High compressed-air savings at Dogus thanks to Krones’ NitroHotfill

The Turkish tea vendor Dogus Cay produces around 35,000 tons of tea per year in five facilities in Rize plus a packaging plant in Ordu. The black tea from the coasts of the Black sea, with its distinctive taste, is distributed all over Turkey. Now the company has also begun to produce high-quality ice tea in consumer-friendly PET containers. In 2015, at its facility in Izmir/Ödemis, for this purpose, Dogus Cay started up a NitroHotfill line from Krones AG, Neutraubling, Germany, rated at 22,500 containers per hour. A Contiform 3 blow-moulder here produces 250-millilitre hotfill PET containers weighing just 15 grams on ten moulds at a record speed of 2,250 containers per hour and cavity.

One year after installation, a Krones team conducted a trial on site to improve the line’s compressed-air system. Following an upgrade and a simple optimisation job on the Contiform 3, the line went back into normal operation. A test run revealed exceptionally good results: with the same excellent container quality, savings of 44 per cent in compressed-air consumption were achieved in comparison to the status before the upgrade, more than 300 Nm³/h. Future savings may prove to be even higher if larger containers are used in the upcoming months. The upgrade saves real money, around 40,000 euros a year, given a calculated machine running time of 6,000 hours per annum.

Attractive alternative to the conventional hotfill process

By developing the NitroHotfill option, Krones is offering a financially attractive alternative to the conventional hotfill process, with control here is based on the relax-cooling (RC) process. By installing a nitrogen injection dosage feature just upstream of the closer, the bottle is pressurised. The positive bottle pressure compensates for the volumetric shrinkage of the product downstream of the cooling unit and accordingly prevents underpressure-related deformation of the bottle. The panel design hitherto required to compensate for the vacuum pressure with hot-filled products can thus be dispensed with. The process also enables aluminium moulds to be used, and dramatically reduces the machine’s compressed-air consumption. The NitroHotfill technology can be retrofitted to many Krones hotfill lines as well.