Crossflow Filter Hairpin Bends and Guide Walls
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Solution Overview
Problem
Current crossflow filter devices suffer from inefficiencies due to incomplete seals and laminar flow, leading to short-circuiting and reduced filtration efficiency, particularly in devices like the Vivaflow 50R and Vivaflow 200, which impairs the concentration and separation of biomolecules and other macromolecules.
Innovation Solution
The crossflow filter device incorporates a flow channel with hairpin bends and guide walls that force the retentate liquid to turn through at least 270°, creating turbulence and breaking up laminar flow, while a resiliently deformable gasket ensures a fluid-tight seal, eliminating short-circuiting and enhancing filtration efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the flow channel is formed as a recess in the retentate-side plate with raised parts pressing against the membrane, then the flow path is confined, but incomplete sealing occurs allowing short-circuiting
Solution Approach 1:
A gasket is introduced as an intermediary sealing element between the retentate-side plate and the membrane. The gasket comprises a base layer and a flow channel-defining layer that together create a fluid-tight seal, preventing short-circuiting while maintaining the confined flow path structure.
Solution Approach 2:
The gasket utilizes flexible material properties to conform to the membrane surface and create an effective seal. The flow channel-defining layer can be made from flexible materials that adapt to slight variations in membrane positioning, ensuring reliable sealing.
2Device complexity
If straight flow channels are used, then the device structure is simple, but laminar flow occurs reducing filtration efficiency
Solution Approach 1:
The flow channel is designed with hairpin bends instead of straight sections. These curved paths force the retentate liquid to change direction repeatedly, creating turbulence that enhances filtration efficiency by preventing laminar flow patterns.
Solution Approach 2:
The flow channel incorporates periodic hairpin bends along its length, creating repeated cycles of flow direction changes. This periodic turbulence generation maintains enhanced filtration performance throughout the entire flow path.
3Productivity
If hairpin bends with 270° turns are implemented, then turbulence is increased improving filtration, but device complexity increases
Solution Approach 1:
The gasket integrates two functions into a single component: sealing the flow channel against the membrane and defining the hairpin bend geometry. This merging reduces the number of separate parts needed while achieving both turbulence generation and reliable sealing.
Solution Approach 2:
The flow channel-defining layer of the gasket serves multiple purposes: creating the fluid-tight seal, establishing the hairpin bend path, and controlling flow distribution across the membrane surface. This multi-functionality reduces overall device complexity despite the complex flow path.
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 design significantly increases turbulence in the retentate liquid, improving filtration efficiency by inducing chaotic changes in pressure and flow velocity, leading to enhanced separation and concentration of biomolecules and other macromolecules, and allowing for the use of different membrane types within the same device.
Implementation Method 1
The respective guide wall defining the line of the inner radius of each hairpin bend is shaped such that retentate liquid flowing along that guide wall has to turn through at least 270° to complete the hairpin bend. This significantly increases turbulence in the retentate liquid.
Implementation Method 2
breaking up laminar flow
Implementation Method 3
Crossflow filtration is a process in which a pressurised feed liquid is forced to flow tangentially over a membrane permeable to a filtrate derivable from the feed liquid.
Implementation Method 4
a membrane permeable to a filtrate derivable from the feed liquid
Implementation Method 5
a resiliently deformable gasket ensures a fluid-tight seal
Data Source
AI summary
A crossflow filter device for filtering a pressurised feed liquid is provided. The crossflow filter device comprises: a filter membrane; a flow channel for the pressurised feed liquid which extends in a path over a retentate surface of the membrane such that the direction of flow in the channel is tangential to the retentate surface, and a filtrate derived from the feed liquid passes through the membrane leaving retentate liquid in the flow channel; and a collection chamber for the filtrate formed on an opposite, filtrate surface of the membrane. The crossflow filter device further comprises a sealed housing having a retentate side and a filtrate side which enclose therebetween the flow channel, the filter membrane and the collection chamber. The path for the flow channel winds back and forth over the retentate surface of the membrane producing plural hairpin bends, and the crossflow filter device further comprises flow channel guide walls provided at an inner surface of the retentate side of the housing to define the path of the flow channel over the retentate surface of the membrane. The respective guide wall defining the line of the inner radius of each hairpin bend is shaped such that retentate liquid flowing along that guide wall has to turn through at least 270° to complete the hairpin bend.