Bulged-Header Heat Exchanger Assembly Without Brazing

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional heat exchangers face increased production costs and quality control challenges due to the need for brazing, which requires expensive equipment and makes it difficult to ensure proper jointing, and have complex structures with many members that complicate the manufacturing process.

Innovation Solution

A heat exchanger design featuring a bulging portion with a cylindrical circumferential wall and end wall, where heat transfer tubes are inserted and welded, and a header with a flange for welding to the bulging portion, allowing for a simplified assembly process using welding instead of brazing, reducing the number of components and facilitating quality control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If brazing is used to joint the auxiliary member in the bulging portion, then jointing strength is improved, but facility cost and production cost increase due to requiring vacuum furnace equipment

Engineering Contradiction:

Improvejointing strengthVSAvoidfacility cost

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent replaces the thermal process of brazing with a mechanical welding process. The auxiliary member is designed with a protrusion that fits into a recess of the bulging portion, creating a mechanical interlock that can be joined by welding instead of brazing. This substitution eliminates the need for expensive vacuum furnace equipment while maintaining joint strength.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If brazing is executed in the case, then jointing is achieved, but quality control becomes difficult as it is hard to check whether brazing is appropriately done

Engineering Contradiction:

Improvejointing reliabilityVSAvoidquality control difficulty

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent replaces the concealed brazing process with a visible welding process. The protrusion-recess mechanical interlock design allows the welding operation to be performed and inspected from outside the case, enabling proper quality control and verification of joint integrity without difficult internal inspection.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If a conventional heat exchanger structure with many members is used, then manufacturing flexibility is improved, but device complexity and production cost increase

Engineering Contradiction:

Improvemanufacturing flexibilityVSAvoidstructure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the auxiliary member and the bulging portion into a more integrated structure. The protrusion of the auxiliary member directly engages with the recess of the bulging portion, reducing the number of separate components and simplifying the overall structure while maintaining manufacturing flexibility through the modular design.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent segments the heat exchanger into distinct functional modules: the case with bulging portion, the auxiliary member with protrusion, and the heat transfer tubes. This segmentation allows for independent manufacturing and assembly of each component, providing manufacturing flexibility while reducing overall structural complexity through standardized interfaces.

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 reduces production costs by eliminating the need for expensive brazing equipment, simplifies the assembly process, and ensures proper jointing, enhancing the efficiency and reliability of the heat exchanger while preventing leakage and crevice corrosion.

Implementation Method 1

the side wall of the case is constituted with a metal plate, and the bulging portion is integrally formed with the side wall by press-working

Methodology Applied

Scientific EffectPress-working: Cold-forming

Implementation Method 2

a plurality of heat transfer tubes, a case having at least one side wall and housing the heat transfer tubes

Methodology Applied

Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 3

Ends of the heat transfer tubes are inserted into the penetrating holes, respectively, and are jointed with the end wall. The header has a hollow main body having an open edge forming an opening corresponding to the bulging portion, and the opening of the header is blocked by the end wall by fitting the open edge onto the circumferential wall

Methodology Applied

Scientific EffectWelding: Welding

Data Source

PatentUS9970716B2Heat exchanger and production method thereof

Publication Date: 2018.05.15 NORITZ CORP

AI summary

The heat exchanger HE comprising a case 2 housing a plurality of heat transfer tubes 1 and a header 3 having a hollow main body 30 with an open edge 33. A side wall 21 of the case 2 is provided with a bulging portion 22 having a cylindrical circumferential wall 22a bulging out of the case 2 and an end wall 22b which blocks a tip portion of the circumferential wall 22a. Each end of the heat transfer tubes 1 is inserted into a penetrating hole 22c provided for the end wall 22b of the bulging portion 22, and is jointed to the end wall 22b, and the open edge 33 of the header 3 is fitted onto the circumferential wall 22a of the bulging portion 22, thereby forming a chamber 36 communicating with the inside of each heat transfer tube 1. Therefore, it is possible that the number of the members of the heat exchanger HE is reduced, the configuration is simplified, and the heat exchanger HE is easily manufactured at low cost.