Semi-rigid Blood Filter Unit Centrifugation Impact Resistance
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Solution Overview
Problem
Existing filter units for blood and blood derivatives, particularly those made of rigid materials, are prone to cracking or bursting during centrifugation, leading to contamination and loss of blood content, and flexible units may swell or collapse, compromising filtering efficiency and handling safety.
Innovation Solution
A filter unit with a semi-rigid thermoplastic polymer body made from injection-molded half-shells with a modular filter element and ribbed structure, providing stability and flexibility to prevent damage during centrifugation while maintaining high filtering efficiency, and a continuous weld line for durable assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid material filter units are used, then structural strength and stability are improved, but they become prone to cracking or breaking during centrifugation due to impacts generated within the rotor
Solution Approach 1:
The filter unit employs a shell made of flexible polymer material (such as polyethylene or polypropylene) instead of rigid material. This flexible shell can deform and absorb impacts generated during centrifugation, preventing cracking and breaking while maintaining structural integrity. The flexibility allows the shell to adapt to centrifugal forces without fracturing, directly resolving the contradiction between strength and reliability during centrifugation.
2Reliability
If flexible polymer material is used for the filter body, then resistance to impact during centrifugation is improved, but the filter unit may collapse or swell compromising filtering efficiency
Solution Approach 1:
The filter unit is segmented into distinct functional components: a flexible outer shell for impact resistance, an intermediate layer (in some embodiments) for structural support, and an internal filter element for filtration. This segmentation allows each component to perform its specific function optimally - the shell absorbs impacts while the internal structure maintains filtering efficiency without collapsing or swelling.
Solution Approach 2:
The filter unit utilizes composite construction with multiple layers or materials - combining flexible polymer material for the shell with potentially different materials for the intermediate layer and filter element. This composite structure integrates the impact resistance of flexible materials with the structural stability needed to maintain filtering efficiency during centrifugation.
3Ease of manufacture
If the filter element is held by welding the shells at the perimetral edges, then assembly simplicity is improved, but the filter element can deform close to the edges within the cavity compromising optimum filtering action
Solution Approach 1:
An intermediate layer is introduced as a mediator between the flexible shell and the filter element. This intermediate layer provides a stable mounting surface for the filter element, preventing deformation near the edges while maintaining the simple welded assembly structure. The intermediate layer acts as a buffer that decouples the welding process from the filter element positioning, resolving the contradiction between assembly simplicity and positioning accuracy.
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 semi-rigid filter unit effectively prevents damage to itself and other components during centrifugation, ensures high filtering efficiency, and is easy to handle, with a comparable packing factor to rigid units, demonstrating improved performance and safety.
Implementation Method 1
Filters made of rigid material (PVC, acrylics, or others) which are centrifuged, sometimes at high speed, may become cracked or broken due to impacts generated within the rotor of the centrifuge
Implementation Method 2
During the separation of blood derivatives each unit is then centrifuged, forming a part together with a bag of whole blood and various bags for collecting the blood derivatives
Data Source
AI summary
A filter unit for blood and blood derivatives comprises a body (1) defined by two injection-moulded half-shells (2, 3) of thermoplastic polymer material, there being present between said half-shells (2, 3) a cavity (4) containing a filtering element (5) having two opposing flat faces (5A, 5B), an inlet opening (9) and an outlet opening (13) made on the opposing outer surfaces (2K, 3K) of said body (1) communicating with said cavity (4). Each of said half- shells (2, 3) comprises a projecting perimetral flange (30), the flanges (30) of the overlapping half-shells being welded together to form a flange (40) of the body of the filter unit and connect the two half-shells (2, 3) together, the filtering element (5) being wholly contained within the cavity (4) of such body (1) and pressed by shelves (55) projecting into such cavity (4) from each half-shell (2, 3) in the vicinity of its perimetral border (70) and on the two opposing faces (5A, 5B), said shelves (55) retaining said filtering element (5) in a stable position within cavity (4), said thermoplastic polymer material being yielding and semi-rigid.