Honeycomb Filter Defect Detection Using Permeable Screen
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Solution Overview
Problem
Existing methods for detecting defects in honeycomb filters, such as holes or cracks, are hindered by high background fog levels that obscure defect images, making it difficult to enhance the signal-to-noise ratio and accurately identify defective cells or plugs.
Innovation Solution
The use of a permeable member, such as a fine mesh screen with an anti-reflective surface, positioned adjacent to the outlet end face of the honeycomb filter, improves the signal-to-noise ratio by straightening the flow and decoupling background reflection, allowing for more effective defect detection through illumination and imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If fog is directed at the inlet end face to detect defects, then defect detection capability is provided, but background fog levels become high and obscure defect images
Solution Approach 1:
The patent extracts and removes the harmful background fog from the detection field by using a permeable member with specific pore size that allows defect-related fog to pass through while blocking background fog, thereby isolating the signal of interest from the noise
Solution Approach 2:
A permeable member (screen or mesh) is introduced as an intermediary component between the honeycomb filter outlet and the imaging system. This mediator selectively transmits fog particles while blocking background fog, improving the signal-to-noise ratio for defect detection
2Duration of action of moving object
If the filter is exposed to fog for a long period to become saturated, then filtration testing is completed, but background fog levels increase and obscure defect images
Solution Approach 1:
The permeable member serves as a mediator that allows the detection process to continue for extended periods without being compromised by accumulating background fog, as the screen selectively filters out background fog while transmitting defect signals
3Productivity
If higher pressures are used for operation, then productivity and detection speed improve, but flow distortion increases and complicates defect location
Solution Approach 1:
The permeable member acts as a flow-conditioning intermediary that straightens and uniformizes the fog flow exiting the honeycomb filter, reducing flow distortion even at higher operating pressures and enabling more accurate defect location
Solution Approach 2:
The patent changes the flow parameters by introducing the permeable member, which modifies the velocity profile and flow direction of the exiting fog, creating a more uniform flow pattern that facilitates accurate defect localization
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 enhances defect detection by increasing the signal-to-noise ratio, enabling the identification of subtle defects and allowing operation at higher pressures, thereby improving the accuracy and efficiency of identifying and locating defects in honeycomb filters.
Implementation Method 1
The permeable member improves the signal-to-noise ratio and also straightens the flow exiting from the end face
Implementation Method 2
a light source spaced from the member for illuminating particulates emerging through the permeable member
Implementation Method 3
a fine mesh screen with an anti-reflective surface, positioned adjacent to the outlet end face
Data Source
AI summary
A apparatus and method for detecting defects in a honeycomb body. In operation, the particulates emerge at an outlet end face of the honeycomb body through defects, if any, in the honeycomb walls and/or plugs and passes though a permeable member, such as a screen, where they are illuminated. The permeable member is disposed adjacent to and preferably in contact with the outlet end. Use of the permeable member improves the signal-to-noise ratio (SNR) such that defects may be more readily detected. The permeable member preferably includes an anti-reflective surface.