Heat Exchanger Header Box Sleeve Brazing Design

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Solution Overview

Problem

Existing heat exchanger solutions for high-pressure refrigerant fluids, such as those in supercritical state in air conditioning systems, face challenges with leakage and brazing issues when connecting inlet and outlet pipes, particularly in withstanding pressures up to 150 bars.

Innovation Solution

A header box design featuring a sleeve with a retaining collar that is brazed to the collector plate, allowing for optimal brazing surfaces and avoiding plating on the sleeve, while enabling parallel connection of pipes within the header box dimensions, and optimizing space without altering the internal arrangement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If pipes are inserted directly into the header box through openings, then the structure is simple, but significant leakage problems occur

Engineering Contradiction:
Improvestructure simplicityVSAvoidleakage prevention
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

A sleeve is introduced as an intermediary component between the pipe and the header box. The sleeve fits into the opening of the header box and receives the pipe, creating a reliable sealing interface that prevents leakage while maintaining structural simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a connection block is machined and brazed via an intermediate plate, then pipe connection is achieved, but a heavy block is used which leads to brazing problems

Engineering Contradiction:
Improveconnection reliabilityVSAvoidbrazing difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The heavy connection block is removed from the design. Instead, a lightweight sleeve is used that fits into the header box opening. This extraction of the problematic heavy block eliminates brazing difficulties while maintaining reliable pipe connection through the sleeve's collar that can be brazed to the header box.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of manufacture

If existing intermediate pieces are used for connecting pipes, then connection is possible, but they are not suitable for withstanding very high pressures up to 150 bars

Engineering Contradiction:
Improveconnection feasibilityVSAvoidpressure withstanding capability
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The sleeve is designed with modified parameters including a collar with optimized dimensions and a retaining means (such as a retaining ring or deformation zone) that enables the structure to withstand very high pressures up to 150 bars. The collar can be brazed to the header box, creating a strong connection that maintains integrity under high pressure conditions.

Inventive Principle:
Principle #35Parameter changes

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 design enhances the structural integrity and sealing of the header box, effectively withstanding high pressures and reducing assembly complications, making it suitable for high-pressure refrigerant fluids in air conditioning evaporators.

Implementation Method 1

The sleeve can be brazed with an optimal brazing surface on the collector plate by its collar

Methodology Applied
Scientific EffectBrazing: Brazing

Data Source

PatentEP1780490B1Header box for heat exchanger
Publication Date: 2009.03.11 VALEO SYST THERMIQUES SAS
  • EP1780490B1 patent drawingFigure 1~2
  • EP1780490B1 patent drawingFigure 3~4

AI summary

The box has a cover (52) and a collector plate (26) equipped with reception openings (28) for inserting heat exchanging tubes. A sleeve (40) is disposed in fluid inlet and outlet openings (34, 36) and comprises a collar (42). The collar is sandwiched between the collector plate and the cover and cooperates with the collector plate for maintaining the sleeve. Fluid inlet and outlet pipes are disposed in the sleeve.