Pictured above: The stainless steel screws on the Ishida Screw Feeder multihead weigher move the sticky product along gently but firmly

An Ishida Screw Feeder multihead weigher installed at Germany's top barbecue-ready chicken producer is delivering huge improvements in the speed and accuracy with which sticky marinated chicken pieces can be weighed.

Pre-marinated chicken for the huge German barbecue market is a product that requires the hygienic handling benefits of fully automated packing, particularly as it is sold in large quantities at the warmest times of year. However, the product is so sticky that it has long resisted attempts to weigh and pack it efficiently and at speed.

Stolle GmbH & Co. KG of Visbek, in Lower Saxony is Germany's leading producer of grill-ready chicken. The company processes fresh and frozen chicken into a range of products, including marinated schnitzels and breast fillets. 

In today's high-volume barbecue market, large retailers specify pack weights, such as 500g, and source them from a number of competing suppliers. To remain competitive, Stolle needed to carefully control product giveaway, making weighing accuracy a major issue.

This led the company to seek something more accurate than the semi-automated linear weighing system they had been using, and one that could deliver higher speeds than 20 weighments per minute, which was not enough to meet demand. 

The solution from Ishida was its Screw Feeder weigher, designed to handle movement-resistant products. Part of Ishida's R-Series, this 14-head model is equipped with screw feeders, made of stainless steel, rather than the more conventional vibrating feeders for each weigh head.

Product falls from the dispersion table at the top of the weigher onto the screws. These rotate gently, driving the product out towards the weigh hoppers in a controlled manner. The rounded cross section of the screws and the flexibility of their spiral structure ensure that the chicken is not crushed or damaged.

Additional aids to keeping the product moving are the weigher's sturdy, non-stick plastic hoppers, which are fitted with scrapers to prevent product build-up.

Stolle's marinated chicken line has speeded up to 35 weighments per minute thanks to the new Ishida. Accuracy too has markedly improved, with giveaway cut by half to between 0.5 and 1.5%.

In addition, the Ishida screw feeder weigher, with its lift-off, drop-on contact parts and its watertight body, perfect for hosing down, enables excellent hygiene with minimum downtime. Full changeover cleaning, only required when there is a change in the marinade being used, takes under 30 minutes.

"Because we work with marinated products," explains Norbert Toben, Stolle's Technical Director "the layout of the weigher is a particular advantage."

The result of the installation, according to Stolle's Marketing Manager Albert Focke, is that the company is now "significantly more efficient". Indeed, although the weigher only functions at full capacity for two thirds of the year, it has paid for itself in less than 18 months.