Copper Refrigerant Pipe Coating for Ant-Nest Corrosion

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Copper refrigerant pipes in refrigeration apparatuses are prone to corrosion, leading to leaks, and existing anticorrosive coatings may not effectively prevent ant-nest-like corrosion.

Innovation Solution

A copper or copper alloy refrigerant pipe with an anticorrosive film containing specific compounds like organic sulfonate, polyhydric alcohol-organic acid ester, and aliphatic amine compounds, applied with a metalworking fluid, which is then dried to form a stable and uniform coating that suppresses corrosion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an anticorrosive coating is applied to copper refrigerant pipes, then corrosion resistance is improved, but manufacturing complexity increases due to multiple coating steps and material selection

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple anticorrosive agents (organic sulfonate compound, polyhydric alcohol-organic acid ester compound, and aliphatic amine compound) into a single coating composition that is applied in one step. This merging of multiple protective functions into one coating process reduces manufacturing complexity while maintaining comprehensive corrosion resistance against both acidic and ant-nest-like corrosion.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention uses a composite coating composition containing three different types of anticorrosive agents with complementary mechanisms. The organic sulfonate compound provides general corrosion protection, the polyhydric alcohol-organic acid ester compound specifically targets acidic corrosion, and the aliphatic amine compound prevents ant-nest-like corrosion. This composite approach achieves superior corrosion resistance without requiring multiple separate coating applications.

Inventive Principle:
Principle #40Composite materials

2Reliability

If conventional anticorrosive coatings are used, then general corrosion is suppressed, but ant-nest-like corrosion cannot be effectively prevented

Engineering Contradiction:
Improvecorrosion suppressionVSAvoidant-nest-like corrosion
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies different anticorrosive agents with specific local effectiveness against different corrosion types. The aliphatic amine compound (1.5-200.0 μg/cm²) specifically targets ant-nest-like corrosion, while the organic sulfonate compound (0.1-200.0 μg/cm²) and polyhydric alcohol-organic acid ester compound (0.1-200.0 μg/cm²) address general and acidic corrosion respectively. This localized specialization within a unified coating ensures comprehensive protection against all corrosion types.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention specifies precise concentration ranges for each anticorrosive agent to optimize their protective effects. The aliphatic amine compound is maintained at 1.5-200.0 μg/cm² to effectively prevent ant-nest-like corrosion, while the other compounds are controlled within 0.1-200.0 μg/cm². These parameter specifications ensure that each agent operates at its optimal effectiveness level for its targeted corrosion type.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If multiple anticorrosive agents are combined in high concentrations, then corrosion protection is enhanced, but coating cost and material usage increase

Engineering Contradiction:
Improvecorrosion protectionVSAvoidcoating material usage
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent uses relatively low concentrations of each anticorrosive agent (all within 0.1-200.0 μg/cm², with the aliphatic amine compound at 1.5-200.0 μg/cm²) to achieve effective corrosion protection. This partial action approach is sufficient because the three agents work synergistically, with each contributing its specific protective function. The low concentrations reduce material usage and cost while maintaining effective corrosion suppression through the combined action of all three compounds.

Inventive Principle:
Principle #16Partial or excessive 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

The solution effectively prevents acidic corrosion and ant-nest-like corrosion on the refrigerant pipes, reducing the likelihood of refrigerant leaks and enhancing the durability of the pipes in refrigeration systems.

Implementation Method 1

an anticorrosive film formed on the outer surface of the pipe body... The anticorrosive film includes one or more anticorrosive agents

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP3779347B1Refrigerant pipe, heat exchanger, and method for manufacturing refigerant pipe
Publication Date: 2022.12.14 DAIKIN INDUSTRIES LTD
  • EP3779347B1 patent drawingFigure 1~2
  • EP3779347B1 patent drawingFigure 3~4
  • EP3779347B1 patent drawingFigure 5

AI summary

Provided are a copper-containing refrigerant pipe whose corrosion can be suppressed, a heat exchanger, and a method for producing a refrigerant pipe. A refrigerant pipe includes a pipe body including copper or a copper alloy and an anticorrosive film formed on the outer surface of the pipe body. The anticorrosive film is obtained by applying a coating agent to the outer surface of the pipe body. The coating agent contains one or more anticorrosive agents selected from the group consisting of (A) an organic sulfonate compound, (B) a polyhydric alcohol-organic acid ester compound, and (C) an aliphatic amine compound having 8 to 24 carbon atoms. When the coating agent includes an anticorrosive agent of (C) the aliphatic amine compound having 8 to 24 carbon atoms, (C) the aliphatic amine compound having 8 to 24 carbon atoms is included in an amount of 2.0 wt% or more and 10.0 wt% or less in the coating agent.