4. Specific constraints for washing PI drums

Before describing the packaging process for drums with built-in plungers, we need to examine the constraints involved.

• The time it takes to pass through the washing stations is short (4 or 5 min) compared to the time it takes to process a bottle (which is close to half an hour). Yet the surface to be cleaned is 200 times larger than that of a 25 cl bottle, for example. It will therefore be difficult enough to obtain a clean surface in such a short time, especially as it will be impossible for the packer to look inside the keg after washing, as he used to do with kegs with removable plungers at the washer outlet and just before filling.

• Breweries have also adopted specific practices, such as filling a keg heated to well over 100°C with a cold liquid, after steam treatment at the end...