- Analysis & Instrumentation
- Cleaning, Polishing & Grinding
- Coating & Surface Treatment
- Controlled & Modified Atmospheres
- Cutting & Joining
- Freezing & Cooling
- Inerting, Purging & Blanketing
- Melting & Heating
- Petrochemical Processing & Refining
- Pharma & Biotechnology
- Plastics & Rubber Processing
- Process Chemistry
- Water & Soil Treatment
The problem - thin plastic
Liquid nitrogen (LIN) dosing systems are commonly found in the bottling facilities of noncarbonated beverages (water, juices, teas etc.). Dosing systems allow for the pressurisation of bottles, giving them strength for stacking.
The most common bottle material is polyethylene terephthalate (PET). Over the past 20 years, beverage makers have reduced the weight of bottles, to reduce cost and environmental impact. However, doing so has reduced the weight of PET polymers used to produce bottles, resulting in thinner, weaker bottle walls.
After filling, bottles must be stacked so they can be transported to customers. Normally weak bottles at the bottom of a pallet would buckle under the weight of the bottles above, creating unsafe and high-cost product losses.
The solution is to pressurise the bottles. For this, nitrogen is perfect because it is inert and available in a liquid. When liquid nitrogen vaporises, it expands to 682 times its liquid volume.
Dosing systems add a droplet of liquid nitrogen and trap it by immediately capping the bottle.
The trapped droplet expands as it vaporises and increases internal pressure. The pressure increase strengthens the bottle in a process called 'rigidification.'
Liquid nitrogen dosing also offers some product protection from oxygen, which can lead to drink spoilage and lost revenues.