Floating Seal Vent Valve for Hemodialysis Filter Sterility
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Solution Overview
Problem
Current methods for venting filters in hemodialysis systems, such as those using hydrophobic filters, face issues with stability under pressure, high manufacturing costs, and the risk of sterility compromise when exposed to liquids, leading to potential contamination and manual intervention requirements.
Innovation Solution
A vent valve with a floating sealing element that moves between upper and lower positions, allowing for automatic venting while maintaining sterility and pressure resistance, reducing manual intervention and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hydrophobic filter is used for venting, then venting function is achieved, but pressure stability deteriorates and manufacturing cost increases
Solution Approach 1:
The vent valve is divided into separate functional components: a body with cavity, a movable sealing element, and a hydrophobic filter positioned at a specific location. This segmentation allows each component to perform its specific function optimally - the sealing element handles pressure sealing while the hydrophobic filter handles venting, resolving the contradiction between venting function and pressure stability
Solution Approach 2:
The movable sealing element acts as an intermediary between the hydrophobic filter and the liquid flow. It allows the hydrophobic filter to perform venting while preventing direct liquid contact that would compromise pressure stability, thus maintaining both venting function and pressure resistance
2Reliability
If a hydrophobic filter is used for venting, then venting function is achieved, but manufacturing cost increases
Solution Approach 1:
The hydrophobic filter is positioned only at the upper end of the cavity where venting is needed, rather than extending across the entire cross-section. This local application maintains the necessary venting function while significantly reducing the amount of expensive hydrophobic material required, thus lowering manufacturing costs
3Reliability
If the hydrophobic filter is exposed to liquid, then venting is achieved, but sterility is compromised leading to contamination risk
Solution Approach 1:
The movable sealing element serves as a protective intermediary that prevents direct liquid exposure to the hydrophobic filter during normal operation. It only allows controlled air passage when needed for venting, thereby maintaining sterility while achieving venting function
Solution Approach 2:
The sealing element is designed to prevent liquid from reaching the hydrophobic filter before liquid exposure can occur. This preliminary protective action ensures sterility is maintained by blocking the potential contamination pathway before it can be activated
4Ease of operation
If manual intervention is used for venting, then venting can be performed, but operational complexity increases
Solution Approach 1:
The vent valve is designed to perform venting automatically through the movement of the sealing element in response to pressure changes and liquid level variations. The system serves itself by using the natural physics of the situation (liquid displacement, pressure equalization) to trigger venting without requiring external manual operation, thereby simplifying operation while managing device complexity
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 enables efficient, automatic, and cost-effective venting of filters, preventing contamination and ensuring reliable operation during hemodialysis treatments by maintaining sterility and withstanding pressure fluctuations.
Implementation Method 1
The sealing element is freely movable between the first and second positions, such that a flow is formed between the first and second openings when the sealing element is in an intermediate position between the first and second positions
Implementation Method 2
From DE 4027531 C1, an arrangement is known which achieves venting by means of a hydrophobic filter at the upper end of a hollow fiber filter
Data Source
Figure 1a
Figure 1b
Figure 1c
AI summary
A vent valve for venting a filter is disclosed, comprising a cavity with an inlet and an outlet, and a sealing element inside the cavity for sealing the inlet in a first position and for sealing the outlet in a second position. The sealing element is freely movable between the first and second positions, and a flow is formed between the inlet and the outlet when the sealing element is in an intermediate position between the first and second positions.