Multi-Walled Transparent Access Door for Cooling Device Insulation

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Solution Overview

Problem

Conventional cooling devices for displaying chilled products, such as food and beverages, face challenges in maintaining effective cooling while minimizing energy consumption and environmental impact due to the free exchange of chilled air with warmer surroundings, leading to high energy costs and structural impracticality of glass or thick plastic access doors.

Innovation Solution

A multi-walled access door construction with an offset central cavity provides stiffness, insulation, and reduced weight, using plastic materials like PMMA for the walls, which are attached with a transparent adhesive, and optionally includes ventilation openings and LED lighting for enhanced visibility and energy efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a thick glass plate is used for the access door to ensure sufficient strength, then the door achieves adequate structural strength, but the weight becomes excessively high making it impractical

Engineering Contradiction:
Improvestructural strengthVSAvoiddoor weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent applies composite materials by combining multiple plastic layers (first and second walls) with different functional properties. The first wall provides transparency and visibility, while the second wall provides structural strength. This composite structure achieves the required strength without the excessive weight of a single thick glass plate, directly resolving the contradiction between strength and weight.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If a thick plastic plate is used for the access door to prevent deformation, then the door achieves sufficient stiffness, but the weight becomes substantial

Engineering Contradiction:
Improvedoor stiffnessVSAvoiddoor weight
Core Design Contradiction:
Stability of the object's compositionVSWeight of moving object

Solution Approach 1:

The patent segments the door into multiple thin plastic layers (first wall and second wall) separated by a cavity. This segmentation allows each layer to be thin and lightweight while the combined multi-layer structure provides the necessary stiffness through the cavity spacing, preventing deformation without requiring a single thick heavy plate.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a third dimension by creating a cavity space between the first and second walls. This dimensional approach distributes structural requirements across multiple planes, allowing thin individual walls to achieve collective stiffness equivalent to or greater than a single thick plate, thereby reducing weight while maintaining stability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Illumination intensity

If an open access door design is used to provide good visibility of exhibited goods, then the view of products is improved, but energy consumption increases due to free air circulation

Engineering Contradiction:
Improveproduct visibilityVSAvoidcooling energy consumption
Core Design Contradiction:
Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The patent uses a multi-layer plastic composite structure with a cavity that provides insulation properties. This composite construction allows the door to remain transparent for good product visibility while the multi-layer structure with air cavity reduces thermal transfer, thereby lowering energy consumption compared to a single-layer design.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The cavity space between the first and second walls acts as an intermediary insulating layer. This air-filled cavity reduces thermal conduction while allowing light to pass through the transparent first wall, enabling good visibility without the energy penalty of a fully open design.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of manufacture

If a single-layer access door is used to simplify construction, then manufacturing is easier, but insulation performance is insufficient leading to condensation

Engineering Contradiction:
Improveconstruction simplicityVSAvoidthermal insulation
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent segments the door into multiple plastic layers with a cavity between them. While this increases structural complexity, each individual layer remains simple to manufacture from standard plastic sheets. The segmented structure provides superior insulation performance compared to a single-layer door, reducing condensation while maintaining reasonable manufacturing simplicity.

Inventive Principle:
Principle #1Segmentation

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 solution results in a lightweight, energy-efficient access door that maintains product visibility, reduces condensation, and decreases the risk of damage, while minimizing material usage and energy consumption, thus addressing the inefficiencies of traditional cooling devices.

Implementation Method 1

due to the presence of the cavity also insulates well and reduces condensation on the transparent access door

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

due to the presence of the cavity also insulates well and reduces condensation on the transparent access door

Methodology Applied
Scientific EffectCondensation reduction through thermal insulation: Thermal Insulation

Data Source

PatentEP2833760B1Cooling device and access door
Publication Date: 2018.02.28 POLYPLASTIC GROUP
  • EP2833760B1 patent drawingFigure 1A
  • EP2833760B1 patent drawingFigure 1B~1C

AI summary

An access door (1) for use in a cooling device for keeping products chilled and displaying them, in particular food and/or beverages, comprising an at least substantially transparent multiple- walled construction. The multi-walled construction comprises an at least substantially plate- shaped first wall (2) and an at least substantially plane-parallel second wall (3). The walls (2,3) each comprise at least substantially an edge part around them by which both walls are mutually connected. Furthermore both walls (2,3) mutually hold a cavity (5) between the edge parts. Due to the multi-walled construction having an enclosed cavity the access door has a very good stiffness, and moreover due to the presence of the cavity insulates well and reduces condensation on the transparent access door.