Membrane Transfer Tool Dome Shaping for Bubble-Free Pad Contact
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Solution Overview
Problem
The existing membrane filtration method for microbiological testing faces challenges in applying a reagent to a deformed filter membrane after incubation, due to mismatched geometries and the inability to maintain pressure, leading to bubble formation and uneven application.
Innovation Solution
A method and tool that use a support frame with a shoulder and skirt to apply pressure and create a dome shape on the membrane, allowing it to be uniformly applied to a reagent pad while maintaining the original surface area, using a pressure difference and friction to prevent bubble formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the membrane is allowed to deform naturally after filtration and incubation, then the membrane surface area increases, but the membrane geometry becomes mismatched with the reagent pad causing bubble formation
Solution Approach 1:
The patent applies a pressure difference parameter change to transform the membrane from its deformed state back to its original planar configuration. By controlling the pressure differential across the membrane during transfer, the membrane surface area and geometry are restored to match the reagent pad dimensions, eliminating bubble formation while maintaining the increased surface area benefit for microorganism detection
Solution Approach 2:
The patent performs preliminary actions by pre-shaping the membrane into a dome configuration during filtration, then systematically reversing this deformation during the transfer process. The membrane is first formed into a dome to maximize surface area during filtration, then the pressure difference is applied to return it to planar form for pad contact, ensuring geometric matching before reagent application
2Area of moving object
If pressure is applied to give the membrane a dome shape, then the membrane surface area increases, but the sleeve cannot maintain pressure after removal leading to deformation
Solution Approach 1:
The patent introduces a support frame as an intermediary structure that maintains the membrane's dome shape and surface area expansion even after sleeve removal. The support frame provides mechanical stability and preserves the membrane configuration, allowing the membrane to retain its increased surface area without requiring continuous pressure application from the original sleeve
Solution Approach 2:
The support frame is prepared in advance with a configuration that matches the desired dome shape. By pre-configuring the support frame structure before membrane transfer, the membrane is guided into the correct three-dimensional configuration, ensuring shape stability is achieved proactively rather than requiring continuous active pressure maintenance
3Ease of operation
If the membrane is transferred without pressure difference control, then the transfer process is simpler, but bubbles form due to poor contact between membrane and pad
Solution Approach 1:
The patent employs pneumatic pressure difference control during the membrane transfer process. By applying controlled pressure differentials, the membrane is pressed uniformly against the reagent pad surface, ensuring complete contact and eliminating air bubbles. This pneumatic control method maintains operational simplicity while achieving precise, bubble-free contact that would be difficult to obtain through mechanical means alone
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
Ensures uniform application of the membrane to the reagent pad without bubble formation, returning the membrane to its original dimensions and maintaining contact for effective analysis.
Implementation Method 1
establishing a pressure difference between the cassette and the membrane support frame such that the membrane adopts the shape of a dome pointing towards the pad
Implementation Method 2
using a pressure difference and friction to prevent bubble formation
Data Source
AI summary
A method for transferring a filter membrane (130) bearing a retentate to a reagent pad (310), in which the membrane is mounted in a support frame (120) having a shoulder (121) and a skirt (122) projecting from the shoulder, the pad being mounted on a cassette (300) of complementary form to said skirt, the skirt being adapted to slide sealingly on the cassette until it comes into abutment formed by the shoulder, the method comprising the steps of sealingly engaging the skirt of the membrane support frame on the cassette, establishing a pressure difference between the cassette and the membrane support frame such that the membrane adopts the shape of a dome pointing towards the pad, while maintaining the pressure difference, applying a force on the frame so as to make the skirt slide on the cassette until contact is established between the end of the dome and the pad, maintaining a force on the frame so as to move it downward until it comes into abutment formed by the shoulder while maintaining the pressure difference.