Ceramic Filter Glass Seals Thermal Expansion Matching
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Solution Overview
Problem
Ceramic filters used in high-temperature conditions and exposed to alkali aqueous solutions tend to crack, limiting their long-term usability and reliability, especially when used with zeolite separation membranes.
Innovation Solution
A ceramic filter design incorporating glass seals with dispersed ceramic particles (alumina or titania) having a thermal expansion coefficient 90-110% of the glass, and an area occupancy of 35-50%, which inhibits crack generation and enhances thermal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass seals are used to cover the end faces of the porous substrate, then the filtration performance and corrosion resistance are improved, but the filter causes cracks when used for a long period of time in high temperature conditions
Solution Approach 1:
The glass seal is formulated as a composite material containing glass constituent and ceramic particles. The ceramic particles (alumina or titania) with specific thermal expansion coefficients (90-110% of the glass constituent) are dispersed throughout the glass matrix, creating a composite structure that combines the sealing properties of glass with the thermal stability of ceramic particles, preventing crack formation under high temperature conditions
Solution Approach 2:
The invention changes the thermal expansion coefficient parameter of the glass seal by incorporating ceramic particles with specific thermal expansion characteristics. By controlling the particle size (0.5-40 μm), concentration (40-70 mass%), and thermal expansion ratio (90-110%), the glass seal's thermal expansion behavior is modified to match the porous substrate, eliminating thermal stress-induced cracking during high temperature operation
2Stability of the object's composition
If glass seals cover the end faces completely, then the sealing is improved, but the thermal stress concentration causes cracks in the glass seal
Solution Approach 1:
The glass seal uses a composite structure where ceramic particles are dispersed in the glass matrix. This composite material provides both sealing integrity and crack resistance, as the ceramic particles reinforce the glass structure against thermal stress while maintaining the continuous glass phase for effective sealing
Solution Approach 2:
The glass seal incorporates ceramic particles with specific local properties (thermal expansion coefficient 90-110% of glass constituent, particle size 0.5-40 μm) at strategic locations within the seal structure. This local quality enhancement provides targeted reinforcement at stress concentration points while maintaining overall sealing performance
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 filter can be used for extended periods in high-temperature conditions without cracking, maintaining filtration performance and corrosion resistance, even in large honeycomb shapes, by matching the thermal expansion coefficients and optimizing the ceramic particle distribution within the glass seals.
Implementation Method 1
the ceramic particles have a thermal expansion coefficient of 90 to 110% of that of the glass constituent
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A ceramic filter is provided with a porous substrate 3 "made of ceramic and having partition walls 1 separating and forming a plurality of cells 2 extending from one end face 11 to the other end face 12", a separation membrane 21 "made of ceramic and disposed on wall surfaces of the cells 2", and glass seals 31 disposed on the one end face 11 and on the other end face 12 "so as not to cover openings of the cells 2". Ceramic particles having a thermal expansion coefficient of 90 to 110% of that of glass contained in the glass seals 31 are dispersed in the glass seals 31. There is provided a ceramic filter usable for a long period of time in high temperature conditions.