CAN DRYING AIR KNIFE SYSTEM

In line with new recommendations from three leading bodies in the drinks industry, a unique can drying system has been developed by Secomak, manufacturers of drying and cleaning systems. The Metal Packaging Manufacturers’ Association (MPMA), British Soft Drinks Association (BSDA) and the Brewers and Licensed Retailers Association (BLRA) have issued a new Code of Practice relating to environmental stress cracking of aluminium alloy beverage End scores.

The product has been developed in response to new findings on the costs and damage to the drinks industry from stress corrosion cracking, a failure process at the score of aluminium alloy beer and soft drink can Ends. The failure, which typically occurs in shrink-wraps or cartons held in warehouses, leads to the tabs popping out suddenly, and, often means that entire lorry loads of cans are rejected on delivery. This may happen even if only one can has presented with the fault, as the moisture released by tab failures is likely to lead to progressive failure of neighbouring packs.

Secomak’s new drying system eliminates the cause of this failure by removing the moisture and moisture contaminants that may lead to cracking. The fundamental cause of failure is the reaction of moisture with the End alloy at the score region which initiates a localised corrosion process, leading to cracking at the score base and sudden failure. Failure risks through stress corrosion are especially high in hot and humid climates e.g. temperatures above 30ºC, and humidity above 60%rh (relative humidity), a measure of saturation.

The corrosion process is greatly accelerated by the presence of contaminants such as residual salts, mineral oils, alcohols and hexane, which have to be thoroughly washed off can Ends if they are not to create susceptibility to cracking. After this process, in order to minimise further corrosion risks from moisture, it is essential to ensure that bodies and Ends are thoroughly dry prior to packaging. The new recommendations state that moisture should be removed to a maximum average remaining level of 3mg per End using a modern, specifically designed dryer.

Secomak’s new can drying system, which has been developed solely to address this problem, uses novel additional components to the already successful Powerstrip drying system.