This month, we take a drink of Best Practices knowledge from the ubiquitous PET water bottle. Consumers take them for granted, but they are a miracle of technology, downsized nearly to the point of being a “bag of water” as machinery manufacturers and consumer products companies have waged a relentless effort to reduce the amount of resin used.
Behind the scenes, a high-volume PET bottle factory uses a lot of energy, for drying the massive amounts of material needed for preforms, and to blow mold the containers; for chilled water to cool the molds and compressed air for forming all those bottles.
Drying is especially critical. PET is a hygroscopic resin, meaning that it absorbs water. Improperly dried PET can cause defects in preforms and bottles.
And so is heating, since the injection molded preforms have to be heated up before they can be blow molded. That's the subject of this month's Best Practices report.
In a beverage bottling operation, officials of machinery maker Sidel Group and Nestlé Waters were already well aware the blow molding machines generally account for as much as 70 percent of the total energy consumption of a complete bottling line, according to a case study released by Sidel.
Sidel is the blow molding equipment unit of Tetra Laval Group.
Nestlé Waters and Sidel worked together to cut energy use by more than 1 million euros a year ($1.12 million) — equal to more than 20 ovens in the blow molding machines.
Nestlé Waters launched its energy conservation program in 2010, when it challenged Sidel to rationalize energy consumption for all of its production equipment. Nestlé is a huge player in bottled water, with more than 96 production facilities in 35 countries.
For a company like Nestlé Waters, cutting energy improves its environmental performance — boosting the “green” credentials of plastic water bottles as they face criticism by environmentalists — and keeping the company's operating costs to an absolute minimum. That's the “green” as in money saved.
Sidel has a 50-year relationship with the brands of Nestlé Waters.