Shrink Tunnel Deflecting Device Upward Airflow

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Solution Overview

Problem

Conventional shrink tunnels face issues with non-uniform airflow distribution, leading to potential film overlap and faulty packaging due to opposite flow directions from shaft walls and the floor, resulting in inefficient energy use and package defects.

Innovation Solution

The implementation of a shrink tunnel design with diverting devices within the shaft walls to reverse the flow direction of the shrinking medium from downward to upward, combined with a distribution channel that narrows towards the ends, ensuring uniform airflow distribution and preventing eddy formation, along with adjustable nozzles for optimized hot air supply.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If hot air is blown into shaft walls from above with downward flow direction, then the shrinking medium can be supplied to the interior of the shrink tunnel, but the flow direction becomes opposite to the transport direction causing film overlap and packaging defects

Engineering Contradiction:
Improvehot air supplyVSAvoidpackaging quality
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent inverts the conventional flow direction by introducing a diverting device that reverses the hot air flow from downward to upward direction. This ensures the shrinking medium flows in the same direction as the transport direction, preventing film overlap and packaging defects while maintaining adequate hot air supply to the shrink tunnel interior.

Inventive Principle:
Principle #13The other way round (Inversion)

2Temperature

If shaft walls have nozzle openings on side walls for hot air flow, then uniform heating can be achieved, but energy is wasted due to opposite flow directions creating eddies and inefficient heat distribution

Engineering Contradiction:
Improveheating uniformityVSAvoidenergy efficiency
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The diverting device inverts the hot air flow direction from downward to upward, aligning it with the transport direction. This eliminates counter-flow eddies and energy waste, while the nozzle openings on side walls continue to provide uniform heating distribution across the shrink tunnel interior.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the flow direction parameter of the hot air from downward to upward by introducing the diverting device. This parameter change eliminates energy loss from eddies and improves heat distribution efficiency while maintaining uniform temperature distribution across the shrink tunnel.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If the distribution channel has constant cross-section, then easy manufacturing is achieved, but non-uniform airflow distribution occurs leading to eddy formation and energy waste

Engineering Contradiction:
Improvechannel constructionVSAvoidenergy efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The distribution channel incorporates varying cross-sectional dimensions along its length, with the channel narrowing towards the ends. This local variation in geometry ensures uniform airflow distribution throughout the channel, preventing eddy formation and energy waste, while remaining practical for manufacturing.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design achieves a uniform and efficient airflow distribution, preventing film overlap and improving packaging quality while reducing energy consumption by ensuring the shrinking medium flows upwards, supporting proper film adherence and reducing energy usage.

Implementation Method 1

In the shrink tunnel, the wrapped items are exposed to hot gas, e.g. warm or hot air as a shrink medium, which causes the shrink film to contract so that it clings to the items

Methodology Applied
Scientific EffectThermal heating: Heating

Implementation Method 2

the at least one diverting device for the shrinking medium, by means of which the flow direction of the shrinking medium can be largely reversed. In particular, the first flow direction of the shrinking medium directed downwards within the shaft wall is largely reversed by the at least one diverting device into an at least largely upwards directed second flow direction

Methodology Applied
Scientific EffectFluid flow direction control: Convection

Data Source

PatentEP2554483B1Shrink tunnel
Publication Date: 2015.01.07 KRONES AG
  • EP2554483B1 patent drawingFigure 1
  • EP2554483B1 patent drawingFigure 2~3
  • EP2554483B1 patent drawingFigure 4

AI summary

The tunnel has a transport plane (TE) including a conveyor belt for bottles, which are covered by a shrink film. An outer shaft wall and an inner shaft wall (60a) are arranged on both sides along the belt. The covered bottles are applied with hot air (42) by the shaft walls. The shaft walls include a deflecting device (70) e.g. turning channel (71), for the hot air, where flow directions (SR1, SR2) of the hot air are reversed by the deflecting device. The deflecting device divides the shaft walls into a middle inflow chamber (74) and two outer outflow chambers (76) for the hot air. : An independent claim is also included for a method for shrinking package units to a collection of articles. USE : Shrink tunnel for shrinking package units i.e. shrink films, around a set of articles such as beverage containers i.e. bottles, for combining bundle layers into large packaging units, and for shrinking labels on the articles. Can also be used for cans. ADVANTAGE : The tunnel ensures upwardly directed flows of the hot air, thus supporting upwardly directed overlapping of the package units, and avoiding downward pressing of upwardly directed packaging projections in a false direction by the hot air. The tunnel prevents formation of swirls of the hot air, and avoids hot air supply in determined regions of the tunnel, thus enabling optimal adaptation of the supply of the hot air to the product, and hence reducing energy consumption of the tunnel. DESCRIPTION OF DRAWINGS : The drawing shows a cross-sectional view of an inner shaft wall with a deflecting device. SR1, SR2 : Flow directions of hot air TE : Transport plane 42 : Hot air 60a : Inner shaft wall 70 : Deflecting device 71 : Turning channel 74 : Middle inflow chamber 76 : Outer outflow chambers.