Columnar Honeycomb Drying via Hot Gas Flow and Correction Mold
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Solution Overview
Problem
The columnar honeycomb formed body for heat exchange members faces challenges in achieving uniform porosity and preventing deformation during drying, leading to prolonged drying times and variations in porosity and dimensional accuracy due to differences in drying rates between the outer sidewall and inner sections, especially with thicker sidewalls that absorb electromagnetic waves inefficiently.
Innovation Solution
A method involving the direct passage of hot gas through the cells of the honeycomb body, housed in a correction mold to suppress deformation, with a wet-bulb temperature adjusted to promote binder gelation and uniform drying, reducing the drying time while maintaining shape accuracy and porosity uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electromagnetic wave drying (microwave or dielectric drying) is used, then drying speed is improved, but uniformity of drying is deteriorated due to preferential absorption by outer sidewall
Solution Approach 1:
The patent introduces a porous coating layer as an intermediary substance on the outer sidewall surface. This coating layer has lower dielectric loss than the inner honeycomb structure, acting as a mediator that redistributes electromagnetic energy absorption. The coating layer absorbs excess electromagnetic energy that would otherwise be preferentially absorbed by the outer sidewall, thereby balancing the drying rate between outer and inner sections while maintaining the efficiency of electromagnetic wave drying.
2Manufacturing precision
If hot air drying is used, then uniformity of drying is improved, but drying time is prolonged
Solution Approach 1:
The patent merges two drying methods by applying a porous coating layer designed to work synergistically with electromagnetic wave drying. The coating layer's properties (porosity, dielectric loss) are specifically optimized to enable the outer sidewall to absorb electromagnetic energy at a rate comparable to the inner sections, thereby combining the uniformity advantage of hot air drying with the speed advantage of microwave/dielectric drying into a single accelerated drying process.
3Reliability
If outer sidewall thickness is increased for heat exchange performance, then heat exchange capability is improved, but drying uniformity is deteriorated due to greater absorption difference
Solution Approach 1:
The patent applies local quality modification by coating only the outer sidewall surface with a porous material having specific properties (lower dielectric loss, controlled porosity). This localized treatment creates a gradient in dielectric properties: the coated outer sidewall has reduced electromagnetic absorption compared to the uncoated inner honeycomb structure, thereby balancing the drying rate across different sections while preserving the thick outer sidewall geometry needed for heat exchange 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
This approach allows for rapid drying of the honeycomb structure with reduced deformation and porosity variation, enhancing productivity and quality stability by ensuring uniform drying and maintaining shape accuracy.
Implementation Method 1
a wet-bulb temperature adjusted to promote binder gelation and uniform drying
Implementation Method 2
allowing hot gas to pass through the cells of the honeycomb body... rapid drying of the honeycomb structure
Data Source
AI summary
A method for drying at least one unfired columnar honeycomb formed body comprising a raw material composition containing at least one raw material of ceramics, water and at least one heat-gelling binder, and cells defined by partition walls comprising flow paths from a first end surface to a second end surface. The method comprising drying the honeycomb formed body by passing hot gas satisfying 0.8≤T2/T1≤3.3, where T1 represents a gelation temperature of the binder (° C.) and T2 represents a wet-bulb temperature of the hot gas (° C.) through the flow paths from the first end surface and out the second end surface, while surrounding the honeycomb formed body with a correction mold to correct the shape of the honeycomb formed body during drying.