Filter Cassette Inlet Reinforcement for Higher Flux Cleaning
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Solution Overview
Problem
Existing filtration cassettes face challenges with reduced flux rates and increased difficulty in cleaning when operating beyond design limits, particularly due to bending or folding of sheet materials at fluid inlet openings and increased pressure drops, leading to obstructed retentate channels and reduced efficiency.
Innovation Solution
The filtration cassette design incorporates capped permeate packs with stainless steel permeate sheets and permeate screen spacers to maintain channel integrity, prevent blockages, and enhance cleaning efficiency, while also using metal matrix permeate sheets for increased stiffness and resistance to fouling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If sheet materials are used at fluid inlet openings, then flexibility and ease of manufacture are improved, but bending or folding occurs under pressure leading to obstructed retentate channels and reduced flux rates
Solution Approach 1:
The inlet region is segmented from the rest of the filter structure by providing a separate reinforcement element (cap or collar) that attaches to the inlet opening. This segmentation allows the flexible sheet material to be used in the main body while the inlet region receives additional structural support to prevent bending and folding.
Solution Approach 2:
The inlet opening structure becomes a composite of the original sheet material combined with a reinforcement element made of stiffer material (such as metal or rigid plastic). This composite structure maintains the sealing and filtering properties of the original material while adding the structural integrity needed to prevent deformation under pressure.
2Ease of manufacture
If sheet materials are used at fluid inlet openings, then ease of manufacture is improved, but cleaning difficulty increases due to obstructed channels
Solution Approach 1:
By segmenting the inlet region with a separate reinforcement element, the design prevents the formation of obstructions that would hinder cleaning. The reinforcement maintains channel geometry open, allowing cleaning fluids to access and flush the filtration surfaces effectively.
Solution Approach 2:
The reinforcement element at the inlet performs a preliminary anti-action by preventing bending and folding before they can occur during operation. This proactive measure ensures that channels remain open and accessible for cleaning throughout the filter's service life.
3Productivity
If operating beyond design limits with higher pressures, then productivity is improved, but channel blockages occur due to bending and folding
Solution Approach 1:
The inlet opening structure becomes a composite of the original sheet material combined with a reinforcement element made of stiffer material (such as metal or rigid plastic). This composite structure maintains the sealing and filtering properties of the original material while adding the structural integrity needed to prevent deformation under pressure.
Solution Approach 2:
The reinforcement element provides beforehand cushioning by preemptively strengthening the inlet region against the high pressures that will be encountered during operation. This prevents the sheet material from bending or folding even when operating beyond standard design limits.
4Ease of manufacture
If standard permeate sheets are used, then ease of manufacture and cost are improved, but movement and fouling occur reducing flux rates
Solution Approach 1:
The permeate sheet material parameters are changed by transitioning from flexible, soft materials to stiffer, more rigid materials. This parameter change reduces sheet movement during operation and minimizes fouling, thereby maintaining higher flux rates throughout the filtration process.
Solution Approach 2:
The permeate sheet is replaced with or reinforced by composite materials that combine the filtering properties needed for the application with increased stiffness. This may involve using composite structures or materials that provide both porosity for filtration and rigidity to prevent movement and fouling.
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A filtration cassette including a multilaminate array of sheets including filter sheets alternating with permeate sheet members and retentate sheet members, and a cross-flow filter device comprising a multiplicity of stacked filtration cassettes of such type. The improvements associated with the filtration cassettes described herein include, but are not limited to, at least one of: reinforced inlet(s) providing for longevity and improved cleanability of the cassettes; spacer permeate screens to limit throughput restriction; stainless steel or otherwise stiffened permeate sheets to prevent movement and increase flux; and stainless steel permeate sheets that can be used with ultrasonic transmission to minimize fouling of the filter sheets and extend cleaning cycles. Advantageously, the filtration cassettes are more resistant to higher temperatures than the filtration cassettes of the prior art.