Windmill Lakerpolder - Windmills on Waymarking.com

The Bosman mill is a small polder mill designed and constructed in 1929 by Bas Bosman in the Dutch town Piershil. It is applied anywhere in the world.

In early models of this windmills, the bevel gear was made from the differential of a T-Ford. The mill worked semi-automatic. It turned automatically on the wind through the tail blade and vane, but had to be turned from the wind by turning the vane by hand a quarter, until it laid flat and caught no wind any more.
Later the operation was controlled by the water level in the ditch (by a floater) and a support vane, at right angles to the main vane.
Later models worked with a differential from the A-Ford (until 1960) and the Ford V8 (until 1977). From 1977 Bosman makes the drives by themselves.

In 2006, the latest model came in the market. This includes many improvements.
This mill is fully automatic. There’s a floater on the water to set, connected by a rod, the position of both vanes. If the water level in the ditch is high, the main vane is vertical and the auxiliary vane lies flat. This turns the mill by itself in the wind. When the water level drops, the floater adjusts the vanes until the lowest position of the main vane is flat and the auxiliary vane is vertical. This turns the mill from the wind.

The spinning wings drive a centrifugal pump, the water will be pumped from the ditch. If the water is sufficiently lowered, the floater turnes the vanes in such a way that the blades rotate out of the wind and the drainage stops. The pump provides enough resistance to storm to avoid overrunning of the mill. The greatest danger is dirt that is sucked into the pump or blockage of the floater movement. Therefore there are always dirt grills in the ditch, just before the mill.

The mill is mainly used for the pumping of large amounts of water with only a small discharge head. The starting wind speed is about 3 m/s at a discharge head of about 0.3 meters. The mill is suitable for drainage of an area of 20-25 ha in flat, open polders.

Head - Wind - Capacity
0.5 m - 4 m/s - 0.7 m³/min
0.5 m - 7 m/s - 1.8 m³/min

Except for the drainage of an area the mill may also be applied for circulating water and irrigation of nature reserves. It is an environmentally friendly way, because no electricity is used. Moreover, the wind is for free.

Date of Manufacture: 01/01/1652 Purpose: Water Pumping Open to the public: yes Is This Windmill Functional?: Yes! Windmill Farm: no Museum on Site: no Cost: Not Listed

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Date Logged Log User Rating   10/12/2023 Andre 61 visited it 11/07/2014 McGhostburg visited it

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