Radial Flow Ostomy Filter Assembly with Dual Membranes
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Solution Overview
Problem
Existing deodorizing gas filters for ostomy pouches face issues with clogging due to liquid and solid waste, reduced flow rates due to extended flow paths, and increased costs from protective membranes, as well as inefficiencies in liquid repellency and deodorization under pressure.
Innovation Solution
A high-performance deodorizing gas filter assembly with dual microporous hydrophobic and oleophobic membranes, featuring a radial flow filter design with a gas impermeable cover and an external outlet membrane, achieving high air transmission rates and liquid repellency while maintaining deodorization efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an extended flow path is used in a radial flow filter to improve deodorization efficiency, then deodorizing performance is improved, but flow resistance increases and flow rate decreases
Solution Approach 1:
The filter transitions from axial flow (one-dimensional through-thickness flow) to radial flow (two-dimensional in-plane flow), allowing the gas to travel along the extended surface area of the filter rather than directly through its thickness. This dimensional change enables a longer deodorization path without proportionally increasing flow resistance, as the flow distributes across the filter surface area.
Solution Approach 2:
The filter utilizes a porous structure with optimized pore size distribution and porosity to balance deodorization efficiency and flow resistance. The porous material allows gas to permeate through the filter matrix while providing sufficient surface area for odor absorption, achieving both extended flow path and acceptable flow rate.
2Reliability
If a protective microporous membrane is added to prevent filter clogging, then filter reliability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The protective microporous membrane is integrated directly onto the filter surface through lamination or coating, merging the protection function with the filter structure itself. This eliminates the need for separate protective layers or complex assembly steps, reducing device complexity while maintaining reliability.
Solution Approach 2:
A microporous membrane with appropriate pore size is used to provide liquid and solid particle protection while maintaining gas permeability. The porous structure allows flatus gases to pass through while blocking larger contaminants, achieving protection without significantly impeding flow or requiring complex assembly.
3Reliability
If a microporous hydrophobic membrane is used to protect the filter inlet, then liquid repellency is improved, but flow resistance increases
Solution Approach 1:
The membrane parameters are optimized by adjusting pore size, porosity, and hydrophobic coating characteristics to achieve the minimum required breakthrough pressure while minimizing flow resistance. By carefully controlling these parameters, the membrane provides adequate liquid protection without excessively impeding gas flow.
Solution Approach 2:
The membrane combines a porous substrate with a hydrophobic coating layer to create a composite structure that provides both liquid repellency and acceptable gas permeability. The hydrophobic layer prevents liquid penetration while the porous substrate maintains gas flow pathways, achieving both protection and flow performance.
4Reliability
If the filter is mounted inside the pouch to protect it from external liquid, then protection is improved, but the filter becomes vulnerable to water entering through the vent opening during showering
Solution Approach 1:
A microporous hydrophobic membrane is placed over the vent opening to block water ingress while allowing gas egress. The porous structure with hydrophobic properties enables the membrane to repel liquid water droplets while maintaining permeability to flatus gases, preventing water from entering the filter through the vent during showering.
Solution Approach 2:
The microporous hydrophobic membrane acts as an intermediary barrier between the external environment and the filter, selectively blocking harmful liquid water while permitting beneficial gas flow. This intermediary layer protects the filter from water ingress through the vent opening without interfering with its deodorization function.
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 filter assembly achieves air transmission rates greater than 4.5 cc/sec, high liquid repellency, and extended deodorization periods, with breakthrough pressures exceeding 32.4 kPa and crack pressures below 6.89 kPa, while maintaining low production costs and ease of assembly.
Implementation Method 1
dual microporous hydrophobic and oleophobic membranes
Implementation Method 2
dual microporous hydrophobic and oleophobic membranes
Implementation Method 3
fibrous elements coated with finely-divided activated carbon particles
Implementation Method 4
activated carbon therein
Implementation Method 5
gases flow along the plane of a relatively flat filter rather than directly or axially through the thickness
Implementation Method 6
breakthrough pressure when subjected to a pressure increase
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
An ostomy pouch (10) and high-performance gas filter assembly (20) therefor, in which the filter assembly includes an envelope (21) defining a filter chamber (24) containing a radial flow deodorizing filter pad (26). The pad's opposite faces (26a, 26b) are joined to the inner surfaces of the envelope in such way that the periphery of the pad is fully exposed within the chamber. A first passage (29) extends through the filter and communicates with a first opening (34) in a wall of the envelope over which a first microporous membrane (35) extends. A second opening (37) extends through the opposite wall of the envelope at a distance spaced laterally from the first opening, and a second hydrophobic microporous membrane (38) extends over the second opening. In a preferred embodiment, the filter pad is oblong in shape and has a second passage (140) spaced laterally from the first passage (129) and communicating with the second aperture.