A wind pump is a wind mill that pumps water from a variety of water sources, including boreholes. The pumped water is usually used to provide clean drinking water, irrigate farmland, or hydrate and feed livestock. Wind pumps are also used to alleviate flooded areas from excess water and for producing salt from sea water. Often used in rural, arid and semi-arid areas, wind pumps can be seen in parts of Argentina, South Africa, Asia, and the United States.
The origin of the wind pump dates back to the late nineteenth century. They were an important part of the economic development of many remote areas in the United States. Advances in the technology continue to be made.
The main types of windmill pump are piston, centrifugal, and mono pumps. In general, however, windmill pumps can be classified into two types: the horizontal axis wind pump, which is more commonly used, and the vertical axis wind pump. As the names suggest, the rotor shaft in the horizontal axis wind pump runs parallel to the ground, whereas in vertical axis pump, it runs perpendicular to the ground. The types of rotors used in horizontal axis wind pumps are usually multi-bladed or three-bladed aerofoil. The common rotor types of vertical axis windmill pumps are Panemone and Darrieus.
The rotor shaft of the horizontal axis wind pump must point towards the direction of wind, and the generator must be installed at the top of the tower. On the other hand, a vertical axis wind pump does not require its vertical rotor shaft to be positioned into the wind and the rotor can be installed near the ground. Although the cost of maintenance of horizontal axis wind pumps is high, their efficiency is typically greater than that of vertical axis wind pumps. Wind pumps have a tail vane that automatically turns the machine away from the direction of flow of wind, thereby avoiding damage due to high wind speeds.
In general, piston pumps are used for pumping water from a borehole. The pump and rotor should work together to efficiently operate the wind pump. The flow of wind facilitates the rotation of the rotor blades and the power is transferred to the pump rods, which are usually made of galvanized steel. This causes the piston pump to pump water to a storage tank, which can later be distributed.