Wind rope pumps, continued

The wind rope pump makes the labour-intensive hand pumping superfluous, which for irrigation purposes, requiring many pumping hours, is a substantial step forward. The wind rope pump is a light weight wind pump in which a number of novel design features- developed at universities by the former CWD- organisation[1] have been incorporated in the design. It drives a rope pump instead of a classical piston pump.

With a cost of around 700 Euro this product is 5-10 times cheaper than comparable  conventional wind pumps and more sustainable because of the simple design and local availability of spares.

In Nicaragua, some 50% are in use for livestock watering, sometimes combined with irrigation, the others for small-scale irrigation together with domestic water supply.

The Nicaraguan rope and washer wind pump or "Aerobomba de Mecate" can be classified as a second-generation, low-cost wind pump. The existing models in Nicaragua indeed are rather “simple” structures compared to conventional wind pump designs. They have a steel rotor and tower and operate a rope pump comparable to the hand rope pump described in the previous section. The transmission between the rotor shaft and the rope pump consists of two pulleys and a rope. If there is no wind, the pump can be operated by hand.

Locally available, standard materials are used for the construction; assembly can be done by a workshop without the need for sophisticated tools.

Qualifications of the Nicaraguan wind rope pump are: low investment cost; easy maintenance, which is done by the user; application of a simple but proven pump type; the use of basic tools and materials available on the local market.

 

  h8

The standard type rope wind pump produced by AMEC is officially known as the H-270 and is the model shown in the figure. The number "270" refers to the maximum freedom of the rotor head to orientate itself into the wind (which is 135° in both directions). If the wind comes from the back, the rope is pushed against the tower and runs off the pulley. This makes the type more appropriate for regions with "unidirectional" winds (coming mainly from one direction) as is the case in the Chimoio region in Mozambique, where the wind direction is predominantly southeast during most of the year.

 The H-270 exists in three different models with a rotor diameter of 8, 10 and 12 feet and different tower heights.

The H-270-8 as introduced in Mozambique is a model with an 8' rotor (2.40 m) on top of a 6-meter tower. The maximum pumping depth, as recommended, is 20 m. The output at 10 m head is 25 l/min at a wind speed of 5 m/sec, based upon the documentation provided by the manufacturer. The costs of the H-270-8 are between US$ 800-1000, ex workshop Chimoio.



[1] CWD was a Dutch organisation that developed and transferred the technology of wind pumps to developing countries. It was closed in 1990, but many CWD-innovations have been introduced in wind pumps worldwide.