Vacuum Filtration Head Shielding Against Membrane Retro-Contamination
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Solution Overview
Problem
Current vacuum filtration systems face issues with retro-contamination of membrane filters due to micro-droplets of residual sample fluid, leading to false positive results and increased costs, which existing solutions like enlarging the drain chamber or using a three-way valve are either ineffective or time-consuming and prone to errors.
Innovation Solution
A filtration head with a protective shield arranged in the drain chamber or channel to block direct paths of micro-droplets, reducing the void volume and maintaining a fluid path, and a method to modify existing filtration heads with a similar shield to prevent retro-contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drain chamber volume is increased to prevent retro-contamination, then the reliability of filtration is improved, but the size of the filtration head increases
Solution Approach 1:
The patent introduces a protective shield that creates a spatial barrier in the drain chamber, effectively adding a dimensional separation between the membrane filter and residual liquid. This shield divides the drain chamber into distinct zones, preventing micro-droplets from reaching the membrane without requiring a proportional increase in overall chamber volume.
Solution Approach 2:
The protective shield acts as an intermediary element between the membrane filter and the residual liquid in the drain chamber. It physically blocks the path of micro-droplets while allowing the liquid to drain through designated channels, thus preventing retro-contamination without needing to enlarge the entire filtration head.
2Reliability
If a three-way valve is used to flush the drain channel, then the reliability of filtration is improved, but the operation time and complexity increase
Solution Approach 1:
The protective shield provides passive, continuous protection against retro-contamination throughout the filtration process. It automatically blocks micro-droplet paths without requiring any manual intervention, flushing operations, or additional time-consuming steps, thus eliminating the time loss associated with valve operations.
Solution Approach 2:
The shield is pre-installed in the drain chamber to establish protection against retro-contamination before the filtration process begins. This preliminary structural arrangement eliminates the need for post-filtration flushing operations, saving time and simplifying the workflow.
3Reliability
If the drain channel length is increased to reduce micro-droplet generation, then the reliability of filtration is improved, but the device complexity and size increase
Solution Approach 1:
The patent extracts the droplet generation problem from the drain channel by introducing a protective shield in the drain chamber. This shield intercepts micro-droplets before they can form or travel through the drain channel, effectively removing the source of contamination without needing to modify or lengthen the channel structure.
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 shield effectively prevents membrane contamination by micro-droplets, reducing false positives and labor, while allowing for smaller filtration head design and efficient buffer liquid use, thus enhancing the reliability and efficiency of microbiological testing.
Implementation Method 1
a (protective) shield arranged in the filtration head so as to block/interfere with a fictive direct line connection between the opening of the drain channel into the drain chamber and the membrane filter
Implementation Method 2
perform the filtration by reducing the pressure downstream from an outlet drain channel of the filtration head by means of a vacuum pump in order to actively draw the liquid sample through the filtration membrane by the pressure differential on both sides of the membrane
Data Source
AI summary
A vacuum filtration head (1) having a receptacle for a support (2) for a membrane filter (3) for microbiological testing of a liquid substance to be drawn from an upstream side of the membrane filter (3) to a downstream side of the membrane filter (3) through the membrane filter (3), or the support (2) for such membrane filter (1), a drain chamber (4) located downstream of the support (2) and communicating with a downstream side of the membrane filter (3) receiving the liquid substance passed through the membrane filter (3), and a drain channel (5) communicating with the drain chamber (4) at an opening (9) and communicating with a vacuum. A protective shield (6) is arranged in the filtration head (1) interfering with a fictive direct line connection while retaining a fluid path (7) to the drain channel (5) past the protective shield (6).