The German food company Wernsing Feinkost GmbH, based in Addrup-Essen near Oldenburg, seals 6,000 bags of potato specialties per hour in a production system with 2 x 16 ultrasonic sealing heads.
The food producer has leveraged the knowledge of quality sealing to its advantage since 1997, using ultrasonic sealing modules from Herrmann Ultraschall, an ultrasonic specialist for sealing and bonding plastic materials and films. The quality of sealing with ultrasonic vibrations is particularly high if oily liquids are present in the sealing zone.
The aluminum composite foil is thermally sealed at the sides, while ultrasonic technology is used for the top seal. The bags are sealed in a vacuum at 10 cycles per minute.
Wernsing Feinkost supplies its potato specialties, salads, soups, sauces and deserts to gastronomic companies, hotels, restaurants and retail outlets. The company, which is an affiliate of the Wernsing Food Family, employs around 3,000 people and processes in the region of 400,000 tons of potatoes per year.
“Ultrasonic sealing means that the sealing tools vibrate in an ultrasonic frequency of 20 to 35 kHz, thus melting and closing the sealing layers. The fast ultrasonic vibrations literally ‘knock off’ any feed material from the sealing zone. The result is tight seals and a significantly reduced leakage rate”, says Martin Ponzel, production and technology manager at Wernsing Feinkost.
This saves costs because, if a package leaks, the whole pallet usually has to be disposed of. As product buildup is non-critical in the sealing zone, packaging does not need as much head space, which also saves on material. The thermal load for packaging and feed materials is minimal because the ultrasonic tools indicate minimal temperature increases.
