Insulating Layer Alkali Metal Limit for Exhaust Gas Treatment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing tubular members for exhaust gas treatment devices face issues with electric leakage and the generation of environmentally hazardous substances due to reactions between the insulating layer and the metal components at high temperatures, which affect the purification performance.
Innovation Solution
A tubular member with a metal main body and an insulating layer containing glass with an alkali metal element content of 1,000 ppm or less, which has a pressing deformation temperature of 600°C or more, is used to prevent electric leakage and reduce hazardous substance generation, featuring a chromium content in the metal body and specific glass compositions including silicon, boron, magnesium, barium, and other elements for enhanced durability and adhesiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating layer containing glass is formed on the inner peripheral surface of the can, then electric leakage is prevented, but environmentally hazardous substances are generated due to reaction between the glass and metal components at high temperature
Solution Approach 1:
The invention changes the chemical composition parameters of the glass in the insulating layer by strictly limiting the content of alkali metal elements to 1,000 ppm or less. This parameter change prevents the glass from reacting with chromium in the stainless steel can at high temperatures, thereby eliminating hazardous substance generation while maintaining electrical insulation functionality.
Solution Approach 2:
The invention applies local quality by creating a specific compositional region within the glass material where alkali metal elements are constrained to 1,000 ppm or less. This localized compositional control ensures that only the insulating layer in contact with the metal can has the modified properties necessary to prevent harmful reactions, while other parts of the system remain unchanged.
2Ease of manufacture
If the glass in the insulating layer has high alkali metal element content, then the insulating layer has good forming properties and adhesiveness, but the insulating layer reacts with metal components at high temperature to generate hazardous substances
Solution Approach 1:
The invention optimizes the chemical composition parameters of the glass by setting specific ranges: alkali metal elements ≤1,000 ppm, silicon dioxide 30-70 wt%, boron trioxide 10-40 wt%, and magnesium oxide 5-20 wt%. These parameter changes achieve a balance between manufacturability (adequate forming and adhesion properties) and environmental safety (no hazardous reactions at high temperature).
Solution Approach 2:
The invention creates a composite glass material with a specific multi-component composition including silicon dioxide, boron trioxide, magnesium oxide, and controlled alkali metal content. This composite formulation provides both the necessary processing characteristics for insulating layer formation and the chemical stability required to prevent hazardous reactions with metal components at exhaust gas temperatures.
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 suppresses the generation of environmentally hazardous substances and maintains electrical insulation and adhesiveness even at high temperatures, ensuring stable exhaust gas treatment performance.
Implementation Method 1
an insulating layer (typically containing a glass component) on an inner peripheral surface of the can
Implementation Method 2
the glass of the insulating layer may react with a constituent component of the can under high temperature to generate an environmentally hazardous substance
Implementation Method 3
the honeycomb structure itself is caused to generate heat by energization, to thereby increase the temperature of a catalyst supported by the honeycomb structure to an activating temperature
Data Source
AI summary
A tubular member for an exhaust gas treatment device according to at least one embodiment of the present invention includes: a tubular main body made of a metal; and an insulating layer formed at least on an inner peripheral surface of the tubular main body. The insulating layer contains glass, and the glass has a content of an alkali metal element of 1,000 ppm or less.