Classic farm machine designed and built by a farmer for a farmer
This is a job shirked by few, yet enjoyed by almost nobody.
As every farmer knows, stirring a lagoon with a quarter million or more litres of raw cow slurry is essential if the contents are going to be pumped or sucked out and spread on the land. At today’s fertiliser costs, every one of those litres is saving something. The standard slurry stirrer has a shaft and propeller sticking straight out from the rear of the tractor, so the tractor has to be parked at right angles to the lagoon.
It’s often a problem, because the lagoon bank is barely wide enough.
Once it’s in position, there’s a reluctance to move the tractor, as a false move will have the machine either sliding into the slurry or rolling down the steep bank.
So the stirrer is often left in one position for hours on end, as the contents of the pit are slowly liquidised.
Yet, the slurry is mixed far quicker and at less cost, if the propeller is moved from time to time, breaking and mixing the crust in different places. For those with this problem, here’s the machine which does the job.
The shaft of the stirrer turns through a total of 140 degrees — 70 degrees either side of the ‘straight back’ position.
And now to the engineering. The power taken by the slurry stirrer is considerable, and too great for the typical “Hardy Spicer” universal joint.
This machine uses two right angle forage harvester gearboxes, one on top of the other. So the drive goes from the tractor PTO into the first box, which is mounted on a frame on the three-point linkage.
The output shaft goes vertically up and connects to a shaft on the second gearbox that’s mounted on a frame that turns it around an axis which is directly in the plane of the connecting shaft.
The two frames are made with strength to take the force of the propeller pushing against them.
The forager gears are designed to take a huge amount of power.
This novel machine was made in 2005 as a workshop project by farmer’s son Robert Davies while at the Welsh ag college at Gelli Aur, and has been in use ever since.
He patented the idea and tried to interest manufacturers in it, to no avail.
While used gearboxes are easy to find, new ones are expensive.
But the machine has much to commend it, in terms of mixing efficiency, safety and fuel use.
It’s a classic farm machine designed and built by a farmer who knows the job and can see a way of doing it better.
This kind of farm engineering which has its base on the farm often has an effectiveness and simplicity which can be lacking in some new machines.
The dangers and inefficiency of doing the job in the regular way are sometimes easier for the younger brain to work on, and Robert certainly excelled in this idea.
I would be delighted to help any farmer or engineer contemplating the task of making a machine like this, and involving Robert as well.
The detailed engineering needed careful thought, but the result was spectacular.
*If you know of an interesting farming innovation which we can pass on to readers, please get in touch through the editor (021-4802365 or farm.ed@examiner.ie).
