A change in the positioning of a filter plate in his orchard’s irrigation system has ensured almost uninterrupted production and saved on manpower and time for a Western Cape farmer.
Thinus Loock has devised a simple solution to the ongoing problem of blockages in the irrigation system on his farm. Ongelegen’s main business is fruit production on approximately 70 ha, which relies on gravity irrigation from about seven dams.
Thinus, a fourth-generation farmer on his farm near Uniondale in the Eastern Cape of South Africa, says his father, Matie, struggled for many years with the problem of frogs and fresh water crabs getting stuck in the filtration system, causing major disruptions to the irrigation of the orchard.
Frogs, which breed in the dams, end up in the pipes, blocking the filtration system because they clog the valves. This requires time-consuming repairs that result in major delays.
After he started farming in 2009, Thinus realized that they couldn’t afford such major disruptions to their fruit production process as their crop is primarily destined for the export market. Ongelegen also has a warehouse and cold storage facilities for the export fruit.
FILTERS ORIGINALLY PERPENDICULAR
Because of the micro-jets in their irrigation system, they use the Israeli Arkal filtration system to ensure that any impurities, such as sand, are removed from the water. However, like other irrigation farmers, they’ve also taken steps to remove bigger objects, such as frogs, from the system before the water is filtered.
“Even the black bass which I released into the dams were unable to control the increase in the frog population,” says Thinus.
The stainless-steel casings and sieves that were originally used as the primary filters in the pipe from the dam were ineffective. “It took a lot of effort, equipment and manpower to clear any blockages,” he says. Back then, the filters were placed at a 90 degree angle in the pipes and became blocked very quickly.
NEW FILTERS AT A 45 DEGREE ANGLE
Thinus’s solution to the problem was to simply insert a T-piece, with the same diameter as the supply pipe, into the irrigation line. He then attaches a short length of pipe, about 500mm long, to the T-piece. This is shut off at the end by means of a plastic valve.
The secret of this design is the placement of the steel filter plate inside the T-piece. He got an engineering company in Louterwater in the Eastern Cape to make an oval sieve from 3mm stainless steel. He then places the filter plate at an angle of about 45o in the T-piece, with one end in the long part of the T-piece and the other in the short piece that leads to the valve.
The water pressure, which is 1 bar or more, is strong enough to force the dam water through the filter plate, but causes bigger objects to get caught against it and diverted into the short pipe – the unwanted debris then accumulates against the valve. Frogs and crabs are diverted into the pipe without affecting the water flow.
All that is needed is someone to periodically open the valve to rinse out the debris. “We’ve divided the farm into three sections, each with its own ‘water man’ who performs this task,” says Thinus. “This adaptation in our system has been in operation since November last year.”
“Since then there have been no clogged filters or valves, or any unnecessary disruptions. I believe this adjustment could make things easier for quite a few farmers,” says Thinus.
ENQUIRIES: Thinus Loock, email: email@example.com