Heat Exchanger Frame Design for Paper Element Contraction Control

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Solution Overview

Problem

Heat exchange elements made of specially processed paper tend to contract due to long-term use, causing deformation and leakage between supply and exhaust air flows, which affects ventilation and heat exchange efficiency.

Innovation Solution

A heat exchanger design with movable frame members connected to cover members via sliding protrusions and recesses, allowing for perpendicular movement to accommodate contraction, preventing disengagement and maintaining airtightness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If frame members are fixed to cover members to protect corner portions and ensure airtightness, then structural stability and sealing are improved, but the frame members deform and disengage when the heat exchange element contracts over time

Engineering Contradiction:
ImproveairtightnessVSAvoidframe member stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The frame members are designed to be movable relative to the cover members, allowing them to dynamically adjust their position as the heat exchange element contracts or expands. This dynamic capability enables the frame members to maintain contact and sealing with the heat exchange element throughout its service life, preventing disengagement and airflow leakage while accommodating dimensional changes.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the heat exchange element is made of specially processed paper for heat exchange functionality, then heat exchange efficiency is improved, but the element contracts due to long-term use from repeated drying and wetting

Engineering Contradiction:
Improveheat exchange efficiencyVSAvoidservice life stability
Core Design Contradiction:
ProductivityVSDuration of action of moving object

Solution Approach 1:

The movable frame members accommodate the dimensional changes of the paper-based heat exchange element during its service life, allowing the element to maintain its heat exchange functionality while the frame members adjust to its contraction and expansion cycles.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The design anticipates the contraction of the heat exchange element over time and provides accommodative movement capability in advance, preventing disengagement and sealing failure before they occur.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Ease of manufacture

If the frame members are rigidly fixed to maintain structural integrity, then manufacturing simplicity is improved, but airflow leakage occurs when the heat exchange element contracts

Engineering Contradiction:
Improveassembly simplicityVSAvoidsealing reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The movable frame members are designed with simple movement mechanisms that allow them to adjust to heat exchange element contraction while maintaining sealing, achieving both ease of manufacture and reliable sealing without complex mechanisms.

Inventive Principle:
Principle #15Dynamics

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 design effectively suppresses airflow leakage and maintains airtightness between supply and exhaust air flows, even with heat exchange element contraction, ensuring consistent ventilation and heat exchange efficiency over time.

Implementation Method 1

heat exchange element (21) in a prism shape having a square cross-section taken along a plane perpendicular to an axial direction X of the heat exchange element (21)

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

heat exchanger to perform heat exchange between a supply air flow and an exhaust air flow

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3418663B1Heat exchanger and heat exchanger ventilation device
Publication Date: 2020.08.19 MITSUBISHI ELECTRIC CORP
  • EP3418663B1 patent drawingFigure 1~2
  • EP3418663B1 patent drawingFigure 3
  • EP3418663B1 patent drawingFigure 4

AI summary

A heat exchanger 20 includes a prism-shaped heat exchange element 21, a plurality of frame members 22 mounted to sides of the element in a one-to-one relationship, the sides extending along an axial direction of the heat exchange element 21, and cover members 23 each covering an end face of the element, the end face being perpendicular to the axial direction of the heat exchange element 21. The frame members 22 are connected to each of the cover members. Gaps 25 and 26 for allowing movement of each of the frame members 22 along a direction perpendicular to the axial direction of the heat exchange element 21 are provided at each connecting portion at which the frame members 22 are connected to the cover member 23. Thus, it is possible to move the frame members 22 along with deformation of the heat exchange element 21.