PRILL SPREADING

Press, Volume CIII, Issue 30562, 3 October 1964, Page 8

PRILL SPREADING

A n tary prill or pellet spreader developed by Airwork (N.Z.) Ltd., has given greatly improved evenness of spread of prills or pellets when they are distributed from the air. The spreader is also understood to have given good results in spreading granulated forms of fertiliser, seed and a systemic insecticide which has been used in trials against aphides which carry barley yellow dwarf virus. Mr C. Brazier, managingdirector of Airwork, said it had been found in earlier experiments with distribution of seed and fertiliser that the heavier seeds, and in particular clover, were concentrated in the centre of a swath. Work aimed at achieving an improved dispersal had been going on for about two years and it had been expedited by the need to develop a method of distributing prills, which had similar characteristics to clover seed, when the problem of residues from D.D.T. super dusts arose. The spreader fits into the base of an aircraft hopper. Mr Brazier says it could be made to fit any aircraft. Prills from a measured orifice in the base of the hopper pass down a central throat onto the centre of a rotating plate, and from there are shot out through a series of hollow spokes, which are inclined at an angle to facilitate the

The plate spins on a ballbearing and the unit is. driven by the force of the slipstream and the forward motion of the aircraft. For each increase in forward speed of 10 miles an hour revolutions increase by about 100. Two of the advantages of the unit are its light weight—about 26 or 271 b—and its low drag,, so that it does not appreciably affect the performance of the aircraft

Under test the-spreader has given an even spread of prills or pellets over a 55ft wide swath. Up to 50 acres can be covered in one run and 150 acres can be comfortably treated ih an hour.