Particulate Filter Powder Loading With Axial Deposition Control
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Solution Overview
Problem
Existing methods for loading dry powder into porous structures of filters are inefficient in controlling the distribution and location of the powder, affecting backpressure, soot location, and filtration efficiency.
Innovation Solution
A method and apparatus that utilize a secondary gas flow to control the axial distribution of dry powder on a porous substrate by adjusting the pressure and flow rate of the secondary gas flow, creating a turbulent zone at the inlet face to skew the powder distribution, and using a ring air blade to generate a 360° gas flow for deposition control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a primary gas flow is used to entrain and transfer dry powder through the porous substrate, then the powder can be loaded into the porous structure, but the axial distribution of the powder cannot be controlled
Solution Approach 1:
The gas flow system is segmented into two independent flows: a primary gas flow for entraining and transporting powder through the substrate, and a secondary gas flow for controlling axial distribution. This segmentation allows each flow to perform its specific function independently, enabling precise control over powder deposition patterns without increasing overall system complexity.
Solution Approach 2:
The invention controls powder axial distribution by changing parameters of the secondary gas flow, specifically its pressure and flow rate. By adjusting these parameters, the turbulent zone characteristics are modified, which in turn controls where the powder deposits within the porous structure. This parameter-based control provides a simple yet effective method to achieve precise deposition patterns.
2Reliability
If the dry powder loading is increased to improve filtration efficiency, then the filtration performance improves, but the backpressure increases
Solution Approach 1:
The invention enables local quality control by allowing different axial distributions of dry powder within the porous substrate. By controlling where the powder deposits (inlet end vs outlet end), the filtration characteristics can be optimized for specific applications. This local control allows achieving high filtration efficiency in critical regions while managing backpressure through strategic powder placement, rather than uniform loading throughout the substrate.
3Productivity
If the spray device is positioned closer to the inlet face to improve powder deposition, then the deposition efficiency improves, but the apparatus must be modified for different substrate sizes
Solution Approach 1:
The secondary gas flow system serves multiple functions: it controls axial powder distribution, creates turbulent zones for enhanced deposition, and enables the apparatus to handle various substrate sizes without modification. By positioning the spray device at a fixed distance and using the secondary gas flow to create the necessary turbulence and control deposition patterns, the system achieves universal applicability across different substrate dimensions while maintaining high deposition 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 method allows for controlled and repeatable deposition of dry powder, improving backpressure, soot location, and filtration efficiency, while also enabling easy cleaning and accommodating various substrate sizes without apparatus modification.
Implementation Method 1
establishing a primary gas flow through the porous substrate from the inlet face to the outlet face by using the vacuum generator to apply a pressure reduction to the outlet face of the porous substrate
Implementation Method 2
spraying the dry powder into or within the inlet chamber such that dry powder is entrained in the primary gas flow and passes through the inlet face of the porous substrate
Implementation Method 3
The secondary gas flow is believed to create a localised turbulent zone at or above the inlet face that reduces said momentum and/or imparts a transverse component to the momentum that has the effect of skewing the axial distribution of the dry powder that is deposited towards the inlet end of the porous substrate
Data Source
AI summary
A method and apparatus for applying a dry powder to a porous substrate (10) comprising:a) locating the porous substrate (10) in a holder (2) such that an inlet face (11) is in communication with an inlet chamber (15) and an outlet face (12) is in communication with a vacuum generator;b) establishing a primary gas flow through the porous substrate (10) using the vacuum generator to apply a pressure reduction to the outlet face (12);c) spraying the dry powder into or within the inlet chamber (15) such that dry powder is entrained in the primary gas flow and passes through the inlet face (11) of the porous substrate (10) to contact a porous structure (13) of the porous substrate (10);d) during the spraying of the dry powder directing a secondary gas flow onto and/or across the inlet face of the porous substrate (10); ande) using a pressure and/or a flow rate of the secondary gas flow to control an axial distribution of the dry powder that is deposited in the porous structure (13) of the porous substrate (10).