Impeller invention shapes
future of spreader demand
Impeller type muck
spreaders are the fastest
growing sector of the
market. Mike Williams
talked to the Cheshire
developed the idea
THE biggest breakthrough in manure spreader technology during the 1960s was the Howard Rotaspreader with its flail chain spreading action. Its simple, reliable design and the ability to deal with solid manure, liquids or any combination of the two made it such a hit that at the height of its success the Rotaspreader accounted for almost 80% of spreader sales in the UK.
But Edward Walley of Cotton Abbots, Waverton, Chester, was one of the few farmers who was not a fan of the flail chain spreader. He liked its versatility, but he thought the work rate was too slow, the power requirement too high and the spread pattern not even enough – so he set about designing a better spreader.
"There was obviously a very keen demand for a universal manure spreader which could handle all types of manure, and the flail chain machines met that demand," he says. "But there were also a lot of faults, and I thought it should be possible to design an improved mac-hine. It took four years to do it."
The spreader he developed used a rotary impeller to spread the manure and had a hopper shaped body with an auger to transfer the muck to the impeller. With the prototype version completed, Mr Walley applied for a patent in 1980, but was just 10 days too late. An American had beaten him to it with a basically similar design.
That was the bad news – but the patents taken out in the US did not cover the UK or other Euro-pean countries and they specified an overshot impeller – discharging the manure over the top of the rotor. Mr Walley had tried both types and preferred an undershot design which is more efficient, he claims, particularly with dry manures.
The Walley design arrived on the market as the West Dual Spreader in 1981. It won the Gold Medal at the Royal Show for the outstanding entry in the machinery awards the following year and during the last 18 years sales of West Dual Spreaders based on Mr Walleys patents total more than 4000.
As well as the impeller design, his patents also cover an anti-bridging device. This is a plate or false wall inside the Dual Spreader, which moves mechanically while the machine is working. The device prevents large lumps of solid manure forming a bridge between the vee-shaped sides of the spreader body, which could stop the manure from reaching the auger.
Kidd Farm Machinery also built an impeller type machine based on Mr Walleys undershot rotor design. It was called the Kidd Tankaspread, and production was taken over by Parmiter last year.
Michael Matts, general manager of Harry West, says the Dual Spreader is easily the top selling machine in the impeller sector of the UK muck spreader market, and it is also the best selling machine in the West product range.
Because of the patent situation, other manufacturers have been able to move into the UK market with impeller spreaders based on the American overshot design. The list includes Abbey, Dowdeswell, Malgar and Shelbourne Reynolds – which took over the Econ design.
The success of the Dual Spreader and the growing range of impeller machines available from other manufacturers is reflected in a shrinking market share for the flail chain spreaders based on the original How-ard Rotaspreader design. Agricul-tural Engineers Association figures show flail machines are still ahead, but impeller spreaders are closing the gap in spite of big price differences favouring the flail spreaders.
More confirmation of the increasing success of impeller machines comes from companies such as Dowdeswell, which have cut the number of flail models they produce and expanded the range of impeller machines. Meanwhile, Mr Walleys undershot impeller has found favour in the US. An American manufacturer bought the rights to his design, and is building spreaders with the undershot impeller.
Mr Walley still finds time from running his 300 dairy cows to continue his career as part-time inventor. As well as the impeller spreader – or at least the undershot version of it, he also developed the paddle mixing system used on the West Hi-Feeder mixer/feeder wagon in the 1970s, he designed a chopping mechanism used on Kidd straw choppers, and his range of zero grazing equipment is on the market through Zero, a company run by his son.
There is also another muck spreader development on the way. Mr Walley has designed and patented a self-filling mechanism for impeller machines which, he says, will make manure spreading a one-man, one-tractor job.
"It is a hydraulically operated grab for slurry or solid manure," he says. *