Edge-Ported Pump Cassette Layout for Thin Pneumatic Manifolds
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Solution Overview
Problem
Existing fluid-handling cassettes with pneumatically actuated pumps and valves face challenges in minimizing thickness for compact arrangements and require efficient pressure distribution, particularly in hemodialysis systems, where direct plug-in connections and binary pressure control are advantageous but pose operational and assembly complexities.
Innovation Solution
A fluid handling cassette design with a planar shape featuring a midplate between outer plates, where actuation channels run parallel to the cassette face within inter-plate spaces, allowing for edge-mounted actuation ports and minimizing overall thickness, combined with a compact pressure distribution manifold for direct interface and binary pressure control using digital valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If actuation ports are located on the face or broad side of the cassette directly over the actuation chambers, then the route for actuation channels is shortest, but the overall cassette thickness increases due to spheroid or hemi-spheroid chamber walls extending above the plane
Solution Approach 1:
The patent relocates actuation ports from the broad face to the narrow edge of the cassette, changing the spatial dimension where ports are positioned. This allows actuation channels to route through the thickness of the cassette rather than extending horizontally, reducing the horizontal route length while minimizing the vertical extension of chamber walls above the cassette plane.
2Adaptability or versatility
If pump modules comprise blocks sandwiched or laminated together with embedded pneumatic actuation channels, then pumping functionality is integrated, but the overall device thickness becomes greater than desirable
Solution Approach 1:
The patent divides the cassette into distinct functional layers: a midplate containing pump and valve stations, outer plates providing structural boundaries, and inter-plate spaces housing actuation channels. This segmentation allows each component to be optimized independently, with actuation channels confined to inter-plate spaces rather than embedding them within thick structural blocks.
3Adaptability or versatility
If pump cassettes are connected to pneumatic manifold via flexible tubes, then connection flexibility is provided, but assembly challenges and operational complexity increase significantly
Solution Approach 1:
The patent integrates the pneumatic manifold directly into the cassette structure by positioning actuation ports on the narrow edge that can be plugged directly into the manifold. This merging of the manifold connection with the cassette body eliminates the need for separate flexible tubing connections, reducing assembly steps and operational complexity while maintaining pneumatic connectivity.
4Productivity
If multiple fluid handling cassettes are mounted next to each other in tight spaces, then system capacity is increased, but space constraints make direct plug-in connections to manifold difficult
Solution Approach 1:
The patent employs an asymmetric configuration where all actuation ports are positioned on the narrow edge of the cassette rather than distributing them across the broad face. This asymmetric port arrangement allows multiple cassettes to be mounted in tight spaces with their narrow edges aligned, enabling simultaneous direct plug-in connections to the manifold without requiring complex routing for each individual cassette.
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
This design enables compact, efficient fluid handling with reduced thickness, facilitating easier assembly and operation by allowing direct plug-in connections and precise pressure control, enhancing reliability and cost-effectiveness in applications like hemodialysis.
Implementation Method 1
a cassette is designed to be fluidically connected to a pneumatic actuation manifold having electromechanical valves that selectively distribute positively or negatively pressurized gas or air to the cassette
Implementation Method 2
Liquid-handling cassettes comprising diaphragm pumps and/or valves can be actuated fluidically (either hydraulically or pneumatically)
Data Source
AI summary
A fluid-handling cassette comprising a plurality of diaphragm valves and pumps is configured to have its actuation ports located along a thin or narrow edge of the cassette. Actuation channels within the cassette lead from the actuation ports to actuation chambers of the valves and pumps in a space between plates that comprise the cassette. The individual plates have a nominal thickness that is sufficient to provide a rigid ceiling for the actuation channels, but sufficiently thin to minimize the overall thickness of the cassette. The cassette can be plugged into or unplugged from an actuation receptacle or a manifold by its narrow edge. A plurality of such cassettes can be stacked together or spaced apart from each other to form a cassette assembly, providing for a convenient way to install and remove the cassette assembly from its actuation receptacle. The arrangement allows for an improved way of connecting a complex cassette assembly to its associated pressure distribution manifold without the use of a plurality of flexible connecting tubes between the two.