Heat Exchanger Connecting Pipe Detour for Thermal Stress

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Solution Overview

Problem

Conventional heat exchangers face stress issues due to rapid thermal expansion of the gas header, leading to potential cracking of hairpin tubes, and existing solutions either require excessive space or increase the facility's size by forming auxiliary connecting pipes in a curved shape.

Innovation Solution

Incorporating detour sections in connecting pipes that are bent to extend their length beyond the linear distance between hairpin tubes and the header pipe, allowing for a more compact structure while alleviating stress on the hairpin tubes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If auxiliary connecting pipes are formed into a curved shape to prevent stress, then stress resistance is improved, but the facility size increases and space requirements increase

Engineering Contradiction:
Improvestress resistanceVSAvoidfacility size
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The connecting pipe includes a detour section that is bent into a curved shape, allowing the pipe length to be longer than the linear distance between the hairpin tube and header pipe. This curvature provides stress absorption capability during thermal expansion while maintaining a compact facility footprint, resolving the contradiction between stress resistance and facility size.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Reliability

If the distance between hairpin tube and header pipe is increased to reduce stress, then stress resistance is improved, but the facility size increases

Engineering Contradiction:
Improvestress resistanceVSAvoidfacility length
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The detour section bends the connecting pipe to create a longer effective length between connection points without increasing the linear footprint. The curved configuration allows stress absorption through elongation while maintaining compact spatial dimensions, resolving the contradiction between stress resistance and facility length.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Volume of stationary object

If straight connecting pipes are used to maintain compact structure, then facility size is reduced, but stress resistance deteriorates

Engineering Contradiction:
Improvefacility sizeVSAvoidstress resistance
Core Design Contradiction:
Volume of stationary objectVSReliability

Solution Approach 1:

By incorporating a bent detour section in the connecting pipe, the design achieves both compact facility size and adequate stress resistance. The curved configuration provides the necessary pipe length for stress absorption while maintaining a space-efficient layout, resolving the contradiction between compact structure and stress resistance.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 configuration secures a longer distance between the hairpin tubes and the header pipe, reducing stress on the hairpin tubes during thermal expansion and enabling a more compact facility design compared to linear pipe configurations.

Implementation Method 1

the gas header undergoes rapid thermal expansion upon inflow of a refrigerant at pressure or temperature higher than specified one

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

contraction deformation or extension deformation occurs, which prevents generation of stress due to bending

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2735836B1Heat exchanger
Publication Date: 2016.09.21 MITSUBISHI HEAVY IND LTD
  • EP2735836B1 patent drawingFigure 1~2
  • EP2735836B1 patent drawingFigure 3~4

AI summary

There is provided a heat exchanger (1) which can alleviate the effects of stress due to thermal elongation of branch pipes with a more compact structure. The heat exchanger (1) includes: a heat exchange unit (2) which exchanges heat between a refrigerant flowing through an inside thereof and an external fluid; a plurality of hairpin tubes (3) which is installed at an end of the heat exchange unit (2) and serves as an outlet or an inlet of the refrigerant flowing through the inside of the heat exchange unit (2); a plurality of connecting pipes (4) which has one ends thereof connected to the plurality of hairpin tubes (3), respectively; and a header pipe (5) to which the other ends of the plurality of connecting pipes (4) are connected. Each of the plurality of connecting pipes (4) includes a detour section which is bent such that a pipe length becomes longer than a linear distance between the hairpin tube (3) and the header pipe (5).