Small irrigator operates on low water pressure

Press, 23 September 1983, Page 23

Small irrigator operates on low water pressure

A small boom-type irrigator, which operates on a very low water pressure, has been invented by two Ohoka men, John Dugdale and Mike Byrne. The irrigator has been designed for small blocks of land and costs just under $5OOO in a kitset form, complete with hose and fittings. The standard version of the mini-boom irrigator consists of a 26m boom which is carried on a threewheeled trolley. The unit is designed to operate at a pressure of 70 k.p.a. (10 p.s.i.) at the nozzles. It has the capacity to irrigate up to 14 hectares, wet a path in excess of 38m wide, and will travel up to 200 m unattended. Propulsion is provided by a water-

powered winch and the unit self-steers along a winch rope until it stops automatically at the end of a run. Mr Dugdale said they had opted for a very low pressure system which could operate efficiently on a single phase 3 h.p. electric motor rather than requiring a three-phase power supply. Because of the very low pressure requirements of the boom, a smaller than expected pump will supply the required quantity of water. In the case of deep well pumps the saving could be quite substantial. The total weight of the unit is about 400 kg, which enables it to be shifted by hand. The boom is made of galvanised pipe and fittings

supported by a rugged but light truss system. This allows a light trolley to be fitted with automotive wheels and tyres. The unit needs only a standard 50mm alkathene hose because of the low pressure requirements. Mr Dugdale said that over a 14 hectare area, the system could theoretically balance an “evapotranspiration” rate of 3.63 mm a day or 25.4 mm a week. The boom can be rotated to enable the unit to be moved around fixed obstructions. The unit is available in kitset form and costs $4980 from the yard. This includes 200 m of winch rope and 110 m of flexible hose including couplings.