Windmill water pumps, which is actually an incorrect term for them – A “windmill” is something that harnesses the power of the wind to drive a grain mill. Years ago people used a wind powered water pump for pond, but nowadays they are mostly used for land drainage.
The correct term is a “windpump”. although we tend to get call anything which has blades and is turned by the wind a “windmill”. Another example is the giant electric-producing wind turbines that are still referred to as “windmills”!
Windmills have been around for a very long time, they first appeared in Persia in the 9th century AD and were later independently invented in Europe. Windpumps are a great invention – they can be used to move water to aid land drainage – which can be seen in many areas of Holland and other low-lying flatland areas and coastal regions such as the Norfolk Broads in the UK.
They can also be used to extract water from areas where there usually is no water readily available. Many western movies feature a windpump wheel creaking in the background before some boy gets a hole in his coat! The windpumps in these areas are used to extract water from a deep well to serve the local community or transport links.
What’s the difference between a windmill and a windpump?
The blade or sail design of a windpump differs greatly from that of a modern-day wind turbine. The blades on a windpump are much closer spaced and higher in number compared to a wind turbine.
Usually, the windpump has maybe 20 blades closely spaced and shorter in length – the wind turbine has around three blades equally spaced and longer.
The reason the windpump has so many sails closely spaced is so that they turn slowly with higher torque in low wind.
The back of the windpump has a tail that turns the sails into the wind and is also fitted with a safety feature which is connected to the gearbox fitted on top. When the wind speed gets too fast the tail automatically turns the sails away from the wind – this protects the gearbox from turning too fast and damaging the pump below.
How does a windpump work?
The windpump works by converting the turning action of the sails into a vertical up-down motion. this takes place via a gearbox mounted up at the top of the windpump.
The vertical shaft is connected to the pump section at the bottom which consists of a rubber diaphragm sandwiched between two cylinders. The rubber diaphragm has a hole in the middle of it with a lid that raises when the diaphragm goes down and closes when the diaphragm goes up.
This action pulls the water up through the hole, closes the lid, goes down, pulls up more water, and displaces the last lift of water out to the side away to another outlet. You can see it in action in the video I took.
Wind powered water pump for pond
The windpump I have shown you is a replacement for the one which originally existed on this farm but got into disrepair and was replaced.
The windpump pumps water from a deep trench on this farm and pumps the water through a pipe which goes under a railway and out into another trench on the other side.
We are very close to the shoreline and the water which is pumped through is pumped again by the local authorities out into the estuary connected to the sea.
The video below shows us lifting the pump out of the windpump as it had some repairs needed, we started the engine pump to keep moving the water out as there was a thaw of snow happening.
Other pumps
After witnessing the positive effects the windpump brought to the land – it is much drier now in winter especially if you have a winter cereal crop growing.
We decided to make another pump but this time have it powered by a small Kubota diesel engine as a standby alongside the windpump.
Although the windpump structure was bought and transported from Australia – we made the pump section ourselves so we had the know-how, so we thought we’ll do it again.
This other engine drive pump sits inside an old metal skip and starts using a key start.
The rotary motion of the engine pulley is converted into an up-down motion by using the gearbox of an old baler we had lying around and the whole thing can run for 24 hrs using a gallon of diesel!
I hope you enjoyed my article – let me know if you have any questions!
Hi Richard.
Very interesting article. How deep and what diameter is your well and is it lined? How large an area does the windpump drain the water from i.e. lower the water table?
What diameter of outfeed pipe do you have attached to the pump?
Kind regards
Glenn
Hello Glenn, the diameter of the pump is around 5 feet and sits in the water about 2 feet. It drains maybe 100 acres on that side of the farm. The outfeed is folded galvanised steel about 1 foot by 1 foot square. Thank you for your comment- you must be considering something like it!
Richard