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Rope And Washer Pump The rope and washer pump is the most economical and simple form of water lifting service, ideally suited for rural applications...........Read More  Read more
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Rope And Washer Pump

The rope and washer pump is the most economical and simple form of water lifting service, ideally suited for rural applications. The pump can be manufactured using locally available materials with little building; hence costs of acquiring and maintenance would be low

In many parts of Zimbabwe, the water table is too deep to access with a treadle pump. For small-plot farmers living in these areas, drinking water is usually obtained by pulling up a bucket from a deep hand-dug well, an exhausting and time-consuming task. Irrigation remains out of reach. Rope and washer pumps are a simple and affordable technology that can meet the needs of small-plot farmers facing water challenges. The pump is designed to lift water from a depth of up to 40 meters for drinking water purposes, and up to 18 meters for irrigation purposes. (This discrepancy is due to the effort involved in lifting the large volume of water needed for irrigation.) With access to a rope and washer pump, a small-plot farmer can tap into ground water deep below the surface to irrigate fruits, vegetables, and other high value crops. The sale of these crops generates increased income and for many is the first step out of poverty.

Technical Description   
The rope-washer pump consists of a rope with knots or rubber washers, whose diameters are slightly less than the diameter of the pipe, placed at intervals along it. This assembly is drawn up inside a rising pipe, and is capable of drawing relatively large volumes of water to the height of the pump. During operation, the pipe is inserted into water and the rope drawn upwards through the pipe by means of a winding drum with a crank. Water is also drawn up and discharged at the top. The rope and washers pass round the winding wheel and return to the bottom of the pipe thus completing the circuit. This design can be modified to avoid slippage of the rope on the pulley by using old tyre casings to make the pulley wheel. To prevent the washers getting caught, and to support the bottom of the pipe above the bottom of the well or river bed, a suitable pipe stand and rope guide is necessary. Friction should be kept low by allowing leakage between the washers and the pipe stem

Extent of Use
The rope-washer pump is receiving moderate use in Kenya, Zimbabwe and Burkina Faso.

Operation and Maintenance
Rope-washer pumps rely are manufactured locally, and, therefore, are amenable to local repair and maintenance using simple, locally-available materials.

Level of Involvement
The components of this technology are community-manufactured and operated. Government and NGOs are often involved in the promotion of this technology and development of refinements.

Costs
Rope-washer pumps cost between $30 to $50 to construct. The construction cost increases in proportion with the lift required.

Effectiveness of the Technology
This technology is appropriate for all domestic uses and micro-irrigation or garden irrigation uses. This pump can pump high volumes with a low lift.

Suitability
The technology is suitable for abstraction from shallow wells of up to 10 m depth or from rivers and streams. It is easily adaptable to changing volumes by adapting the diameter of the pipe and washers.

Environmental Benefits
The introduction of a simple device such as the rope washer pump, lends itself to micro-scale gardening and the accompanying positive environmental management practices.

Advantages
The pump has no valves and does not require complicated bearings. It is easy to manufacture, with local resources, and is ideal for flood irrigation of small gardens.

Disadvantages
The pump has limited lift and poor pumping efficiency, as water is allowed to leak through the valves.

Cultural Acceptability
There are no known cultural inhibitions.

Further Development of the Technology
The rope-washer pump technology needs to be further disseminated to gain additional field experience of its operation. The efficiency of the pump needs to be improved.