Northseafoods Holland BV supplies flatfish to supermarkets in Italy, France, Belgium, Austria, Sweden and The Netherlands. In the company’s plant at Urk, white fish fillets are either frozen and glazed or crumb-coated and IQF (individually quick frozen), then immediately packed.
The length of the product (up to 250mm) and the fragility of the glaze or coating pose some special weighing and packing challenges.
Recently, Ishida Europe was asked to make major modifications to a key packing line, including the installation of a special 14-head weigher, to improve performance and to enable the line to pack bags as well as cartons.
Prior to this project, a 12-head linear weigher discharged the frozen fillets into cartons at a rate of 20 packs per minute. This level of throughput was threatening to limit growth in Northseafoods' business. In addition, the accuracy of the line was no longer acceptable. The key motivation for change, however, was the need for different pack presentations, and the company turned to Ishida Europe for a solution.
The conveyor from the freezing system (-18ºC) brings the product to an inclined belt conveyor which raises it to 6m, where a cross feeder delivers it evenly to the top of the new weigher. Each weighment passes through a metal detector and into a timing hopper.
Underneath the weigher is a special system which can either catch the product in a double-opening timing hopper, leading to the bagmaker, or divert it via a chute to the carton packing line. The system is contained in a frame, which is moved by a pneumatic arm into the chosen configuration.
With the target weights being as low as 270g, and the individual fillets weighing as much as 90g, a reject option was essential for high-speed operation. When packing into bags, therefore, the frame system offers an ideal solution. Any weighment which trips the metal detector or is outside the acceptable weight range causes the frame to move, bringing the chute in line with the outlet and diverting the product via a reject bin. With such a long product, a standard error hopper would be unsatisfactory and could cause product bridging.
When packing carton trays, the chute outlet delivers the product into a dipping funnel to the tray line.
To handle the long, fragile product, the multihead weigher has flat radial feeder troughs with waterfall ends. The 5 litre pool hoppers are fitted with shrouds, while extra large (7 litre) weigh hoppers are used. To further reduce product breakage, the discharge chute is at 45º.
The weigher is mounted on a stainless steel gantry, and surrounded with a temperature-controlled cabinet that keeps it at a steady -5ºC. A special booth is attached, where weigher contact parts can be laid out on racks for rapid cleaning and replacement.
