Separation technology: reliable drives for the food industry

When developing machinery and processing plant for the food industry, how to best puree fruit containing stones, or to separate fish mince from fishbone? And how to remove sinew and gristle from meat without wasting material? Every amateur chef who has already spent hours pressing fruit through a sieve with a spoon or preparing chicken soup knows these questions. In the food industry, these methods have an automated equivalent that makes time-consuming manual labour unnecessary: so-called soft separators are used to gently separate the solid and soft components of a wide range of basic products. Robust, reliable drive technology components that are suitable for the requirements of the food industry are a key prerequisite for a consistently high product quality.

The BAADER group, a manufacturer of machinery and processing plant for the food industry, developed suitable technology for the clean separation of meat and sinews or cartilage more than 40 years ago. Over time, the product range was extended, and now includes soft separators with varying performances that can be used to remove sinew from meat and poultry, to recover meat from fish, to extract pulp from fruit and vegetables, and to unpack food products. In BAADER soft separators, a toothed chain powered by a geared motor is used to move a squeezing belt. The squeezing belt transports the product to a perforated drum and squeezes the soft components through the perforation, while the solid particles remain outside of the drum. An adjustable cylinder allows users to adjust the yield/quality ratio.

This method ensures product quality and minimal temperature increase. Thus, the cell structure of the source product is not destroyed, since the squeezing belt system offers sufficient flexibility. At the same time, unwanted solid components are kept out of the end product during meat processing. Last but not least, the method results in time savings and a standardised final product compared with manual product separation.

BAADER's soft separators were developed in the 1960s and have been constantly optimised since then, for example with regard to the cleaning options. They comply with internationally recognised hygiene standards. In several models, helical bevel geared motors from Nord Drivesystems serve as drive units. One example is the BAADER 605 type, which reaches a maximum performance of approximately 3000kg per hour depending on the hole size in the perforated drum, the feeding type, the product, the feeding temperature and the selected pressure - thereby qualifying for continuous large volume processing. Users can choose a hole diameter of 1.3, 2, 3, 5 or 8mm in the perforated drum, with other diameters available on request.

Custom-tailored drive technology

Nord provides robust helical bevel gear motors for the soft separators - BAADER uses the SK 9016.1, SK 9022.1 and SK 9042.1 gear unit types. These drives owe their long life endurance partly to the Unicase design of Nord's geared motors: the housing, which is made from a single-piece casting with integrated bearing seats, eliminates all sealing surfaces that could deflect under the effect of torque or radial forces. The high-efficiency gear units with durable, wear-free gear teeth also contribute to high reliability during operation. Nord's comprehensive consultation services for customers and users was another factor in the choice of a supplier. Nord has, for instance, also advised BAADER during the preparation of switching over to IE2 motors, helped by extensive experience in the development of efficient drive technology and application-specific energy savings concepts. Martin Schaarschmidt, Sales Manager Separator Technology at BAADER explains: "In Nord, we have found a reliable, competent partner who supplies us with customised drive solutions. Consultation through Nord experts in particular is a great relief, and allows us to focus completely on our own products."

Since June 2011, electric motors must fulfil the stricter energy efficiency requirements of the IE2 efficiency class. Nord has already been supplying IE2 motors for some time. The company has implemented a three-point concept: compliance with the IE2 efficiency class is achieved firstly by the use of more active material, secondly by choosing higher quality sheet metal with less losses, and thirdly with increased copper filling in combination with a simultaneous reduction in the size of the windings. Nord IE2 motors offer various advantages over previous models, including improved efficiency, higher start-up and breakdown torques, decreased slip, and less waste heat with better thermal performance. Compared with their direct predecessor models, IE2-type motors thus offer an increased service life and help save operating costs. If required, the operating range, which has been shifted upwards towards a better efficiency, can be used to continuously operate the new motors at a 150 per cent performance factor. Alternatively, users can now choose a smaller motor type for many applications.

Nord also develops IE3 motors, which have been introduced in the USA in late 2010, with other regions following later. These must ensure an efficiency in-crease of at least 10 per cent compared with the IE2 class. In many cases, this goal can be achieved through the three-point concept. For some IE3 systems, Nord will also make use of different materials. Replacing aluminium with copper as the conductor material for the squirrel cage considerably reduces rotor losses in IE3 systems. In addition, some further measures can be useful in IE3 systems, such as the use of sheet lamination material with lower specific core losses, larger conductor cross-sections in the windings, flux-optimised windings, and smaller windings. Further increases in efficiency can also be achieved with permanent magnet motors and with frequency inverter operation (synchronous motor principle).

For more information about Nord's custom-tailored drive technology, visit the website at www.nord.com.