Clever solution to pivot problem

 Responding to growers’ requests to find a way to stop pivots and laterals blowing over, as hundreds did in September 2013, the Foundation of Arable Research sought the help of final year mechanical engineering students at the University of Canterbury.

The result is a patented water-filled tote bag design that can be deployed within 30 minutes of a high wind warning, possibly with no more effort than pressing a button on a mobile phone. What’s more, the simplicity of it suggests when commercialised the cost shouldn’t be too high either.

It’s envisaged a water bag will need to be fitted to every other span of a pivot. When not in use it’s rolled up and held high, out of reach of stock, under the centre of a span. When needed, 1500L of water is pumped in, pulling the giant bag down to anchor the pivot until the wind danger has passed.

“We believe our solution’s stable to about 160kmh. That’s about twice what was experienced in the spring [wind] storms,” Tom Addis told last week’s FAR Crops 2014 event.

Addis was one of a team of four students who worked on the project with the guidance of associate professor Mark Jermy. Crops 2014 was the first time they’d been able to assemble the design since getting the specially modified helicopter water-bomb bag from the manufacturer.

“It goes under a helicopter… so we’re pretty happy it will take its own weight,” Addis said in response to questions as to whether the tethers from the pivot to the bag would tear it.

Jermy acknowledged the angle of the strops was not ideal and the design is still being worked on.

Another field day visitor asked what would happen if the bag needed filling when the power was off, as it could well be in a wind storm. FAR chief executive Nick Pyke said that would be one of the things people would have to consider if they wanted a system like the water-bag design. “A lot of irrigation systems are gravity fed and some people have generators, but we don’t expect this to be the solution for you if you are 100% reliant on power.”

While he didn’t mention it, weather forecasts would likely give operators time to deploy the bags before the power went off too.

The students noted a problem with less-mobile anchor points such as concrete blocks at a certain point on a pivot’s rotation or lateral’s travel: damage may occur before the machine can be moved round to them. They’re also a permanent obstacle onfarm, whereas the bag is simply emptied when the wind risk has eased. As the water drains out, counterweights lift the bag back up under the pivot.

“It’s designed to lock at 1m above ground to allow the water to fully drain out and so you can [roll] it up for storage.”

Pyke said now the design is patented they’re talking to firms that might take it to market, with a proviso that whoever picks up the design and runs with it has to commercialise it quickly. “One company we’re talking to is pretty interested.”

Asked about dairy input into the financing of it, he said it had been discussed but there hadn’t been any, joking that perhaps when it’s commercialised dairy farmers should pay “three times the price for it,” seeing they generally don’t pay FAR levies. “But I think we’d find some of these dairy farms would very quickly have an acre of barley!”

• More from Crops 2014 in Rural News December 16.