Heat-Shrinking Oven Recirculation for Tall Load Heat Retention

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Solution Overview

Problem

Existing heat-shrinking ovens are energy-inefficient due to significant heat loss and risk of damaging upper film layers, particularly when processing loads taller than the oven compartment height.

Innovation Solution

A heat-shrinking oven with a recirculation system that traps and reuses rising hot air within a box-shaped cabinet, using tilting flaps or flexible seals to allow load passage and a load height sensor to control the opening of the upper wall, ensuring efficient energy use and film protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If heating means are installed on open structures to surround the load, then uniform heat distribution is achieved, but significant heat loss occurs into the environment

Engineering Contradiction:
Improveheat distribution uniformityVSAvoidheat loss
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The patent employs movable screens that can be positioned to enclose the upper part of the load, creating a flexible barrier that traps hot air while allowing heat to reach the film. These screens act as temporary enclosures during the shrinking process, preventing heat escape without compromising the open structure needed for uniform heat distribution.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The movable screens are dynamically positioned - raised during loading and lowered during shrinking. This dynamic adjustment allows the system to transition between open (for loading/unloading) and enclosed (for heat retention) states, optimizing both heat distribution and energy efficiency at different operational phases.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If heating means are installed on open structures, then access for loading is improved, but hot air rises and damages the film waiting to be lowered onto the next load

Engineering Contradiction:
Improveloading accessVSAvoidfilm damage from hot air
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

Movable screens create a protective enclosure over the film storage area, acting as a flexible barrier that blocks rising hot air from contacting the heat-sensitive film while maintaining ease of access during loading operations.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The screens are dynamically controlled to be in place only when needed - lowered during the shrinking operation to protect film, and raised during loading to maintain accessibility. This temporal separation resolves the conflict between protection and access.

Inventive Principle:
Principle #15Dynamics

3Loss of energy

If the oven is configured as an enclosed compartment, then heat loss is reduced, but the load height is limited by the vertical dimension of the compartment

Engineering Contradiction:
Improveheat loss reductionVSAvoidload height accommodation
Core Design Contradiction:
Loss of energyVSAdaptability or versatility

Solution Approach 1:

The oven is segmented into a fixed lower compartment and a movable upper section. The screens can be positioned at different heights or completely raised, allowing the effective heating volume to be adjusted according to load height while maintaining enclosure for heat retention.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The movable screens create a dynamically adjustable enclosure height. During operation, the screens are lowered to enclose the load regardless of its height, providing both heat retention and adaptability to various load dimensions.

Inventive Principle:
Principle #15Dynamics

4Manufacturing precision

If high temperature is used for effective shrinking, then film consolidation is improved, but energy consumption increases

Engineering Contradiction:
Improveshrinking qualityVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent converts the naturally rising hot air, which was previously a source of heat loss and film damage, into a beneficial recirculating heating element. The screens redirect rising hot air along the load, ensuring complete and uniform shrinking while reducing the need for additional energy input.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The enclosure created by the screens maintains continuous contact between hot air and the film surface throughout the shrinking process, ensuring consistent heat application and complete shrinkage without requiring temperature increases or extended processing time.

Inventive Principle:
Principle #20Continuity of useful action

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

The oven minimizes heat loss and protects upper film layers while maintaining efficient shrinking quality across varying load heights, enhancing energy efficiency and shrinking process speed.

Implementation Method 1

The heating means consist of heat shrinking ovens essentially in the form of hot air generators (such as gas burners, or electric generators)

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 2

The heating means consist of heat shrinking ovens essentially in the form of hot air generators (such as gas burners, or electric generators)

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 3

much of the heat is released into the environment, which spontaneously rises upwards

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 4

A heat-shrinking oven with a recirculation system that traps and reuses rising hot air within a box-shaped cabinet

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP4660086A2Heat-shrinking oven with improved energy efficiency
Publication Date: 2025.12.10 OFFICINA MECCANICA SESTESE
  • EP4660086A2 patent drawingFigure 1
  • EP4660086A2 patent drawingFigure 2
  • EP4660086A2 patent drawingFigure 3

AI summary

A shrinking oven (1) for shrinking a shrinkable film on a load to be wrapped (C) is disclosed, comprising a frame (3) on which is mounted vertically movable support frame (43) to which is attached a heating oven (4) equipped with at least a heat generator, at least a blower (41) to convey hot air, at least a distribution lung (42) equipped with a slot to direct hot air to a resting area of said load (C) in which a box-type cabinet open downwards and equipped with side (44) and top (45) closing walls is also mounted on said support frame (43), above said distribution lung (42), and wherein said at least a heat generator is arranged to feed hot air into said distribution lungs (42), arranged in an annular path around a working area corresponding to the perimeter footprint of said load (C), by means of said at least a blower (41), hot air transfer ducts (46) being also provided, which have an inlet end arranged inside said box-shaped cabinet at its top closing part (45) and an outlet end at a blower (41) inlet.