Insulating Layer Moisture Barrier Exhaust Gas Processing
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Solution Overview
Problem
Conventional exhaust gas processing devices face issues with electrical short-circuiting and insufficient heating due to moisture absorption by the inorganic mat member, leading to decreased insulation properties and reduced effectiveness in treating exhaust gases, especially under high humidity conditions.
Innovation Solution
A densely formed insulating layer with a thickness of 20 μm to 400 μm is applied to the inner surface of the cylindrical metallic member, comprising a glass layer and a mixed layer of amorphous binder and crystalline metal oxide, which prevents moisture intrusion and maintains high electrical resistance, ensuring effective insulation and heat distribution within the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an inorganic mat member is used for insulation in the exhaust gas processing device, then insulation properties are improved under dry conditions, but electrical resistance decreases and short-circuiting occurs under high humidity conditions due to moisture absorption
Solution Approach 1:
A resin-coated porous film is introduced as an intermediary layer between the inorganic mat member and the exhaust gas. This film acts as a moisture barrier that prevents water vapor from reaching and being absorbed by the inorganic mat member, thereby maintaining its insulation properties under humid conditions while allowing the mat member to continue providing thermal insulation
Solution Approach 2:
The insulation structure is transformed into a composite system combining the inorganic mat member with a resin-coated porous film. This composite structure leverages the thermal insulation capability of the inorganic mat while the resin coating provides moisture resistance, creating a multi-functional insulation layer that addresses both thermal and electrical requirements
2Volume of moving object
If the insulating layer is made thinner to reduce device size, then device compactness is improved, but insulation effectiveness and electrical resistance decrease
Solution Approach 1:
A resin-coated porous film is used as a thin insulating barrier that provides effective electrical insulation despite its minimal thickness. The film's porous structure combined with resin coating creates a moisture-resistant barrier that maintains insulation effectiveness without requiring substantial thickness, enabling compact device design
3Productivity
If moisture is absorbed by the inorganic mat member, then the material utilization is maximized, but electrical conductance increases leading to short-circuiting and reduced heating efficiency
Solution Approach 1:
The resin-coated porous film serves as a protective intermediary that prevents moisture from reaching the inorganic mat member. This eliminates the harmful effect of moisture absorption while preserving the mat member's structural integrity and insulation function, preventing electrical short-circuiting and maintaining heating efficiency
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 electrical short-circuiting and maintains adequate insulation even under high humidity, allowing for efficient resistance heating and effective treatment of exhaust gases, ensuring the catalytic agents on the honeycomb structure are activated for proper pollutant conversion.
Implementation Method 1
maintains high electrical resistance, ensuring effective insulation
Implementation Method 2
allowing for efficient resistance heating and effective treatment of exhaust gases, ensuring the catalytic agents on the honeycomb structure are activated
Data Source
AI summary
An exhaust gas processing device includes a cylindrical metallic member and an insulating layer. The insulating layer has a thickness of about 20 μm to about 400 μm and is densely formed such that no through pores exist in a thickness direction of the insulating layer. The insulating layer is provided on an inner surface of the cylindrical metallic member.