Elastomeric Control Gasket Vacuum Channels for Pump Cassette Noise Reduction
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Solution Overview
Problem
Existing fluid handling systems with reusable components in medical and biotechnological applications face challenges in sterilization and maintenance, leading to increased costs and reduced equipment lifespan, while disposable membrane-based pumping cassettes offer a solution but require efficient actuation and sealing mechanisms to ensure reliable operation and safety.
Innovation Solution
A fluid pumping system comprising a pumping cassette with a flexible membrane and a base unit that provides positive or negative pressure through a pressure delivery block and control gasket, ensuring effective sealing and actuation of pump chambers and valves, with an elastomeric gasket that moves to occlude or open valve orifices and maintain a vacuum channel for precise pressure control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If disposable membrane-based pumping cassettes are used, then sterilization and maintenance costs are reduced and equipment lifespan is extended, but reliable actuation and sealing mechanisms are required to ensure operational reliability and safety
Solution Approach 1:
The control gasket serves as an intermediary component between the pressure delivery block and the cassette membrane. It transmits actuation pressure while maintaining sealing, and includes integrated vacuum channels that mediate the connection between vacuum ports and the space between the gasket and membrane, ensuring reliable operation without complex mechanisms
Solution Approach 2:
The control gasket performs multiple functions simultaneously: it provides sealing between the pressure delivery block and cassette membrane, transmits actuation pressure to control pump chambers and valves, maintains vacuum channels for negative pressure application, and protects passageways from fluid infiltration. This multi-functionality reduces the need for separate components
2Measurement precision
If a control gasket with vacuum channels is used, then precise pressure control is achieved, but the gasket structure becomes more complex
Solution Approach 1:
The vacuum channels are integrated directly into the control gasket structure, merging the vacuum delivery function with the sealing and pressure transmission functions. The channels extend from vacuum ports through the gasket to the space between the gasket and membrane, eliminating the need for separate vacuum delivery mechanisms
Solution Approach 2:
The control gasket is made of elastomeric material that provides flexibility while maintaining structural integrity. This flexible membrane structure allows the gasket to conform to the pressure delivery block and cassette membrane while incorporating vacuum channels, achieving precise pressure control without rigid complex structures
3Ease of operation
If the gasket elastomeric material moves to occlude valve orifices, then valve actuation is achieved, but noise and vibration increase
Solution Approach 1:
The elastomeric material properties of the control gasket are optimized to provide appropriate flexibility for valve actuation while damping vibrations. The material parameters (elasticity, density, damping characteristics) are selected to enable smooth movement that occludes valve orifices effectively while minimizing noise and vibration generation during operation
4Ease of operation
If vacuum ports penetrate the gasket, then negative pressure is applied for membrane movement, but fluid infiltration risk increases if membrane fails
Solution Approach 1:
The control gasket acts as an intermediary protective barrier between the vacuum ports and the cassette membrane. The elastomeric material provides a seal that prevents fluid infiltration through the vacuum port penetration points, while still allowing negative pressure to be transmitted to the membrane for effective actuation
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 system enables efficient and safe fluid handling with reduced maintenance costs, improved operational accuracy, and enhanced patient safety by ensuring reliable sealing and actuation of fluid pathways, minimizing noise and vibration, and preventing fluid infiltration.
Implementation Method 1
A control gasket is positioned over a pressure delivery block of the base unit, the control gasket having valve and pump control regions arranged to move toward or away from the pressure delivery block under force of positive or negative pressure
Implementation Method 2
a vacuum channel forming a perimeter around at least a portion of the peripheral portion of the actuation region, the vacuum channel defined by an inner wall contiguous with the peripheral portion of the actuation region
Data Source
Figure 1
Figure 1A
Figure 2
AI summary
A pump cassette comprising an outer flexible membrane covering flowpaths, valve chambers and pump chambers of the cassette is designed to be actuated by a control gasket on a base unit arranged to move designated valve and pump portions of the cassette membrane. The performance of a cassette valve may improved by optimizing the configuration of the valve control region of the control gasket overlying the cassette valve. This may improve both fluid flow through the valve and reduce the amount of vibratory noise associated with opening the valve. The gasket valve control or actuation region is at least partially bounded by a vacuum channel facing the outside of the gasket so that a constant vacuum can be applied between the gasket valve control or actuation region and the adjacent portion of the cassette membrane. An improved version of the vacuum channel comprises a flexible inner wall (contiguous with the valve control region) so that the inner wall flexes or partially collapses away from the cassette valve seat, while still maintaining patency of the vacuum channel during the application of negative pressure on the gasket valve actuation region to open the cassette valve.