Design for low cost and high reliability:-The Poldaw Windpump has a very simple but elegant design. Most successful small windpumps with a deep well capability use a speed reduction gearbox. However, gearboxes are expensive, difficult to manufacture, and require good lubrication and therefore high maintenance. The Poldaw transmission uses a simple crank and rocker arrangement, with a specially developed rotor which develops high torque at low speed. The elimination of the gearbox reduces the cost and improves reliability. Furthermore, the direct drive system permits complete counterbalancing of the pump rods weight, which enables the machine to pump more water in light winds when conventional machines stand still.
Lubrication only once a year: For the continuously moving joints, self-aligning ball bearing units are used, which are universally available, very reliable and only require greasing once a year. Other bearings and pivots which only move intermittently, are made from polymeric materials or hardwood.
Pumps and pipelines: The pump consists of a single-acting cylinder. The cylinder diameter is selected to suit the required pumping head. For pumping a long distance to a remote tank, an air chamber may be incorporated. This smooths out the pump pulsations and reduces the stresses on the mechanism.
Automatic Storm Protection: Poldaw Windpumps protect themselves from damage in very strong winds, by turning the rotor edge-on to the wind. This takes place automatically in wind speeds of over 50 km/h, and enables the windpump to withstand storms of up to 180 km/h (50 m/s). When the wind drops again the rotor resumes its normal position facing the wind.
The output capacities for the range of possible Poldaw Windpump applications can be seen in the following tables:
Poldaw 5.0m Windpump (Approximate outputs in litres per 24 hours):
|Total Pumping Head||Light Wind – 3 m/s||Medium Wind -4 m/s|
* Note – to achieve these outputs on heads of 75m+, spring counterbalancing is required.
Poldaw 3.5m Windpump (Approximate outputs in litres per 24 hours):
|Total Pumping Head||Light Wind – 3 m/s||Medium Wind– 4 m/s|