Refrigerant Distributor Brazing for Sacrificial Corrosion Protection

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Solution Overview

Problem

The challenge lies in forming a sacrifice positive electrode layer on the surface of a refrigerant distributor with a complicated shape, which is difficult due to its intricate design, and the risk of strength reduction in joined parts from excessive heating during the brazing process.

Innovation Solution

A method involving the application of flux to remove aluminum oxide, followed by the disposition of a zinc-containing aluminum-silicon alloy, which is then heated to form the sacrifice positive electrode layer, while using an aluminum-silicon alloy brazing material for joining, allowing for controlled heating to prevent strength loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a zinc-sprayed aluminum material or aluminum clad material with sacrifice positive electrode layer is used to prevent local corrosion, then corrosion resistance is improved, but the manufacturing complexity and cost increase due to additional spraying or cladding processes

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the sacrifice positive electrode layer formation with the brazing process by using zinc-containing aluminum-silicon alloy brazing material. The zinc in the brazing material forms the sacrifice positive electrode layer on the aluminum surface during the brazing heating process, merging two functions (corrosion protection and joining) into a single process step, thereby eliminating separate spraying or cladding operations

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The zinc-containing aluminum-silicon alloy brazing material serves multiple functions: it acts as both the joining material for brazing the aluminum parts together and as the source material for forming the sacrifice positive electrode layer that provides corrosion protection. This multi-functional material eliminates the need for separate anti-corrosion treatment processes

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Weight of moving object

If the refrigerant distributor is made of aluminum for lightweight and corrosion resistance, then weight and general corrosion resistance are improved, but local corrosion resistance is worsened due to chloride ion attack on the aluminum oxide film

Engineering Contradiction:

ImproveweightVSAvoidlocal corrosion resistance

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The patent creates a composite structure by forming an aluminum-zinc alloy layer (sacrifice positive electrode layer) on the aluminum base material surface through the brazing process. This composite structure combines the lightweight properties of aluminum with the enhanced local corrosion resistance provided by the zinc-containing alloy layer that preferentially corrodes to protect the underlying aluminum from chloride ion attack

Inventive Principle:

Principle #40Composite materials

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 approach enables the convenient, efficient, and accurate formation of the sacrifice positive electrode layer on complex-shaped refrigerant distributors, preventing strength reduction in joined parts and ensuring effective corrosion inhibition.

Implementation Method 1

applying flux that removes aluminum oxide to a surface of the plurality of outflow sections and the distributing section

Methodology Applied

Scientific EffectChemical etching:

Implementation Method 2

forming a sacrifice positive electrode layer on the surface by heating the disposed zinc-containing aluminum-silicon alloy

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 3

an alloy disposing step of disposing a zinc-containing aluminum-silicon alloy on the surface

Methodology Applied

Scientific EffectAlloying:

Implementation Method 4

a brazing step of brazing the plurality of outflow sections with the plurality of outflow pipes, respectively, by heating the disposed aluminum-silicon alloy brazing material

Methodology Applied

Scientific EffectBrazing: Brazing

Data Source

PatentUS10175009B2Method for manufacturing refrigerant distributor, refrigerant distributor manufacturing apparatus, refrigerant distributor, heat exchanger, and air-conditioning device

Publication Date: 2019.01.08 MITSUBISHI ELECTRIC CORP

AI summary

A sacrifice positive electrode layer is formed conveniently, efficiently, and accurately on the surface of a refrigerant distributor having a complicated shape. Further, during the formation of the sacrifice positive electrode layer, the strength in the surroundings of joined parts is prevented from being lowered by excessive heating. Included are: an applying step of applying flux to remove an aluminum oxide to a surface of a plurality of outflow sections and a distributing section; an alloy disposing step of disposing a zinc-containing aluminum-silicon alloy on the surface to which the flux is applied; a forming step of forming the sacrifice positive electrode layer on the surface by heating the disposed zinc-containing aluminum-silicon alloy; a brazing material disposing step of inserting a plurality of outflow pipes into the plurality of outflow sections, respectively, and disposing an aluminum-silicon alloy brazing material on the surface of the outflow sections; and a brazing step of brazing the plurality of outflow sections with the plurality of outflow pipes, respectively, by heating the aluminum-silicon alloy brazing material.