Heat Exchanger Collecting Pipe Arc Transition Stress Reduction

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Solution Overview

Problem

Existing heat exchangers in refrigeration systems suffer from stress concentration and fatigue fracture due to variable loads, which affects their service life.

Innovation Solution

The heat exchanger design includes a collecting pipe with sequentially stacked and connected pipe units, each with a first section of smaller diameter, a second section of larger diameter, and an arc-shaped section between them, allowing for expansion and reducing stress concentration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If pipe units are directly connected with rigid joints, then structural strength is improved, but stress concentration occurs under variable loads leading to fatigue fracture

Engineering Contradiction:
Improvestructural strengthVSAvoidservice life
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent introduces an arc-shaped section between the first and second sections of each pipe unit. This curved transition replaces rigid angular connections, distributing stress more evenly and eliminating stress concentration points that would lead to fatigue fracture under variable loads.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent varies the diameter along the pipe unit length, creating a first section with smaller diameter and a second section with larger diameter. This parameter change allows for expansion allowance during brazing while maintaining structural integrity, and the gradual transition reduces stress concentration.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If pipe units are stacked and connected with insertion, then synchronous sinking during welding is achieved, but manufacturing complexity increases

Engineering Contradiction:
Improvewelding efficiencyVSAvoidpipe unit structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent divides the collecting pipe into multiple pipe units, each consisting of a first section and a second section. This segmentation allows each unit to be manufactured separately and then stacked and connected through insertion, enabling synchronous sinking during brazing while maintaining manufacturing feasibility through modular construction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first section of each pipe unit is designed to be inserted into the second section of adjacent pipe units, creating a nested configuration. This nesting structure facilitates synchronous sinking during welding/brazing while the modular nature keeps manufacturing complexity manageable.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP4067805B1Heat exchanger and refrigeration system
Publication Date: 2025.05.14 ZHEJIANG DUNAN ARTIFICIAL ENVIRONMENT CO LTD
  • EP4067805B1 patent drawingFigure 1
  • EP4067805B1 patent drawingFigure 2
  • EP4067805B1 patent drawingFigure 3

AI summary

The present invention provides a heat exchanger (100) and a refrigeration system (1000). The heat exchanger (100) includes a collecting pipe (10), and the collecting pipe (10) includes a plurality of pipe units (13). The plurality of pipe units (13) are sequentially stacked and connected, and each of the plurality of pipe units (13) includes a first section (131) and a second section (132). A diameter of the first section (131) is less than that of the second section (132), such that the first section (131) of one of adjacent two of the plurality of pipe units (13) is capable of inserting into the second section (132) of the other of adjacent two of the plurality of pipe units (13). An arc-shaped section (133) is provided between the first section (131) and the second section (132) of each of the plurality of pipe units (13), and the arc-shaped section (133) extends to a top of the second section (132) from a bottom of the first section (131), so that the first section (131) is connected to the second section (132).