Quick Dips

Scanning Wool

New Zealand scientists are setting the pace internationally in adapting airport luggage scanners to increase the marketability of major exports.

New Zealand's merino wool industry will be the first of several to benefit from the latest scanning technology called Dual Energy X-ray Absorption (Dexa).

The Institute of Geological & Nuclear Sciences Limited (GNS) is working with NZ Pac Ltd, a wholly-owned subsidiary of Merino New Zealand, to measure yield and contaminants in fine wool.

The Dexa scanning system will give instant and accurate measurements over whole fleeces without touching them, a milestone for the wool processing industry internationally.

The modified luggage scanner will allow New Zealand's entire merino clip to be graded as it is processed at NZ Pac's new wool-handling facility in Christchurch. The facility is rated the most advanced of its type in the world.

GNS project leader Murray Bartle is working with an American supplier of Dexa luggage scanners to convert the information provided for the customs and security industries into information useful for the fine wool industry.

Similar applications are likely to follow for the meat and coal industries.

"The scanner will give wool yield as a percentage of total fleece weight. It will also pick up contaminants more efficiently than the human eye. This includes pieces of plastic and metal, as well as vegetation and polypropylene string which can be a headache for manufacturers," Bartle says.

Two years of research by GNS using a standard airport scanner showed that Dexa technology can provide rapid and complete information on the composition and contamination of bulky products, including wool and frozen meat carcasses.

Existing quality control methods in the wool, meat, and coal industries involve relatively slow analysis of small samples.

"The speed, accuracy, and efficiency offered by modified luggage scanners will be a boon to many bulk industries where grading and quality control are important."

Bartle's team in Lower Hutt is fine-tuning a new Dexa machine to operate in NZ Pac's Christchurch facility by March 2000. The facility will grade every fleece before shipping to further differentiate New Zealand merino wool from other suppliers.

The hi-tech processing facility will give buyers and manufacturers a more consistent product and farmers will receive more feedback on their breeding programmes and stock management.

GNS became involved with the wool industry in 1993 and took out a provisional patent for grading wool with X-ray scanners when the potential of using Dexa technology became apparent.

The X-ray technology used in luggage scanners is similar to that used in hospitals to measure bone density and as a general diagnostic tool.