Filter Module End Cap Design for Liquid Separation
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Solution Overview
Problem
Existing filter modules for blood purification cannot completely prevent breakthroughs between liquid chambers due to shrinkage of the potting compound and mechanical or thermal loads, leading to potential contact between the two liquids.
Innovation Solution
A filter module design featuring a housing with a cylindrical central part and two housing end caps, where each end cap has a cylindrical stub and an annular protrusion forming a receiving area for the potting compound, which maintains liquid separation even if the potting compound partially detaches from the housing surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the potting compound is used to form a tight separation between liquid chambers, then the liquid space separation is improved, but the reliability deteriorates due to shrinkage and mechanical/thermal loads causing detachment
Solution Approach 1:
The housing is divided into a central housing part and two housing end caps that are attached to the ends of the central housing part. This segmentation allows the end caps to provide additional support and anchoring for the potting compound, distributing the mechanical and thermal stresses away from the critical sealing interface and preventing detachment that would compromise liquid space separation.
Solution Approach 2:
The housing end caps are pre-assembled onto the central housing part before the hollow fibers are potted. This preliminary action creates a prepared receiving area with proper geometry and support structures in place, ensuring that when the potting compound is later applied, it is immediately supported and anchored, preventing subsequent shrinkage-induced detachment and maintaining reliable liquid separation.
2Reliability
If the potting compound is shrunk or subjected to mechanical/thermal loads, then the material bond is lost, but the liquid space separation is maintained by the housing design
Solution Approach 1:
The housing end caps are designed with receiving areas and specific geometries that cushion and absorb the shrinkage forces and mechanical/thermal loads before they can affect the material bond between the potting compound and the housing. This beforehand cushioning protects the sealing interface, ensuring liquid space separation is maintained even when the material bond is compromised by environmental stresses.
3Ease of manufacture
If the housing is made as a single piece, then the manufacturing is simplified, but the ability to prevent breakthrough is reduced
Solution Approach 1:
The housing is segmented into a central housing part and two detachable housing end caps. While this increases the number of components, the end caps are designed to be attached to the ends of the central housing part, creating a modular assembly that is relatively simple to manufacture. More importantly, this segmentation provides additional geometric features and support structures that enhance the prevention of liquid breakthrough through the potting compound, outweighing the minor increase in manufacturing complexity.
Data Source
AI summary
A filter module includes a housing having a housing part and two end caps attached to the housing part. A bundle of semipermeable hollow fibers extend along the housing part and within the housing. A first liquid chamber extends within the fibers, and a second liquid chamber extends within the housing but outside the fibers. A potting compound forms a separating seal between the first and second liquid chambers. Each end cap has a stub that can be plugged onto the housing part, forming a receiving contour. The stub transitions into an end contour over a convex rounded section. The end contour has a through-opening lined by a rim that receives the fiber bundle and forms a protrusion. The protrusion forms a receiving area for the potting compound in the rounded section between the receiving contour and the protrusion.