Feature

Picking a Winning Bunch

By Dr Garth Cambray

The Vezier system, a South African invention is revolutionizing the way grapes are sorted, increasing the profitability and productivity of the table grape industry. A clever marriage of object recognition technology and conveyer belt decision making signals allows packaging lines to save up to 20% on lost grapes and 60% on labour. This article is part of a series focusing on technology inventions from southern Africa.

Bunches of grapes being cut into rough sizes and sorted for defects.

In 2001 Bernard van Zyl realized the need for a grape sizer system for grape packing. In other fruit industries, for example the citrus industry, fruit sorting machines grade fruit on their size amongst other things, and then sort them accordingly. Different clients require different fruit sizes, hence sorting increases the value of the fruit crop. For grapes this is a more difficult problem as a grape bunch is composed of many individual smaller units each of varying size and colour. Bernard proposed the concept of sorting grapes on size, colour and bunch weight, but was generally discouraged by the industry as this seemed like an impossibly complicated, and hence expensive, task.

Undiscouraged, he set to work and after 3 more years a prototype was developed. 

Placing bunches into buckets.

So how does the Vezier system work? Well, first, grapes are brought into the pack house and preliminarily sorted by hand removing damaged bunches. Grapes are then cut into bunches of roughly a specific desired size and placed into cups on a conveyer belt. Each bunch is then weighed accurately to 1 gram and the computer monitoring system records the weight and the cup number. A camera then takes a picture of the bunch in the cup, works out average berry size and colour and adds this information to the weight. The computer now has an exact idea of what is in that cup, and 10 others in front of it and behind it.

The Vezier system weighs and measures the grapes

If the pack operator tells the packing line that packs of 4 kilograms are needed, the computer begins calculating how to make up each pack with the cups available. The packing line has 8 packers on one side of the conveyer belt and 8 on the other. In front of each packer are lights. Red lights signal a packer to take a bunch and place it in the pack. A green light signals that that is the last bunch for that pack and that the pack must be removed and closed and a new pack started on. In this way the packing line is able to very accurately ensure that the package is within the correct weight range. In other packaging lines this is very difficult to do, hence on a 4kg pack generally 200 grams extra is added to ensure that at least 400 grams is packed, so that out of every 20 packed, one pack is lost. By accurately controlling the packing system savings of 10-20% are possible.

Another handy operation the Vezier packing line can perform is to size grapes, as well as sort them on colour. Consequently if a client orders grapes that are packed in a punnet with two colours, the system can ensure that the punnet will look attractive with similar sized berries, and can add value to the punnet as the client will be able to sell it for more, and is therefore willing to pay more for it.

In Egypt grapes ripen and are ready to be exported about 4 weeks earlier than competing products from the EU. Egyptian packers need maximum productivity and quality to compete in the EU market. The marketing director, Pieter Burger, explained that the Vizier system has sold one unit in the Egyptian market which has been so successful that it recouped its US$85 000 cost in one season. 

The light system guides packing into punnets

In South Africa an additional four systems have been sold for the upcoming season. The Vizier system is also potentially of great use in major grape producing nations such as Chile, the USA and India. In an increasingly competitive quality driven global market, the Vezier system is a clever invention that is developed within a uniquely South African context. 

More information:

  Contact Bernard van Zyl Bernard@vizier.co.za 

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