NitroHotfill process – hot-filling in PET

With the NitroHotfill process, Krones offers an interesting alternative to the conventional hotfill process in PET bottles. Process control is based on the new Relax-Cooling process (RC). By dosing nitrogen into the bottle shortly before the capper, the bottle is subjected to a positive pressure of 1.5 to 2 bar, which compensates for a volume shrinkage in the hot-filled product downstream of the recooler, thus preventing any deformation in the bottle due to underpressure. The process can be used for producing PET bottles in the Contiform H stretch blow-moulding machine.

Hot-filling – advantages of the NitroHotfill process

• The panel design of the PET bottles required hitherto for equalising the vacuum pressure in the case of hot-filled products is no longer needed.
• The most inexpensive aluminium moulds with a shell system can be used, which substantially reduces the change-over times for the aluminium moulds. 
• The NitroHotfill technology enables savings to be made in terms of the PET material and the blow-air, together with increased output in the stretch blow-moulding process and a higher speed for the line as a whole.
• Inexpensive labelling solutions can be used in comparison to the processes required in traditional hotfill operations. 
• The internal pressure enables the bottles to be more effectively spaced and lane-guided on the conveyors.
• Since panels are no longer required, the bottles’ design can be more responsively tailored to the marketing concept involved.

The maximum filling temperature for the product is 87°C for the monobloc version and 85°C for air-conveyor-link configurations. For hot-filling in the NitroHotfill process, the PET bottle is produced with a specially developed and patent-protected petaloid base design. The NitroHotfill technology can also be retrofitted to many of Krones’ hotfill lines.