Grundfos SP Pump does the job and is reliable
New Zealand dairy support farmer, Mike Chaffey, of Rakaia near Ashburton in some of Canterbury’s prime irrigation country, needed a more efficient pump to water his crops.
He was using a line shaft pump, and while it worked okay, he felt he could be irrigating more efficiently and reliably.
The Grundfos Solution
Mike approached the Ashburton authorised Grundfos contractor, Rainer Irrigation, and discussed the problem with Gavin Briggs, the owner. Together they decided to replace the existing line shaft pump with a Grundfos SP125-6 110kW submersible borehole pump able to deliver up to 55 litres of water per second.
The pump and associated equipment was prefabricated at Rainer Irrigation before being transported to Mike’s property at Rakaia where it was installed in about half a day, excluding electricals that were fitted later.
The Grundfos SP was fitted with a 200mm riser pipe and placed down a 104-metre borehole. It has a total head of 142 metres, and feeds water some 300 metres to a massive 10-span pivot irrigation system that, in turn, efficiently irrigates some 80 hectares.
Says Mike: “A reliable water supply is important to me in terms of irrigating my crops, including barley and grasses that are harvested for dairy cattle.
“Depending on the rain, the Grundfos SP pump operates – on average – five days out of seven and generally runs 24-hours a day. The water is clean – almost pure – and has no sand in it, so I expect to get 15,000 to 20,000 hours out of the SP before it needs servicing.”
The Grundfos SP used by Mike is a variable flow system and has a flow metre controller. It also has a transducer that measures how much water is being pumped, and at what rate.
Rainer Irrigation’s Gavin Briggs says that his company installs about 65 Grundfos SP pumps a year.
“They are extremely popular in the Canterbury region,” he says. “In the case of Mike Chaffey, not only is the Grundfos SP more reliable and efficient than his old line shaft pump, but it was cheaper, both in the capital cost and running cost.”