Insertable Molded Valves for Hot-Plate-Welded Centrifuge Cassettes
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Solution Overview
Problem
The incorporation of wax elements into valves during the manufacture of centrifuge cassettes limits manufacturing methods, as hot plate welding, a preferred method for cost and efficiency, is not feasible due to deformation of wax elements under heat and pressure, necessitating the development of valves compatible with hot plate welding and capable of operating in sterile fluidic channels under high G-fields.
Innovation Solution
The design and manufacturing of Normally Open Valves (NOVs) and Normally Closed Valves (NCVs) with interference seal members, valve seal posts, and ribs, which are injection molded and inserted into the cassette after the plates have been joined via hot plate welding, allowing for precise alignment and secure seating within the fluidic channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wax elements are incorporated into valves during cassette manufacture, then valve functionality is achieved, but manufacturing method selection is limited and hot plate welding cannot be used
Solution Approach 1:
The valve is divided into separate components: a valve body and a seal element. The seal element is inserted into the valve body after the cassette plates are welded together, rather than being integrated during the molding process. This segmentation allows the cassette to be manufactured using hot plate welding without compromising the seal element.
Solution Approach 2:
The cassette plates are welded together first using hot plate welding to create a sterile, sealed structure. After welding, the valve components are inserted into the pre-formed cassette structure. This preliminary action of welding before valve insertion enables the use of hot plate welding while maintaining valve functionality.
2Productivity
If hot plate welding is used for cassette assembly, then manufacturing cost and efficiency are improved, but valves with wax elements deform under heat and pressure
Solution Approach 1:
The valve system is segmented into a valve body and a separate seal element. The seal element is inserted after the hot plate welding process, avoiding exposure to welding heat and pressure. This allows efficient hot plate welding while preserving the dimensional stability and functionality of the valve components.
3Adaptability or versatility
If valves are inserted after cassette assembly, then compatibility with hot plate welding is achieved, but alignment precision within fluidic channels becomes more difficult
Solution Approach 1:
Valve insertion slots and positioning features are pre-formed in the cassette plates during the injection molding process, before welding. These pre-formed features guide the valve components into correct alignment after welding, ensuring precise positioning within the fluidic channels despite the post-assembly insertion approach.
Solution Approach 2:
Interference seal members act as intermediaries between the valve body and the fluidic channel walls. These seal members facilitate precise alignment and secure seating of the valve within the channel, compensating for any minor misalignments that may occur during post-assembly insertion.
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
Enables the use of hot plate welding for cassette assembly while maintaining valve integrity under high fluidic pressures and ensuring sterile fluid control, enhancing the compatibility and reliability of the centrifuge cassette for fluid separation processes.
Implementation Method 1
a heating element for actuating the at least one molded valve
Implementation Method 2
a centrifugal cassette or cartridge may be used to separate human or animal blood
Implementation Method 3
The at least one interference seal member is configured to cooperate with at least one interference seal member of a valve seat of a fluidic channel
Data Source
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AI summary
Provided is a centrifuge cassette assembly (800) for separating a fluid and related method of manufacture. The cassette assembly includes a first chamber, a second chamber (308), a fluidic channel (808) creating a fluid connection between the first chamber and the second chamber, at least one molded insertion valve (600, 700) configured to control the flow of fluid in the fluidic channel and a heating element (802) for actuating the at least one molded valve. Further provided are Normally Open Valves (NOVs) (700) and Normally Closed Valves (NCVs) (600) which are capable of insertion into, and which control the fluid flow of, the centrifuge cassette assembly.