Stirling Machine Head Assembly Preventing Regenerator Damage

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Solution Overview

Problem

The high temperature of the braze cycle in assembling Stirling machines can damage the regenerator's structure, affecting its performance and life, while soldering cooler fins in place may reduce efficiency and increase costs.

Innovation Solution

Fixing cooler fins before installing the regenerator allows for high-temperature attachment methods like brazing or welding, avoiding damage to the regenerator and enabling the use of expandable regenerator elements to ensure proper fit and packing density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cooler fins are brazed in place after regenerator installation, then reliable high-temperature joint is achieved, but regenerator structure is damaged by braze cycle temperature

Engineering Contradiction:
Improvejoint reliabilityVSAvoidregenerator damage from high temperature
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The regenerator is installed in the head assembly before the cooler fins are brazed to the casing. By performing this installation in advance, the regenerator is positioned such that it can withstand or be protected from the subsequent high-temperature brazing cycle, thereby achieving reliable joints without damaging the regenerator structure

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The assembly process is segmented into distinct stages: first installing the regenerator, then brazing the cooler fins separately. This segmentation allows the regenerator to be installed before exposure to high temperatures, protecting it while still enabling reliable brazed joints for the fins

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If cooler fins are soldered in place, then regenerator is protected from temperature damage, but joint reliability and heat transfer efficiency are reduced

Engineering Contradiction:
Improveregenerator protection from damageVSAvoidjoint reliability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The regenerator is installed before the cooler fins are attached, allowing the use of high-temperature brazing methods that provide reliable joints and good heat transfer efficiency, while the regenerator's position and timing of installation protect it from temperature damage

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If regenerator is installed before cooler fins are fixed, then high-temperature brazing can be used, but regenerator may be damaged during fin fixation

Engineering Contradiction:
Improvehigh-temperature attachment capabilityVSAvoidregenerator damage during fixation
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The regenerator is installed as a preliminary step before the cooler fins are brazed to the casing. This sequencing allows high-temperature brazing to be used for reliable fin attachment, while the regenerator's established position and the controlled brazing process prevent damage during the fixation step

Inventive Principle:
Principle #10Preliminary 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

This method prevents regenerator damage during cooler fin fixation, maintains high heat transfer efficiency, and reduces manufacturing costs by allowing reliable high-temperature attachment, while ensuring proper regenerator expansion and packing density.

Implementation Method 1

each of the elements is made of compacted random wire... the elements decompress in-situ... adjacent elements can expand onto one another

Methodology Applied
Scientific EffectElastic expansion: Elasticity

Implementation Method 2

receive heat from a burner conducted through the wall of the casing

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

cooler fins... brazed in place... heat transfer through the fins

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP1915524A1A method of assembling the head of a stirling machine
Publication Date: 2008.04.30 MICROGEN ENERGY

AI summary

A method of assembling the head of a Stirling machine. Two sets of fins (3, 4) are fixed within the head casing (1). At least one regenerator element (7) is passed through a central opening in the fins (4) and is located in place between the two sets of fins. The regenerator elements are made from compacted wire and decompress in situ.