Krones' NitroHotfill delivers compressed air savings

Turkish tea vendor Dogus Cay produces around 35,000 tons of tea/year in five facilities. The company’s distinctive black tea originates from the coasts of the Black Sea and is distributed all over Turkey.

When Dogus Cay decided to expand its range to include a high-quality ice tea in PET containers, it installed a NitroHotfill line from Krones, rated at 22,500 containers/h. A Contiform 3 blow-moulder produces 250 mL hotfill PET containers weighing just 15 g, on 10 moulds at a speed of 2250 containers/h.

A year after installation, Krones 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, a test run revealed excellent results: the same container quality was produced with savings of 44% in compressed-air consumption — more than 300 Nm³/h. The upgrade is estimated to save around €40,000/year, on a calculated machine running time of 6000 hours/year.

The NitroHotfill option is an alternative to the conventional hotfill process, with control 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 required to compensate for the vacuum pressure with hot-filled products is therefore not required. The process also enables aluminium moulds to be used and significantly reduces the machine’s compressed air consumption.