Terminal Filter Device with Flush Membrane Outlet
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Solution Overview
Problem
Existing filter devices for reducing microbial contamination in water systems face challenges with retrograde contamination, where bacteria can recolonize and air bubbles reduce the filter's effectiveness, leading to shorter service life and inefficient filtration.
Innovation Solution
A terminal filter device with cationically modified hydrophilic hollow-fiber membranes embedded in a casting compound, which are flush with the outlet end, preventing retrograde contamination by binding microbiological contaminants and ensuring efficient venting through hydrophobic membranes, and incorporating biocides in the housing and casting compound to maintain antimicrobial properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If conventional filter devices are used with non-flush outlet design, then the filter structure is simpler to manufacture, but retrograde contamination occurs and service life is reduced
Solution Approach 1:
The invention inverts the conventional filter outlet design by making the hollow fiber membrane ends flush with the outlet end of the housing, rather than protruding into the housing. This inversion eliminates the contaminated space where retrograde contamination typically occurs, thereby extending service life while maintaining manufacturing feasibility through standardized construction methods
Solution Approach 2:
The invention extracts and eliminates the contaminated space between the filter outlet and immediate water outlet by designing the hollow fiber membrane ends to be flush with the housing outlet end. This removal of the problematic space prevents bacterial recolonization and extends the filter's service life without significantly complicating the manufacturing process
2Reliability
If hydrophobic membranes are used for venting, then air bubbles are effectively removed, but microbial contaminants can still penetrate through
Solution Approach 1:
The invention employs a composite membrane structure combining hydrophobic and hydrophilic properties within the hollow fiber membranes. The hydrophobic portion provides venting functionality to remove air bubbles, while the hydrophilic portion with cationic modification binds and retains microbial contaminants, achieving both objectives simultaneously
Solution Approach 2:
The hollow fiber membranes exhibit local quality differentiation with distinct hydrophobic and hydrophilic regions or properties. The hydrophobic areas enable air bubble venting while the hydrophilic cationically modified areas provide microbial binding, allowing each local region to perform its specific function effectively
3Reliability
If cationic modification is applied to bind microbiological contaminants, then filtration efficiency increases, but the membrane may become fouled faster
Solution Approach 1:
The invention introduces biocides as intermediary substances embedded in the housing or casting compound. These biocides actively eliminate microbial contaminants that bind to the cationically modified membrane, preventing fouling and extending service life while maintaining high filtration efficiency through the cationic modification
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 solution significantly reduces the risk of retrograde contamination, extends the filter's service life to at least three months, and maintains efficient filtration behavior by preventing microbial growth and air bubble settlement, ensuring continuous effective water purification.
Implementation Method 1
the hydrophilic hollow-fiber membranes are functionalized by a cationic modification to bind microbiological contaminants
Implementation Method 2
porous hollow-fiber membranes, preferably with a pore size of 0.01-2 microns
Implementation Method 3
efficient venting through hydrophobic membranes
Data Source
Figure 1
AI summary
The invention relates to a terminal filter device for reducing microbiological contaminants, in particular bacteria and pyrogens, in an aqueous medium, especially water, comprising a housing with an inlet end for introducing the aqueous medium into the filter device and an outlet end for discharging the aqueous medium from the filter device, wherein hollow fiber membranes are arranged in the housing, each with an end facing the inlet end and an end facing the outlet end, wherein the ends of the hollow fiber membranes facing the inlet end are closed and the hollow fiber membranes are embedded with their outlet end in a potting compound in such a fluid-tight manner that they pass through the potting compound and are open at this end, wherein the hollow fiber membranes, preferably with a pore size of 0.01-2 µm and a preferably parallel arrangement to the longitudinal axis of the housing,The invention comprises at least a first group of hydrophilic hollow fiber membranes, wherein the hydrophilic hollow fiber membranes of the at least first group are functionalized for binding microbiological contaminants, in particular by a cationic modification, and wherein the housing, the potting compound, and the hollow fiber membranes are flush with each other at the outlet end of the filter device, thereby forming the direct outlet of the aqueous medium of the filter device. Furthermore, the invention relates to a use of this filter device and a corresponding method for reducing microbiological contaminants.