmanship , water gift is high, also from wells beyond 50 meters depth, efficiency is high in normal conditions, demands for hygiene can be answered.
• There is constructional flexibility: the RopePump can be build in many ways, for many different purposes and from different materials as available. Experimentation is easily done and helps people get able to get the most out of what is available.