Cement Patty Plugging for Honeycomb Body Uniformity
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Solution Overview
Problem
Existing methods for plugging honeycomb bodies with cement often result in voids, leading to non-uniform blockages and reduced efficiency in particulate filters due to high viscosity and entrained air during mixing and dispensing.
Innovation Solution
A method involving a plugging mixture of inorganic particles, an inorganic binder, and an organic binder is mixed and dispensed at temperatures above the hydration point, then cooled below it to form a cement patty, which is pressed into honeycomb channels, minimizing air pockets and ensuring uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If cement is mixed and dispensed at high viscosity, then the mixture maintains structural integrity during handling, but air pockets and voids are entrained leading to non-uniform blockages
Solution Approach 1:
The patent applies parameter changes by controlling the temperature of the cement mixture to manage viscosity. The mixture is maintained at a temperature above the hydration point temperature during mixing and dispensing to keep viscosity low and prevent air pockets, then cooled below the hydration point temperature after dispensing to increase viscosity and maintain structural integrity. This temperature-based parameter change resolves the contradiction between maintaining structural integrity and preventing air entrainment.
Solution Approach 2:
The patent applies preliminary action by preparing the cement mixture at elevated temperature before dispensing. The mixture is heated to above the hydration point temperature prior to mixing and dispensing operations, ensuring low viscosity and air-free flow. This preliminary thermal preparation prevents air pocket formation before the cement is applied to the honeycomb structure.
2Speed
If cement is cooled quickly to below hydration point temperature, then plug formation is rapid and structural integrity is achieved, but variability in plug depth increases due to premature setting
Solution Approach 1:
The patent uses parameter changes by controlling the cooling rate and temperature profile. The cement mixture is cooled from above the hydration point temperature to below it in a controlled manner, maintaining homogeneity during the transition. This controlled parameter change enables rapid plug formation while preventing premature setting that would cause depth variability.
3Manufacturing precision
If organic binder hydration is prevented during mixing, then viscosity remains low and air pockets are minimized, but the cement lacks structural integrity for handling
Solution Approach 1:
The patent applies parameter changes by using temperature control to manage the hydration state of the organic binder. During mixing and dispensing, the mixture is maintained above the hydration point temperature to prevent binder hydration and maintain low viscosity. After dispensing, the mixture is cooled below the hydration point temperature to trigger binder hydration and achieve structural integrity. This temporal separation of temperature states resolves the contradiction between uniform formation and structural integrity.
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 reduces air pockets and variability in plug depth, resulting in more uniform and effective blockages in particulate filters by maintaining low viscosity during mixing and dispensing, allowing for smooth, void-free cement formation.
Implementation Method 1
cooling the plugging mixture to a cooled temperature below a hydration point temperature of the organic binder in the plugging mixture
Data Source
AI summary
A method of plugging a honeycomb body includes mixing a plugging mixture at a mixing temperature, wherein the plugging mixture comprises a plurality of inorganic particles, inorganic binder, organic binder, and water; dispensing the plugging mixture into a patty mold at a dispensing temperature; cooling the plugging mixture within the patty mold to a cooled temperature, such that a cement patty is formed; and pressing the cement patty into a plurality of channels in a honeycomb body, wherein the mixing temperature and the dispensing temperature are above a hydration point temperature of the organic binder in the plugging mixture, and the cooled temperature is below the hydration point temperature of the organic binder in the plugging mixture.