Stabilising Irrigators

November 2015

Engineering students at Canterbury University solving the problem of wind damaged irrigators

University of Canterbury students have come up with a way to prevent damage to irrigators during high winds in a project prompted by the Foundation for Arable Research.

In the spring of 2013, storms with wind speeds of more than 130 km/hr passed over the country causing widespread damage to agricultural infrastructure. This damage included approximately 800 pivot and lateral irrigators in the Canterbury area with waits of up to six months for repairs. This cost millions of dollars both in damage to the irrigators and loss of production because of time without irrigation.

FAR obtains regular feedback from its farmers throughout the regions, and in this case there were requests for them to get involved in providing a solution for this often recurring problem.

Following up on this, FAR approached the University of Canterbury to look at ways to stop irrigators toppling in high winds.

FAR director of business and relationships Ivan Lawrie said usually FAR research is focussed on agronomy and productivity issues, so heading into mechanical issues was a new area for them. He said FAR had thought that an aerodynamic solution such as fins or foils on the irrigators might have worked.

“But as it turned out it seemed that the simplest solution was the most logical one. It comes from bringing fresh people and fresh minds into an industry they didn’t know anything about.”

A final year project in the Mechanical Engineering Department at Canterbury University saw four students and an Associate Professor specialising in Fluid Mechanics develop a workable solution to the issue. One of the four students is Ben Wright, who worked on the full-year project for his honours degree.

At first, the students researched the topic, looking at current solutions, of which very few existed. They also analysed weather data from the time of the storms. Then the students performed wind tunnel testing and computationally modelled different scenarios to gather a greater understanding of what sort of forces were acting on the machines during these high winds.

The structural integrity of the irrigation systems themselves were also analysed to ensure that any solution developed would not damage the machines.

The solution the project team developed consists of an inflatable water tank connected to a pulley system which lowers the bag to the ground in the case of a major wind event, acting as an anchor to centre pivot or lateral irrigators.

Further computer modelling was used to ensure the idea would work theoretically, and at the end of the year the team ordered all the parts and connected the system to an irrigator on FAR’s Chertsey arable research site where it was demonstrated at their annual crops expo in December.

There are a couple of other solutions available which use similar principles of anchoring but all take time to both put in place and remove. For the Hydrofix system it’s the streamlined filling and emptying process which is the real key.

Ideally, one inflatable tank is used on each span of the machine although some farmers may wish to concentrate on high risk areas such as corner arms.

“We’re still in the development stage at the moment. We have a few different versions of the bag which we are testing to iron out all the issues,” he says.

He says the process benefited both the students and FAR. On one hand, the students were able to build on the knowledge and skills they gained throughout their previous course work, getting experience working on real world engineering problems. And for FAR, a modest investment, some expenses and in-kind help and time got a solution to an expensive problem for a fraction of the cost of going to the industry for a commercial solution.

Now Ben, who had previously worked repairing the irrigators following these storms, is a sales and design engineer for the company which took up the licence, Carrfields Irrigation.

Ivan says the system is very easy to deploy and it can be done by a single person. Work is now underway to automate this process.

A provisional patent is already in place, and licensed to Carrfields Irrigation, an Ashburton based irrigation company, which is developing the solution into a marketable product.

Earlier in the year at the South Island Agricultural Field Days, Carrfields had the HydroFix system on show and began taking expressions of interest for an open field trial. Since then the company has been working with farmers to tailor systems to suit their individual needs.

Development has been going well, with Carrfields staff looking at variations to the original design such as systems to specifically work with corner arms.

Once further testing is completed, Carrfields intend to have the system in place on different machines, with different levels of wind exposure and on different country types in early spring.

FAR is intending to use the royalties from the HydroFix to help fund further research projects by students at Canterbury University.

Ivan says they have a “list of seemingly unsolvable problems that keep cropping up. We take the list to the students, and the proposals go to the university.”

This year students are working on two completely different problems: robotic bird scarers and renewable energy to power on-farm grain driers.