Sorting Coins For Silver

Press, Volume CIV, Issue 30688, 2 March 1965, Page 1

Sorting Coins For Silver

The first of six machines which will sort about £1,500,000 worth of half-crowns on their withdrawal from circulation in New Zealand has been designed, built, and tested by the Industrial Development Department of the University of Canterbury and four will be delivered to the Reserve Bank in mid-March. The machine generates a magnetic field and, as coins pass through the air gap in the electro-magnet, eddy currents are generated in the metal of the coins. Half-crowns minted before 1934 contain 50 per cent of silver and later ones are cupro-nickel. The generated magnetic field reacts differently with the original fields in the coins according to their composition. , This gives a force to each W

coin. Cupro-nickel gets a slight deflection and silver a larger one. So as the coins slide down a chute at the rate of 15 a second, they pass into separate bins, virtually of their own volition. When the withdrawn halfcrowns are smelted, it is expected that they will yield about £250,000 worth of silver.

TTie director of the department (Mr T. H. Scott) said that two of these sorters would go to Auckland, two to Wellington ,and one each to Christchurch and Dunedin, roughly in proportion to the number of coins circulating in New Zealand.

By a simple alteration it would be possible for the same 'machines to handle florins, shillings, sixpences, and threepences as they were withdrawn for replacement of decimal currency, Mr Scott said. The department was already working on another problem associated with coin change-over. One hundired pounds’ worth of half-

crowns weigh about 251 b, said Mr Scott, so heavy loads would accumulate. An elevator was being designed to convey sorted coins for check by weighing.