Norway’s major fish feed producer, EWOS, installed an extension to its pellet conveying, packing and palletising lines at Westfield, UK, in December 2004. Headquartered in Bergen, the company carries out extensive research and development work from its main base in Dirdal outside Stavanger.

EWOS has streamlined its process and drastically increased its capacity by adding the second line alongside the first one. As a cost saving measure, EWOS decided to use plastic film that costs around 15% less compared with conventional open mouth bags. The new machine is intended for the new packaging material.

The machinery allows on-line changes in bag length and weight combinations without stoppages whenever product density changes, or when different packing combinations are needed. The new machine uses flat sheet based bagging material in roll stock form which can be easily pre-printed with merchandising details and graphics (something which is not possible on conventional ready-made bags and packaging).

MACHINERY

The new system at EWOS consists of a packing station, bagging line with pneumatic conveying system, feed silos, feed hopper, automatic weigher and Vertical Form Fill and Seal (VFFS) bagging machines, which together can streamline production and extract maximum efficiency from the robot palletiser.

The Chrono-Palt RP robot palletiser requires little space and can simultaneously handle bags, pouches, cartons, boxes or drums mixed in one palletising process. It has a sensor to recognize when the pallet is fully loaded and places an empty one to start the next palletising cycle.

The layout and operation of the robot palletiser and wrapping lines have been completely revised. The new equipment replaces an original packing line that worked on open mouth bags at the plant.

Working together, the new and existing lines can now bag 25t of fish feed per hour.

TECHNICAL DETAILS

A weigh-batching system measures the ingredients before grinders cut them into specified sizes. Once the blending and mixing are over, the moist feed passes through a pellet extruder, followed by drying, vacuum coating with oil and bagging.

The feed raw materials are used in varying sizes from 1.2mm to 6.0mm They contain different amounts of oil, nutrients, pigments and other ingredients to suit the fish species, the their growth stage, habitat and other factors.

The plant produces 1,000 different feeds of different combinations. The two Richard Simon UBM belt-fed net weighers at the weighing and bagging station feed weighed product into the VFFS machines.

In the process of production, the plastic film is fed continuously through the machine. Electrical impulse heaters, forming a hollow tube on the vertical forming tube, weld the two vertical edges of the film. Heat sealers at the bottom first seal the bottom of the tube and the product is filled into the formed bag. During the filling process the bag lowers and, when full, the top is sealed to form an airtight package.

Once the top of one bag is formed and separated from the film stock, the base of another is sealed, taking its place in the continuous process. The complete system is controlled by a central PLC and product flow through the system can be rapidly adjusted to meet customer demands, thus avoiding unnecessary stockpiling or product shortages.

As the company produces so many different products, it was looking for flexibility as an essential feature. Each new production run can require stopping the process to clean and re-fit the extruder, as well as to clean the dryer and cooler. Sometimes a run is as small as 2.5t but even then the extruder is up for cleaning even before the product is through the dryer.

BENEFITS

The Chrono-Palt RP robot palletiser is a flexible palletising system in that it requires minimum space and handles palletising of two different products simultaneously without requiring any changeover time.

SUPPLIER

Chronos Richardson Systems, a business unit of Premier Tech, a Canadian based weighing and packaging specialist, was contracted for the pellet conveying, packing and palletising lines at EWOS.