The shrink tunnel is one of the most energy-hungry elements in a filling and packaging line. That was precisely what Krones set about to change by design-enhancing their field-proven technology. Their team developed three different energy-saving options, enabling a reduction in consumption by at least 20 per cent while also substantially improving shrink-wrap quality.

Now available: Three additional options for saving energy

The first starting point for upgrading efficiency levels is the bottom chamber. Thanks to integrated shield plates, its width can now be precisely matched to the pack format handled in each case, so that hot air is only activated in those places that actually hold a pack. That makes for a noticeable reduction in both air volume flow and heating output. A plus whose beneficial effect is particularly striking in lines handling disparate pack formats.

The second step in the design upgrade tackles heat distribution in the tunnel’s interior. In order to conclude the shrink-wrap process under controlled conditions, newly integrated heating elements now systematically feed in additional heat from above at the rear of the tunnel. And so, the packs are heated more uniformly, for a more homogeneous shrink-wrap result and lower air consumption.

The biggest efficiency gain comes from a newly developed shaft-wall geometry. The lateral air distributor plates have been redesigned for improved flow dynamics and generate defined air jets going slightly upwards. That produces a properly targeted air draft at the bottom so that the lateral flow can be used more heavily for running the shrink-wrap process. As a result, significantly less hot air needs be blown in from below. Not only does that reduce energy consumption, the properly targeted air flow also stabilises the pack while it is being shrink-wrapped and improves film formation.

The technology used in the new shaft-wall geometry can also be retrofitted to shrink tunnels already in operation. So efficiency levels can be meaningfully upgraded not only in new systems but in existing ones as well.

Savings potential of at least 20 percent

Although each of these three measures can be integrated on its own, implementing the entire package does, of course, maximise the savings potential involved: The new shrink tunnel enables energy consumption to be reduced by at least 20 percent. Depending on the application concerned, it is possible to save even significantly more than that.