PET bottle for hotfill applications

PET bottles can be used for filling soft drinks even when hotfill applications are involved. Specially designed bottles withstand the higher thermal stress involved in hot-filling of soft drinks. For example, the neck finish of the PET bottles is designed in reinforced quality, and the container walls are provided with temperature equalisation areas, known as panels.
At the Ontario II facility of Niagara Bottling, two hotfill lines are up and running, rated at 48,000 containers an hour. The containers arrive at the plant already blow-moulded, are in each line depalletised on a Modulpal single-columm robot, and passed via an AirCo conveyor to the enclosed Variojet rinser/Volumetic filler/capper BLOC. The PET bottles are hot-filled at a product temperature of 83°C. After this, tunnel coolers lower the temperature of the PET bottles to ambient level, before they are labelled by two wrap-around Contiroll HS labellers.

Krones offers two solutions for PET bottles when it comes to hotfill applications

• Handling the classical bottle for hotfill applications with a reinforced neck finish and thread, altered degrees of stretching and vacuum compensation panels, plus a ribbed structure at the bottle’s base.
• Use of the nitro-hotfill process, featuring nitrogen injection dosage at the filler to compensate for volume expansion and shrinkage in the bottle’s headspace during filling. This design feature, familiar from other applications, can now, thanks to Krones’ expertise, be used in bottle design and in the process sequences involved in bottle temperature control for hotfill applications. This produces significant savings in material consumption, and greater freedom when it comes to designing the PET bottle.